Publication database - Forschungszentrum Dresden-Rossendorf

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< Seite 1 von 2 >   Gesamtzahl lt. Auswahl: 125 Title records (100 Title records je Seite)
173 Publications
 
Modified 3½-Cell SC Cavity Made of Large Grain Niobium for the FZD SRF Photoinjector
Murcek, P.; Buettig, H.; Michel, P.; Moeller, K.; Arnold, A.; Teichert, J.; Xiang, R.; Freitag, M.; Kneisel, P.
Abstract: An SRF photoinjector has been successfully tested in FZD under the collaboration of BESSY, DESY, FZD, and MBI. In order to improve the gun cavity quality and thus reach a higher gradient, a new 3+1/2 superconducting cavity is being fabricated in cooperation with JLab. The modified cavity is made of large grain niobium, composed of one filter choke, one special designed half-cell (gun-cell) and three TESLA cavities. In this paper, the main updates of the new cavity design will be explained in detail. The deformation of the filter choke and the gun-cell, which is caused by pressure fluctuation in the He-line and also by the effect of the Lorentz force, will be minimized by stiffening between the filter choke and the gun-cell. Meanwhile, the cathode hole in the choke and gun-cell is enlarged for better rinsing. To simplify assembly, the NbTi pick-up will be welded directly on the wall of filter choke.

  • Poster:
    SRF 2009 Conference, 20.-25.09.2009, Berlin and Dresden, Germany
  • Contribution to Proceeding:
    SRF 2009 Conference, 20.-25.09.2009, Berlin and Dresden, Germany
Registration 11.12.2009 08:44, No. 13496
 
ERL 2009 WG1 Summary Paper: Drive Lasers and RF Gun Operation and Challenges
Lewellen, J. W.; Bluem, H.; Burrill, A.; Grimm, T. L.; Kamps, T.; Legg, R.; Liu, K.; Rao, T.; Smedley, J.; Teichert, J.; Zhang, S.
Abstract: Working Group I of the 2009 Energy Recovery Linac Workshop focused on high-brightness, high-power electron beam sources for energy recovery linacs (ERLs), and relevant technology such as development of drive lasers. The WG1 summary paper was broken into two parts: DC guns and loadlocks; and RF guns and drive lasers. This was done both to retain more manageable paper sizes, and because SRF guns are in an earlier stage of development than DC guns. This paper describes the advances, concepts, and thoughts for the latter topics presented at the workshop.
There are many challenges to the successful operation of SRF guns as high-brightness, high-average-current beam sources. These combine the set of challenges for high-current SRF cavities (fabrication, cleaning and processing, HOM extraction, etc.), with challenges for high-average-current photocathode sources (photocathode fabrication, quantum efficiency and lifetime, drive laser technology, etc.). New challenges also arise from this combination, such as the requirement for having removable cathodes in an SRF cavity. Practical approaches have been, and are currently being, found to address the problems, and the base of knowledge and experience continues to grow.
Alternate ideas are also beginning to make inroads. Hybrid DC-SRF guns, pioneered by Peking University, offer promise for combining the best features of both technologies. Quarter-wave SRF cavities offer compact size for a given frequency, potentially easier fabrication than elliptical cells, and very high transit-time factors for quasi-DC operation. Also, the use of normal-conducting cavities, usually dismissed out of hand due to the required RF power consumption, may become practical with advanced cavity designs.
This paper summarizes the state-of-the-art of drive lasers, cathode development and RF gun-based injectors for ERL beam sources The focus in the field has been on DC and SRF guns to date, but interesting approaches for hybrid DC/SRF guns and normal-conducting RF guns are also presented. The paper concludes with discussions of operational issues and concerns, technical issues related to beam source realization, and future concepts.

  • Contribution to Proceeding:
    Energy Recovery Linac Workshop ERL´09, 08.-12.06.2009, Ithaca, USA
Registration 11.12.2009 08:25, No. 13495
 
FZD SRF Gun Development and Testing
Teichert, J.; Arnold, A.; Büttig, H.; Janssen, D.; Justus, M.; Lehnert, U.; Michel, P.; Moeller, K.; Murcek, P.; Schneider, C.; Schurig, R.; Staats, G.; Staufenbiel, F.; Tietze, H.; Xiang, R.; von der Horst, B.; Matheisen, A.; Stephan, J.; Kamps, T.; Rudolph, J.; Schenk, M.; Klemz, G.; Will, I.; Volkov, V.
Abstract: kein Abstract verfügbar.

  • Invited lecture (Conferences):
    Energy Recovery Linac Workshop ERL´09, 08.-12.06.2009, Ithaca, USA
Registration 11.12.2009 08:04, No. 13494
 
Three years of cw-operation at FELBE - Experiences and applications
Seidel, W.; Cizmar, E.; Drachenko, O.; Helm, M.; Justus, M.; Lehnert, U.; Michel, P.; Ozerov, M.; Schneider, H.; Schurig, R.; Stehr, D.; Wagner, M.; Winnerl, S.; Wohlfarth, D.; Zvyagin, S.; Kehr, S. C.; Eng, L. M.
Abstract: This paper reviews the basic properties of the infrared free-electron laser FELBE at the Forschungszentrum Dresden-Rossendorf. A few highlight experiments using the cw-operation are discussed. Driven by a superconducting linear accelerator, FELBE continuously generates infrared pulses with a repetition rate of 13 MHz. In addition, operation in a macropulse modus (pulse duration >100µs, repetition rate ≤ 25 Hz) is possible. At present FELBE delivers µJ pulses with typical duration of about 0.9-30 ps in the wavelength range 4-230 µm. Furthermore we give an outlook on the experiments will use the beam of FELBE in the High Magnetic Field Laboratory Dresden (HLD). The HLD will provide pulsed magnetic fields up to 60 T. It operates as a user facility since 2007.

  • Poster:
    30th International Free Electron Laser Conference FEL 2008, 24.-29.08.2008, Gyeongju, Korea
  • Contribution to Proceeding:
    30th International Free Electron Laser Conference FEL 2008, 24.-29.08.2008, Gyeongju, Korea
Registration 18.11.2008 17:09, No. 11937
 
Radiation Source ELBE – Electromagnetic Radiation for Fundamental Research
Justus, M.
Abstract: Since 2003, the Radiation Source ELBE at the Research Centre Dresden-Rossendorf (FZD) delivers infrared light, X-rays and Bremsstrahlung of high intensity for fundamental research. The experimental proposals are associated with the FZD programs “Advanced Materials Research”, “Cancer Research” as well as “Nuclear Safety Research and come from the institute itself, as well as from international guests.
The design and the technical implementation of the 40 MeV superconducting electron beam linear accelerator are explained with regard to the generation of the different types of secondary radiation. The article also highlights beam diagnostics and optimization of the beam quality and availability with respect to the different demands on its main properties (energy, bunch charge, emittance, time structure) and the ongoing installation of facility parts.
Keywords: ELBE

  • Lecture (Conference):
    DPG Frühjahrstagung Freiburg 08, 03.-07.03.2008, Freiburg, Deutschland
Downloads:
Slides PDF

Registration 09.05.2008 13:51, No. 11314
 
The IR-Beam Transport System from the ELBE-FELs to the User Labs
Seidel, W.; Grosse, E.; Justus, M.; Leege, K.-W.; Proehl, D.; Schlenk, R.; Winter, A.; Wohlfarth, D.; Wuensch, R.
Abstract: In the Forschungszentrum Dresden-Rossendorf, two free-electron lasers (FELs) have been put into operation. They produce laser light in the medium and the far infrared wavelength range (4-150 ìm). The IR ligh is transported to several laboratories in the same building and to the adjacent building of the High Magnetic Field Laboratory as well, where the experimental setups are up to 70maway from the FELs. Constructional peculiarities, the large wavelength range, the high average power in cw regime, and the beam property requirements of the users pose a challenge to the beam line design. The transport system includes vacuum pipes, diagnostic elements, plane and toroidal gold-covered copper mirrors, and exit windows. The designed transport system produces a beam waist at selected spots in each laboratory representing a magnified image of the outcoupling hole. Spot size and position are independent of the wavelength.

  • Poster:
    29th International Free Electron Laser Conference FEL 2007, 26.-31.08.2007, Novosibirsk, Russia
  • Contribution to Proceeding:
    29th International Free Electron Laser Conference FEL 2007, 26.-31.08.2007, Novosibirsk, Russia
    Proceedings of FEL 2007
Registration 25.10.2007 17:14, No. 10657
 
Comparison of isoscalar vector meson production cross sections in proton-proton collisions
Abdel-Bary, A.; Abdel-Samad, S.; Brinkmann, K.-Th.; Clement, H.; Dietrich, J.; Doroshkevich, E.; Dshemuchadse, S.; Ehrhardt, K.; Erhardt, A.; Eyrich, W.; Filippi, A.; Freiesleben, H.; Fritsch, A.; Gillitzer, A.; Hesselbarth, D.; Jaekel, R.; Karsch, L.; Kilian, K.; Kuhlmann, E.; Marcello, S.; Michel, P.; Moeller, K.; Morsch, H. P.; Pizzolotto, C.; Plettner, Ch.; Ritman, J.; Roderburg, E.; Schoenmeier, P.; Schroeder, W.; Schulte-Wissermann, M.; Steinke, M.; Sun, G. J.; Ullrich, W.; Wenzel, R.; Wintz, P.; Wagner, M.; Wilms, A.; Wirth, S.; Zupranski, P.
Abstract: The reaction pp→ppω was investigated with the TOF spectrometer, which is an external experiment at the accelerator COSY (Forschungszentrum Jülich, Germany). Total as well as differential cross sections were determined at an excess energy of 93 MeV (pbeam=2950 MeV/c). Using the total cross section of (9.0±0.7±1.1) μb for the reaction pp→ppω determined here and existing data for the reaction pp→ppphi, the ratio Click to view the MathML source turns out to be significantly larger than expected by the Okubo–Zweig–Iizuka (OZI) rule. The uncertainty of this ratio is considerably smaller than in previous determinations. The differential distributions show that the ω production is still dominated by S-wave production at this excess energy, however higher partial waves clearly contribute. A comparison of the measured angular distributions for ω production to published distributions for phi production at 83 MeV shows that the data are consistent with an identical production mechanism for both vector mesons.
Keywords: Vector meson production; pp→ppω; Cross sections; Angular distributions; OZI-violation; Strangeness of the nucleon

  • Physics Letters B 647(2007)5-6, 351-357
Registration 07.06.2007 16:26, No. 10165
 
Overview of the present status of the SRF gun design and construction
Michel, P.

  • Invited lecture (Conferences):
    Workshop on Advanced Free Electron Lasers and Their Applications, 24.-25.06.2004, Taiwan, China
Registration 16.05.2007 12:05, No. 10048
 
Electron Beam Diagnostics at the ELBE Free Electron Laser
Michel, P.

  • Invited lecture (Conferences):
    Workshop on Advanced Free Electron Lasers and Their Applications, 24.-25.06.2004, Taiwan, China
Registration 16.05.2007 12:01, No. 10047
 
Design and Status of the Radiation Source ELBE and its FEL(s)
Michel, P.

  • Invited lecture (Conferences):
    Workshop on Advanced Free Electron Lasers and Their Applications, 24.-25.06.2004, Taiwan, China
Registration 16.05.2007 11:35, No. 10046
 
Emittance Compensation of a Superconducting RF Photoelectron Gun by a Magnetic RF Field
Janssen, D.; Volkov, V.
Abstract: For compensation of transverse emittance in normal conducting RF photoelectron guns a static magnetic field is applied. In superconducting RF guns the application of a static magnetic field is impossible. Therefore we put instead of a static field a magnetic RF field (TE - mode) together with the corresponding accelerating mode into the superconducting cavity of the RF gun. For a 3 _ cell cavity of the superconducting gun with frequencies f = 1.3GHz for the accelerating mode and f = 3.9 GHz for the magnetic mode and a bunch charge of 1 nC a transversal emittance of 0.5 mm mrad has been obtained. In this case the maximal field strength on the axis were Ez = 50 MV/m for the accelerating mode and Bz = 0.34 T for the magnetic mode.(This corresponds to Bs(max) = 0.22T on the surface of the cavity). Possibilities for the technical realization (input of RF power for the TE mode, tuning of two frequencies in one cavity, phase stability) are discussed.

  • Contribution to Proceeding:
    9th European Particle Accelerator Conference EPAC 2004, 05.-09.07.2004, Lucerne, Switzerland
    Contributions to the Proceedings, 9th European Particle Accelerator Conference EPAC 2004, MOPKF014, 92-9083-231-2, 330-332
Registration 15.05.2007 10:21, No. 9981
 
The Control System of Strahlungsquelle ELBE at Forschungszentrum
Leege, K.-W.
Abstract: Technisches Seminar, DESY Zeuthen, 13.03.2007 Zeuthen
Keywords: Control System of Strahlungsquelle ELBE

  • Invited lecture (Conferences):
    The Control System of Strahlungsquelle ELBE at Forschungszentrum, 13.03.2007, Zeuthen, Deutschland
Registration 15.05.2007 09:58, No. 9971
 
Universeller Gateway zum Datenaustausch zwischen dem Steuerungssystem der Strahlenquelle ELBE und den Datenaufnahmesystemen der Experimentatoren
Jainsch, R.
Abstract: Software zum Datenaustausch zwischen dem Steuerungssystem der Strahlenquelle ELBE und den Datenaufnahmesystemen der Experimentatoren

  • Lecture (others):
    Herbsttagung der Studiengruppe für Elektronische Instrumentierung im FZ Rossendorf, 27.-29.09.2004, Rossendorf, Deutschland
Registration 10.05.2007 10:07, No. 9833
 
CW Operation of the TTF-III Input Coupler
Knobloch, J.; Martin, M.; Anders, W.; Bauer, S.; Pekeler, M.; Belomestnykh, S.; Kostin, D.; Möller, W.; Büchner, A.; Büttig, H.; Gabriel, F.
Abstract: Several newly proposed superconducting linacs are designed to use TESLA technology operating CW rather than pulsed for which the system was developed. It must therefore be demonstrated that CW operation is feasible. Here we describe a series of CW tests with the TTF-III power coupler to determine the average power limit. These tests were performed on a coupler test stand both at room temperature at the FZ Rossendorf and under cryogenic operating conditions in BESSY’s HOBICAT[1] facility. An extrapolation of the measurements suggests that the coupler can handle 5 kW CW standing wave. It was also demonstrated that even higher power levels are feasible if the cooling of the inner conductor is modified.

  • Contribution to Proceeding:
    PAC Particle Accelerator Conference 2005, 16.-20.05.2005, Knoxville, TN, USA
    Proceedings of 2005 Particle Accelerator Conference, 3292-3294
Registration 07.05.2007 15:27, No. 9760
 
Diagnostics Beamline for the SRF Gun Project
Kamps, T.; Dürr, V.; Goldammer, K.; Krämer, D.; Kuske, P.; Kuszynski, J.; Lipka, D.; Marhauser, F.; Quast, T.; Richter, D.; Lehnert, U.; Michel, P.; Teichert, J.; Evtushenko, P.
Abstract: A superconducting radio-frequency photo electron injector (SRF gun) is currently under construction by a collaboration of BESSY, DESY, FZR and MBI. The project aims at the design and setup of a CW SRF gun including a diagnostics beamline for the ELBE FEL and to address R&D issues on low emittance injectors for future light sources such as the BESSY FEL. Of critical importance for the injector performance is the control of the electron beam parameters. For this reason a compact diagnostics beamline is under development serving a multitude of operation settings ranging from low-charge (77pC), low-emittance (1 mm mrad) mode to high-charge (2.5nC) operation of the gun. For these operation modes beam dynamics simulations are resulting in boundary conditions for the beam instrumentation. Proven and mature technology is projected wherever possible, for example for current and beam position monitoring. The layout of the beam profile and emittance measurement systems is described. For the bunch length, which varies between 5 ps and 50 ps, two schemes using electro-optical sampling and Cherenkov radiation are detailed. The beam energy and energy spread is measured with a 180o spectrometer.

  • Contribution to Proceeding:
    27th International Free Elektron Laser Conference FEL 2005, 21.-26.08.2005, Stanford, CA, USA
    Proceedings of the 27th International Free Electron Laser Conference 2005, 530-533
Downloads:
PDF

Registration 04.05.2007 08:12, No. 9736
 
The superconducting RF Photo Injector for ELBE
Teichert, J.; Arnold, A.; Buettig, H.; Hempel, R.; Janssen, D.; Lehnert, U.; Michel, P.; Moeller, K.; Murcek, P.; Schneider, C.; Schurig, R.; Staufenbiel, F.; Xiang, R.; Kamps, T.; Stephan, J.; Lehmann, W.-D.; Klemz, G.; Will, I.; Lipka, D.; Matheisen, A.; van der Horst, B.; vom Stein, P.; Beard, C. D.; Rogers, J. H. P.; Militsyn, B. L.

  • Poster:
    2nd Annual EUROFEL Workshop 2006, 06.-08.11.2006, Daresbury,, UK
Registration 05.02.2007 16:54, No. 9434
 
Status of ELBE radio frequency system
Büttig, H.
Abstract: The radiation source ELBE is based on a superconducting linear accelerator that can be operated in high average power mode (quasi continous wave mode, cw). Electrons are preaccelerated in a 250 keV-thermionic DC electron-gun and prebunched in a two stage RF-buncher section. Main acceleration is accompished in two 20 MeV-superconducting linear accelerator modules operating at 1,3 GHz which are cooled with liquid helium. The RF-power comes from 10 kW clystrons controled by the low level RF-system.

  • Lecture (others):
    MSL Seminar, 27.07.2006, Stockholm, Sweden
Registration 05.02.2007 13:08, No. 9432
 
Cs2Te photocathode for SRF gun in Rossendorf
Teichert, J.; Xiang, R.

  • Lecture (Conference):
    1st WorkShop on High Quantum Efficiency Photocathodes for RF Guns, 04.-06.10.2006, Milano, Italy
  • Contribution to Proceeding:
    1st Workshop on High Quantum Efficieny Photocathodes for RF guns, 04.-06.10.2006, Milano, Italy
    Proceedings of the 1st WorkShop on High Quantum Efficiency Photocathodes for RF Guns
Registration 05.02.2007 12:07, No. 9431
 
Microphonics Measurements at ELBE
Buechner, A.; Gabriel, F.; Schurig, R.; Staats, G.

  • Lecture (Conference):
    2nd Annual EUROFEL Workshop 2006, 06.-08.11.2006, Daresbury, UK
  • Poster:
    2nd Annual EUROFEL Workshop 2006, 06.-08.11.2006, Daresbury, UK
Registration 30.01.2007 10:42, No. 9394
 
Advantages of the Superconducting 3½ Cell SRF Gun in Rossendorf
Staufenbiel, F.
Abstract: This paper describes the features of the 3½ cell SRF gun from Rossendorf and the advantages and challenges of superconductivity. One advanced working regime of the SRF photo injectors is to produce short pulses with high bunch charges and low transverse emittance running in cw-mode. The quality of this electron beam is crucially for future FEL's with very short wave lengths. The main challenge is to compensate the growing transverse and longitudinal emittance with increasing bunch charges. Therefore, some procedures for emittance compensation for the 3½ cell SRF gun will be discussed.

  • Lecture (Conference):
    37th ICFA Advanced Beam Dynamics Workshop on Future Light Sources FLS 2006, 15.-19.05.2006, Hamburg, Germany
  • Contribution to Proceeding:
    37th ICFA Advanced Beam Dynamics Workshop on Future Light Sources FLS 2006, 15.-19.05.2006, Hamburg, Germany
    FLS 2006 - Proceedings
Registration 30.01.2007 09:26, No. 9391
 
BNL superconducting RF guns-technology challenges as ERL sources
Burrill, A.; Ben-Zvi, I.; Calaga, R.; Chang, X.; Hahn, H.; Kayran, D.; Kewisch, J.; Litvinenko, V.; Mcintyre, G.; Nicoletti, A.; Pate, D.; Rank, J.; Scaduto, J.; Rao, T.; Wu, K.; Zaltsman, A.; Zhao, Y.; Bluem, H.; Cole, M.; Falletta, M.; Holmes, D.; Peterson, E.; Rathke, J.; Schultheiss, T.; Todd, A.; Wong, R.; Lewellen, J.; Funk, W.; Kneisel, P.; Phillips, L.; Preble, J.; Janssen, D.; Nguyen-Tuong, V.
Abstract: The design, fabrication and commissioning of a 703.75 MHz SRF photoinjector with a retractable multi-alkali photocathode designed to deliver 0.5A average current at 100% duty factor is the present undertaking of the electron cooling group in the Collider Accelerator Division of Brookhaven National Labs. This photoinjector represents the state of the art in photoinjector technology, orders of magnitude beyond the presently available technology, and should be commissioned by 2007. The R&D effort presently underway, and the focus of this paper, will address the numerous technological challenges that must be met for this project to succeed. These include the novel physics design of the cavity, the challenges of inserting and operating a multi-alkali photocathode in the photoinjector at these high average currents, and the design and installation of a laser system capable of delivering the required 10s of watts of laser power needed to make this photoinjector operational. (c) 2005 Elsevier B.V. All rights reserved.
Keywords: energy recovery linac; high average current; superconducting RF; photoinjector design; ampere class; photocathode

  • Nuclear Instruments and Methods in Physics Research A 557(2006), 75-79
Registration 29.01.2007 15:53, No. 9387
 
Hyperon production in the channel pp -> K+ Lambda p near the reaction threshold
Abd El-Samad, S.; Bilger, R.; Böhm, A.; Brinkmann, K.-Th.; Clement, H.; Dshemuchadse, S.; Eyrich, W.; Erhardt, A.; Fanara, C.; Filippi, A.; Freiesleben, H.; Fritsch, M.; Geyer, R.; Hauffe, J.; Hassan, A.; Herrmann, P.; Hesselbarth, D.; Jakob, B.; Kilian, K.; Koch, H.; Kress, J.; Kuhlmann, E.; Marcello, S.; Marwinski, S.; Metzger, A.; Michel, P.; Möller, K.; Morsch, H. P.; Naumann, L.; Roderburg, E.; Schamlott, A.; Schönmeier, P.; Schulte-Wissermann, M.; Schroeder, W.; Steinke, M.; Stinzing, F.; Sun, G. Y.; Wächter, J.; Wagner, G. J.; Wagner, M.; Wilms, A.; Wirth, S.; Zielinski, U.
Abstract: Hyperon production in the threshold region was studied in the reaction pp→K+Λp using the time-of-flight spectrometer COSY-TOF. Exclusive data, covering the full phase-space, were taken at three different beam momenta pbeam=2.59, 2.68 and 2.85 GeV/c (corresponding to excess energies of var epsilon=85, 115 and 171 MeV). Total cross-sections were deduced to be 7.4±0.5 μb, 8.6±0.6 μb and 16.5±0.4 μb, respectively. Differential observables including Dalitz plots were obtained. From the investigation of the Dalitz plot at pbeam=2.85 GeV/c a dominant contribution of the N*(1650)-resonance to the reaction mechanism was found. In addition the pΛ-final-state interaction turned out to have a significant influence on the Dalitz plot distribution even 171 MeV above threshold.
Keywords: Associated strangeness production; Total cross-section; Angular distribution; Dalitz plot

  • Physics Letters B 632(2006)1, 27-34
Registration 26.01.2007 14:03, No. 9379
 
Status of the superconducting 3 1/2 cell SRF gun in Rossendorf
Arnold, A.; Staufenbiel, F.

  • Lecture (Conference):
    CARE Annual Meeting 2006, 15.-17.11.2006, Frascati, Rom, Italy
Registration 26.01.2007 11:14, No. 9378
 
Photocathode Laser for the Superconducting Photo Injector at the Forschungszentrum Rossendorf
Will, I.; Klemz, G.; Teichert, J.; Staufenbiel, F.
Abstract: We report on the design of the photocathode laser for a superconducting RF gun, which is presently under development at the Forschungszentrum (FZ) Rossendorf. This laser is foreseen to drive the RF gun in CW mode with up to 1 nC bunch charge. It generates pulses of 12...14 ps duration with 500 kHz repetition rate and 0.8 μJ pulse energy at 263 nm wavelength. This should provide sufficient pulse energy for generation of bunches with 1 nC charge using caesium telluride photocathodes. Due to two active modelockers in the laser oscillator, the latter operates in tight synchronism to the RF master oscillator of the linac. The laser consists of a short-pulse oscillator, a pulse picking Pockels cell, a regenerative amplifier and a wavelength conversion unit. The latter converts the infrared laser radiation to the ultra-violet (UV). This unit turns out to be a particularly critical element of such a photocathode laser driving a RF gun in CW mode.

  • Contribution to Proceeding:
    28th International Free Elektron Laser Conference FEL 2006, 27.08.-01.09.2006, Berlin, Germany
    Proceedings of FEL 2006, BESSY, 978-3-9809534-3-6, 564-566
  • Poster:
    28th International Free Electron Laser Conference FEL 2006, 27.08.-01.09.2006, Berlin, Germany
Registration 25.01.2007 10:21, No. 9372
 
3-1/2 Cell Superconducting RF Gun Simulations
Beard, C. D.; Rogers, J. H. P.; Teichert, J.; Staufenbiel, F.
Abstract: A 3-1/2 cell superconducting RF photocathode gun is being developed at Forschungszentrum Rossendorf to produce a high peak current, low emittance electron beam. This technology is essential to the realisation of many large scale facilities. The gun is designed for CW operation mode with 1 mA current and 9.5 MeV electron energy, and it will be installed at the ELBE superconducting electron linear accelerator. The gun will have a 3-1/2 cell niobium cavity operating at 1.3 GHz. The cavity consists of three cells with TESLA geometry and a specially designed half-cell in which the photocathode will be placed. Typical ERL-based projects require ~100 mA average current, and therefore suitable upgrade paths are required. Simulations have been carried out to evaluate the design and to determine suitable upgrades for higher current operation. Simulations of alternative cathode surface shapes are presented. Several couplers have been identified that can provide higher power to the cavity, whose integration and suitability has been verified. All the investigations that have identified possible solutions to higher current operation are discussed in this report.

  • Contribution to Proceeding:
    European Particle Accelerator Conference EPAC 2006, 26.-30.06.2006, Edinburgh, GB
    EPAC 2006 Proceedings, 92-9083-278-9, 2481-2483
Registration 24.01.2007 19:05, No. 9371
 
The Radiation Source ELBE at Forschungszentrum Rossendorf
Michel, P.
Abstract: The radiation source ELBE (Electron Linac of high Brilliance and low Emittance) at Forschungszentrum Rossendorf is based on a superconducting linac that produces a high power continuous wave (cw) electron beam up to 40 MeV and 1 mA. The linac is used to drive two free-electron lasers producing infrared radiation from 5 to 150 microns wavelength. Additionally, from several conversion targets MeV-bremsstrahlung (< 20 MeV) and X-rays (10-100 keV) from electron channelling are generated. In the future even neutron and positron beams will be available at ELBE. The used superconducting RF accelerator technology and details of the machine instrumentation, in particular the electron beam diagnosis will be described.

  • Lecture (Conference):
    DPG - Tagung, 27.-31.03.2006, Dresden, Germany
Registration 23.01.2007 11:22, No. 9367
 
Development of a Superconducting RF Photoinjector
Teichert, J.
Abstract: A superconducting rf photo electron injector (SRF gun) is under development at the Forschungszentrum Rossendorf. The project aims at several issues: improvement of the beam quality for the ELBE superconducting electron linac, demonstration of feasibility of this gun type, investigation of critical components, and parameter studies for future application (BESSY-FEL, 4GLS). The design layout of the SRF photo-injector, the parameters of the superconducting cavity and the expected electron beam parameters are presented. The SRF gun has a 3+1/2-cell niobium cavity working at 1.3 MHz and will be operated at 2 K. The three full cells have TESLA-like shapes whereas the half-cell has an special form obtained from numerical optimization. In the half-cell a Cs2Te photocathode is situated which will be cooled by liquid nitrogen. In 2005, the main parts for He cryostat like vacuum vessel, cryogenic and magnetic shields were fabricated. Test benches for the cathode cooling system and the cavity tuner were assembled and the measurements performed. The photo cathode preparation lab has been arranged, and the diagnostic beam line has been designed. After delivery of the Nb cavity, its rf properties were measured. The cavity was tuned and its chemical treatment is started.

  • Lecture (Conference):
    DPG - Tagung, 27.03.2006, Dresden, Germany
Registration 23.01.2007 09:50, No. 9363
 
High Peak Current Design of a superconducting Cavity for a SRF Photoinjector
Janssen, D.; Marhauser, F.; Volkov, V.
Abstract: A 1.5-cell cavity for a superconducting RF gun has been designed and a magnetic RF mode for emittance compensation is applied. For a peak current of 125 A a transverse emittance of 1.8 mm mrad has been obtained.

  • Poster:
    28 th Free Electron Laser Conference FEL 2006, 27.08.-01.09.2006, Berlin, Germany
  • Contribution to Proceeding:
    28 th Free Electron Laser Conference FEL 2006, 27.08.-01.09.2006, Berlin, Germany, 571-574
Registration 11.01.2007 08:16, No. 9246
 
Development of a prototype superconducting cw cavity and cryomodule for energy recovery
Mcintosh, P. A. Beard; Dykes, C. D.; Todd, D. M.; Belomestnykh, B.; Liepe, S.; Medjidzade, M.; Padamsee, V.; Sears, H.; Shemelin, J.; Proch, V. D.; Buechner, A.; Michel, P.; Teichert, J.; Kimura, T.; Smith, T. I.; Byrd, J.; Corlett, J. N.; Li, D.
Abstract: Energy Recovery LINAC (ERL) and LINAC-driven FEL proposals and developments are now widespread around the world. Superconducting RF (SRF) cavity advances made over the last 10 years for TESLA/TTF at 1.3 GHz, in reliably achieving accelerating gradients >20 MV/m, suggest their suitability for these ERL and FEL accelerators. Typically however, photon fluxes are maximised from the associated insertion devices when the electron bunch repetition rate is as high as possible, making CW-mode operation at high average current a fundamental requirement for these light sources. Challenges arise in controlling the substantial HOM power and in minimizing the power dissipated at cryogenic temperatures during acceleration and energy recovery, requiring novel techniques to be employed. This paper details a collaborative development for an advanced high-Q0 cavity and cryomodule system, based on a modified TESLA cavity, housed in a Stanford/Rossendorf cryomodule. The cavity incorporates a Cornell developed resistive-wall HOM damping scheme, capable of providing the improved level of HOM damping and reduced thermal load required.

  • Contribution to Proceeding:
    European Particle Accelerator Conference EPAC 2006, 26.-30.06.2006, Edinburgh, GB
    EPAC 2006 - Proceedings, 436
Registration 10.01.2007 16:08, No. 9240
 
The partial waveguide resonator of the U100-FEL at FZ Rossendorf
Freitag, M.; Schlenck, R.; Seidel, W.; Willkommen, U.; Wünsch, R.; Wustmann, B.
Abstract: The partial waveguide resonator of the U100-FEL at FZ-Rossendorf and its peculiarities are ilustrated.
Keywords: free-electron laser, waveguide, resonator, beam diagnostics

  • Contribution to Proceeding:
    28th International Free Electron Laser Conference, 27.08.-01.09.2006, Berlin, Germany
    The partial-waveguide resonator of the U100-FEL at FZ Rossendorf
  • Poster:
    28th Int. Free Electron Laser Conference, 27.08.-01.09.2006, Berlin, Germany
Registration 11.10.2006 11:28, No. 8912
 
Development of a neutron time-of-flight source at the ELBE accelerator
Klug, J.; Altstadt, E.; Beckert, C.; Beyer, R.; Freiesleben, H.; Galindo, V.; Greschner, M.; Grosse, E.; Junghans, A. R.; Légrády, D.; Naumann, B.; Noack, K.; Schilling, K. D.; Schlenk, R.; Schneider, S.; Seidel, K.; Wagner, A.; Weiss, F.-P.
Abstract: The ELBE electron beam at Forschungszentrum Rossendorf, Dresden, with energies up to 40 MeV, will be used to produce intense neutron beams. The neutron radiator consists of a liquid lead circuit where bremsstrahlung photons created by the electrons produce neutrons in (gamma,n) reactions. The short beam pulses (5 ps) provide the basis for an excellent time resolution for neutron time-of-flight experiments, giving an energy resolution of about 1 % with a flight path of 4 m. The neutron beam is shaped by a 2.4 m long collimator. The usable energy range is from 50 keV up to 10 MeV when ELBE delivers a beam repetition rate of 0.5 MHz. In this energy interval, there is a need for neutron cross section measurements relevant for the transmutation of minor actinides in nuclear waste, as well as for applications to fission and fusion reactors. The neutron flux at the sample position is 10^7 cm^-2 s^-1. Different detector types are being developed. For neutron capture gamma rays, a BaF2 scintillation detector array of 42 crystals is being constructed, whereas for neutron detection, an up to 1 m^2 large plastic scintillator wall consisting of 1 cm thick scintillation panels is being built.

  • Contribution to Proceeding:
    International Workshop on Fast Neutron Detectors and Applications, 03.-06.04.2006, Cape Town, South Africa
    Proceedings of Science, (FNDA2006) 015, Italy
  • Lecture (Conference):
    International Workshop on Fast Neutron Detectors and Applications, 03.-06.04.2006, Cape Town, South Africa
Registration 11.10.2006 11:23, No. 8911
 
Laser Gain and Intra-cavity Losses of the ELBE Mid-IR FEL
Lehnert, U.; Michel, P.; Seidel, W.; Teichert, J.; Wünsch, R.
Abstract: The the U27-FEL of the ELBE radiation source allows to choose between five mirrors with different outcoupling holes. This allows to adapt the optical resonator to the required wavelength range to ensure the needed laser gain and to optimize the outcoupled laser power. Another parameter which influences the achievable laser gain and output power is the detuning length of the optical cavity. While for CW operation often the minimum detuning point is choosen which maximizes the outcoupled power, for pulsed-mode operation about one wavelength of cavity detuning maximizes the laser gain and yields best stability of the laser. To gain some insight into the behavior of the optical resonator we have measured the round-trip losses and the net laser gain and compare both to calulations. For the measurements we have used a fast-readout MCT detector to measure the decay and rise-time of the outcoupled infrared beam caused by a 10μs break in the electron beam micro-pulse train. We show gain and loss for 5, 10 and 20μm wavelength with the typical detuning curves of an FEL.

  • Poster:
    28th Free Electron Laser Conference 2006, 27.08.-01.09.2006, Berlin, Germany
  • Contribution to Proceeding:
    28th Free Electron Laser Conference 2006, 27.08.-01.09.2006, Berlin, Germany
    Proceedings of the 28th International Free Electron Laser Conference, 339-340
Registration 20.09.2006 09:56, No. 8840
 
The Rossendorf IR-FEL ELBE
Michel, P.; Buettig, H.; Gabriel, F. G.; Helm, M.; Lehnert, U.; Schneider, Ch.; Schurig, R.; Seidel, W.; Stehr, D.; Teichert, J.; Winnerl, S.; Wünsch, R.
Abstract: The radiation source ELBE is the central research facility in the Forschungszentrum Rossendorf. The machine is based on a 40 MeV superconducting RF Linac wich can be operated up to 1mA in cwmode. After commissioning the Bremsstrahlung and the X-ray facilities in 2002, and 2003 respectively, and the first lasing of the mid- IR FEL (4-22 um) in 2004 about 7000 hours user beam-time have been provided. At present a second FEL for long IR waves (15-150 um) using a partial waveguide is under commissioning. Besides in-house users especially the IR beam is available to external users in the FELBE (FEL@ELBE) program witch is a part of the integrated activity on synchrotron and free electron laser science in the EU. In this talk the fundamental features of the ELBE IR FEL’s and the parameters demanded by users are displayed. In addition, an overview about user experimental work and important machine date like availability are shown. Future projects like the combination of the new High Magnetic Field lab with the ELBE-IR beams will be described.

  • Invited lecture (Conferences):
    28th Free Electron Laser Conference 2006, 27.08.-01.09.2006, Berlin, Germany
  • Contribution to Proceeding:
    28th Free Electron Laser Conference 2006, 27.08.-01.09.2006, Berlin, Germany
    Proceedings of the 28th International Free Electron Laser Conference, 488-491
Registration 20.09.2006 09:22, No. 8838
 
Cryomodule and Tuning System of the Superconducting RF Photo-Injector
Teichert, J.; Arnold, A.; Buettig, H.; Janssen, D.; Lehnert, U.; Michel, P.; Moeller, K.; Murcek, P.; Schneider, Ch.; Schurig, R.; Staufenbiel, F.; Xiang, R.; Kamps, T.; Lipka, D.; Klemz, G.; Lehmann, W.-D.; Stephan, J.; Will, I.
Abstract: We present the designs and report on the progress in construction and testing of the cryomodule and the tuning system for the
SRF gun. The SRF gun project, a collaboration of BESSY, DESY, MBI and FZR, aims at the installation of a high average current CW photo injector at the ELBE linac with a Nb cavity. The cryostat consists of a stainless steel vacuum vessel, a warm magnetic shield, a liquid N cooled thermal shield, and a He tank with two-phase supply tube. A heater pot in the He input port will be used for He level control. The 10 kW power coupler is adopted from ELBE module. A cooling and support systemfor the NC photo cathode has been developed and tested. It allows the adjustment of the cathode with respect to the cavity from outside. The cryomodule will be connected with the 220 W He refrigerator of ELBE and will operate at 1.8 to 2 K. The static thermal loss is expected to be less than 20W. Two tuners will be installed for separate tuning of the three TESLA cells and the half-cell. The tuners are dual spindle-lever systems with stepmotors and low-vibration gears outside the cryostat. Functionality, tuning range and accuracy have been tested in cryogenic environment.

  • Poster:
    28th Free Electron Laser Conference 2006, 27.08.-01.09.2006, Berlin, Germany
  • Contribution to Proceeding:
    28th Free Electron Laser Conference 2006, 27.08.-01.09.2006, Berlin, Germany
    Proceedings of the 28th International Free Electron Laser Conference, 575-578
Registration 20.09.2006 08:45, No. 8836
 
First RF-Measurements at the 3.5-Cell SRF-Photo-Gun Cavity in Rossendorf
Arnold, A.; Buettig, H.; Janssen, D.; Lehnert, U.; Michel, P.; Moeller, K.; Murcek, P.; Schneider, Ch.; Schurig, R.; Staufenbiel, F.; Teichert, J.; Xiang, R.; Kamps, T.; Lipka, D.; Marhauser, F.; Klemz, G.; Lehmann, W.-D.; Stephan, J.; Volkov, V.; Will, I.
Abstract: At the Forschungszentrum Rossendorf the development and the setup of the 2nd superconducting radio frequency photo electron injector (SRF-Photo-Gun) is nearly finished. One of the main attentionwas focussed at the treatment of the cavity. Their RF properties were measured at room temperature. The warm tuning was carried out considering pre-stressing and tuning range of both tuners (half cell and full cells). The adjusted field profiles and pass band frequencies of the four fundamental modes met the requirements. An external Q study of the main coupler yielded to an optimal antenna length and showed very good agreement between simulation and measurement. Furthermore the characteristics of the choke filter and both HOM filters were simulated, measured and tuned at the pi-mode frequency. The preparation (etching and rinsing) and the cold test were successfully done at DESY. The poster presents the setup for the measurements as well as a comparison of the simulated and measured results.

  • Poster:
    28th International Free Elektron Laser Conference, 27.08.-01.09.2006, Berlin, Germany
  • Contribution to Proceeding:
    28th Free Electron Laser Conference 2006, 27.08.-01.09.2006, Berlin, Germany
    Proceedings of the 28th International Free Electron Laser Conference, 567-570
Registration 20.09.2006 08:16, No. 8834
 
Pulsed RF System for the ELBE Superconducting Accelerator
Buechner, A.; Gabriel, F. G.; Buettig, H.; Lehnert, U.; Michel, P.; Schneider, Ch.; Schurig, R.
Abstract: The RF system for the ELBE accelerator was originally designed for CW mode. Although this works problem-free tests have shown that it is possible to reach higher gradients in the TESLA cavities with a pulsed RF system. The new RF system will be presented together with measurements of the achievable gradients. Roughly 30% higher gradients could now be used in pulsed mode. As positive side effects the radiation by field emission is reduced by the duty cycle and an easy in situ RF conditioning of cavities and coupler windows is possible.

  • Poster:
    European Particle Accelerator Conference, 26.-30.09.2006, Edinburgh, Scotland
Registration 19.09.2006 17:39, No. 8833
 
A Pulsed-RF High-power Processing Effect of Superconducting Niobium Cavities observed at the ELBE Linear Accelerator
Lehnert, U.; Buettig, H.; Michel, P.; Schneider, Ch.; Schurig, R.; Buechner, A.; Gabriel, F. G.
Abstract: The driver LINAC of the ELBE radiation source is built for cw operation. However, in some cases a pulsed-mode operation was desired to extend the otherwise stringent gradient limits. The main restriction results from field emission that decreases the Q of the cavities which was evaluated from measurements of the liquid helium consumption. After pulsed-mode operation with gradients exceeding the maximum cw accelerating gradients by 30–40\% a significant reduction in the field emission was observed. This in turn allows higher accelerating gradients to be used in cw as well. We attribute this behaviour to an rf-processing of the cavity surface which burns off field emitters.

  • Contribution to Proceeding:
    European Particle Accelerator Conference EPAC 2006, 26.-30.06.2006, Edinburgh, Scotland
    EPAC 2006 - Proceedings, 413-414
Registration 19.09.2006 17:26, No. 8832
 
Design of a Superconducting Cavity for a SRF Injector
Janssen, D.; Volkov, V.
Abstract: In a collaboration between BESSY, DESY, FZR, MBI and BINP a 3-1/2 cell superconducting RF electron gun is under development at the FZ - Rossendorf. The status of the project and the progress obtained in the last year is reported on this conference. The motivation for the design of a new gun cavity, presented in this paper, is the new FEL project at BESSY. This FEL is designed for a bunch charge of 2.5 nC and the transverse emittance should be comparable with that of the current SRF gun project. In order to compensate the high bunch charge a high electric field on the cavity axis is necessary. In the present paper we will present the design of a 1-1/2 cell cavity for a superconducting RF gun. The active length of the cavity (without beam tube) is 14.4 cm. For the magnetic peak field the conservative value of 130 mT is assumed. The obtained particle energy is 6.6 MeV, corresponding to an accelerating field strength of 45.6 MV/m . In the TESLA cavity the same magnetic peak field is connected with an accelerating field strength of approximately 31 MV/m. Tracking calculation of electron bunches are in progress and will be also reported.

  • Contribution to Proceeding:
    European Particle Accelerator Conference EPAC 2006, 26.-30.06.2006, Edinburgh, Scotland
    EPAC 2006 - Proceedings, 2472-2474
Registration 19.09.2006 17:03, No. 8831
 
Progress of the Rossendorf SRF Gun Project
Janssen, D.; Arnold, A.; Buettig, H.; Hempel, R.; Lehnert, U.; Michel, P.; Moeller, K.; Murcek, P.; Schneider, Ch.; Schurig, R.; Staufenbiel, F.; Teichert, J.; Xiang, R.; Kamps, T.; Lipka, D.; Marhauser, F.; Lehmann, W.-D.; Stephan, J.; Volkov, V.; Will, I.
Abstract: In this paper we report the status and the progress of the superconducting RF gun project in Rossendorf. The gun is designed for cw operation mode with 1 mA current and 10 MeV electron energy. The cavity consists of three cells with TESLA geometry, a special designed half-cell in which the photo cathode will be inserted and a choke filter, which prevents the leakage of RF power by the coaxial line between the cathode and the cavity cell. A double tuner allows the tuning of the half-cell and the TESLA cells separately. In 2005 the fabrication of two cavities with RRR300 and RRR40 was finished. We present the results of the field measurement and the warm tuning of the cavity cells as well as the tuning and performance measurement of the choke filter. The fabrication of the double tuner has been also finished. In a test bench we measured the properties of the tuner (tuning range, resolution) at LN2 temperature. Further activities concern the diagnostic beam line of the gun, the new cathode preparation and cathode transfer system, the driver laser and the LHe transfer line.

  • Contribution to Proceeding:
    European Particle Accelerator Conference EPAC 2006, 26.-30.06.2006, Edinburgh, Scotland
    EPAC 2006 - Proceedings, 2469-2471
  • Poster:
    10th biennal European Particle Accelerator Conference EPAC 2006, 26.-30.06.2006, Edinburgh, Scotland, UK
Registration 19.09.2006 16:48, No. 8830
 
FELBE: a new infrared free-electron-laser user facility
Helm, M.; Michel, P.
Abstract: no abstract available
Keywords: free-electron laser

  • Notiziario Neutroni e Luce di Sincrotrone 11(2006)2, 33-35
Registration 07.08.2006 16:22, No. 8686
 
Sachsens größte Forschungsinvestition Die Strahlungsquelle ELBE im Forschungszentrum Rossendorf
Michel, P.
Abstract: kein Abstract vorhanden

  • Invited lecture (Conferences):
    Symposium, 21.04.2005, Dresden, Germany
Registration 07.03.2006 14:20, No. 8317
 
The Radiation Source ELBE and its Research Programm in Nuclear Physics
Lehnert, U.
Abstract: kein Abstract vorhanden

  • Invited lecture (Conferences):
    Third Sandanski Coordination Meeting on Nuclear Science, 26.-30.09.2005, Albena, Bulgary
Registration 07.03.2006 13:53, No. 8316
 
Forschungszentrum Rossendorf "Status report of FZR activities" / Status of Cathode System in FZR
Teichert, J.; Xiang, R.
Abstract: kein Abstract vorhanden

  • Lecture (Conference):
    CARE Collaboration Meeting, 23.-25.11.2005, CERN, Switzerland
Registration 31.01.2006 08:19, No. 8148
 
The Superconducting photoinjector at Rossendorf - Present status of the Rossendorf Superconducting RF Photo injector development
Teichert, J.
Abstract: kein Abstract vorhanden

  • Invited lecture (Conferences):
    CARE Collaboration Meeting, 23.-25.11.2005, CERN, Switzerland
Downloads:
PDF

Registration 30.01.2006 17:00, No. 8147
 
Field profile measurement and tuning of the 3½ cell SRF-gun
Arnold, A.; Büttig, H.; Janssen, D.; Teichert, J.; Murcek, P.
Abstract: kein Abstract vorhanden

  • Poster:
    1st Annual EUROFEL Workshop 2005, 07.-09.11.2005, Orsay, France
Downloads:
PDF

Registration 13.01.2006 15:57, No. 8041
 
Test of the photocathode cooling system of the 3½ cell SRF gun
Staufenbiel, F.; Büttig, H.; Evtushenko, P.; Janssen, D.; Lehnert, U.; Michel, P.; Möller, K.; Schneider, C.; Schurig, R.; Teichert, J.; Xiang, R.; Stephan, J.; Lehmann, W.-D.; Kamps, T.; Lipka, D.; Will, I.; Volkov, V.
Abstract: This paper presents results of the photocathode cooling system test of the 3½ cell SRF gun at the Forschungszentrum Rossendorf. The SRF gun will produce short electron pulses with high bunch charges and low transverse emittance. The requirement for the superconducting electron linear accelerator in Rossendorf (ELBE) is to provide a low emittance electron beam up to 1mA current and 9.5 MeV energy. Additionally, it will easily operate in continuous wave (cw) mode because of the low RF power losses in the superconducting material. Therefore, the normal conducting copper cathode must be cooled by liquid nitrogen in order to preserve the temperature of the cavity at 2.2 K. The estimated power input from the RF field into the cathode could be more than 10 W [1]. First results of temperature measurements of the photo cathode respectively from the cooling system at a heat load up to 30 W are presented.

  • Physica C 441(2006)1-2, 216-219
Registration 11.01.2006 14:24, No. 8013
 
Review of Superconducting RF Guns
Janssen, D.; Büttig, H.; Lehnert, U.; Michel, P.; Murcek, P.; Schneider, C.; Schurig, R.; Teichert, J.; Xiang, R.; Staufenbiel, F.; Stephan, J.; Volkov, V.
Abstract: In the first topic the superconducting RF (SRF) photo-injector projects are reviewed. The DC SC photo-injector at the Peking University Accelerator Facility, the all-niobium SRF gun of Brookhaven and the high current SRF photo-injector project of AES and Brookhaven are discussed. Special attention is paid to the project of the FZ Rossendorf. The experimental set-up with a 1.3 GHz half-cell cavity has demonstrated the stable operation of a SRF photoelectron gun for the first time. The manufacture and the warm tuning of two 3 1/2 cell niobium cavities for the new photo-injector project are finished. A new cryostat with a special tuning and cathode transfer system has been designed. The status of manufacture for different components is shown. In future it is planed to operate this SRF gun with an energy of 9.5 MeV as a low-emittance photo-injector for the ELBE accelerator. In the second topic of the review some special points are discussed, which are specific for superconducting RF guns. The advantages and disadvantages of different shapes for the first cavity cell (gun cell) are discussed. Different kinds of photo-cathodes (normal conducting, superconducting, all niobium) and their integration into a superconducting cavity are explained. Different possibilities (RF focussing, magnetic RF field (TE - mode), static magnetic field outside the cavity) are discussed for beam focussing and emittance compensation inside the superconducting cavity.

  • Invited lecture (Conferences):
    12th International workshop on RF Superconductivity (SRF 2005), 10.-15.07.2005, Ithaca, NY, USA
Registration 15.11.2005 18:18, No. 7837
 
Status of the 3 1/2 Cell SRF Gun Project in Rossendorf
Staufenbiel, F.; Büttig, H.; Evtushenko, P.; Janssen, D.; Lehnert, U.; Michel, P.; Schneider, C.; Schurig, R.; Teichert, J.; Xiang, R.; Möller, K.; Stephan, J.; Lehmann, W.-D.; Kamps, T.; Lipka, D.; Will, I.; Volkov, V.
Abstract: This paper describes the current status of the 3 1/2 cell SRF gun. The SRF photo injector will produce short pulses with high bunch charges and low transverse emittance like the traditional photo injector. The requirement for the ELBE superconducting electron linear accelerator is to provide low emittance electron beam with 1 mA current and 9.5 MeV energy. Additionally, it will easily operate in the CW-mode caused by the low RF power losses in the superconducting material. This is an exceptional property of the mid infrared ELBE-FEL to work in such a regime. Therefore, the normal conducting copper cathode must be cooled by liquid N2 in order to preserve the temperature of the cavity at 2 K. The estimated power input from the RF field into the cathode amounts 10 W. First results of temperature distributions on the cathode respectively the cooling system by a heat load of 10 W are presented.

  • Contribution to Proceeding:
    12th International Workshop on RF Superconductivity (SRF 2005), 10.-15.07.2005, Ithaca, N.Y., USA
    TuP23, 30-30
  • Poster:
    12th International workshop on RF Superconductivity SRF 2005, 10.-15.07.2005, Cornell University campus, Ithaca, NY, USA
Downloads:
Poster Nr. TuP23, PDF

Registration 15.11.2005 17:45, No. 7835
 
Field Profile Measurement of the 3 1/2 Cell SRF Gun
Arnold, A.; Büttig, H.; Janssen, D.; Teichert, J.; Murcek, P.
Abstract: The paper describes the development of a fully PC-controlled bead-pull measurement device based on LabView software. The device is part of a cavity tuning test stand and has been used successfully to measure the field profile and the shunt impedance of the prototype Nb-cavities for the 3 1/2 cell SRF-Gun project at FZ-Rossendorf.

  • Poster:
    12th International workshop on RF Superconductivity (SRF 2005), 10.-15.07.2005, Cornell University, Ithaca, N.Y., USA
Downloads:
TuP22, page 29, Abstracts PDF

Registration 15.11.2005 17:15, No. 7834
 
Status and Future Prospects of SRF gun developments
Teichert, J.
Abstract: Most of the proposed electron accelerator projects for FELs, ERLs, or 4th generation light sources require electron beams with an unprecedented combination of high-brightness, low emittance and high average current. In all of the projects photo guns will be applied: DC-photoguns, normal conducting RF photoguns (NC-guns), and superconducting RF photoguns (SRF-guns). While the concepts of DC- and NC-guns are well proofed, the SRF gun development still possesses a high risk. Challenges are the thermal and contaminant isolation needed between the cathode and superconducting cavity, the choice of the right photocathode and its life time, the difficulty of coupling high-average power into the gun, and beam excitation of higher order cavity modes. But in combination with SRF-linacs, the SRF-guns are best solution for high current and CW operation is simply possible. Thus, several R&D projects of SRF-gun have been launched. The talk will give an overview of the history and progress of the SRF-gun development. In detail the technical concept, performance, and status of the Rossendorf superconducting rf gun project, a collaboration of BESSY, DESY, MBI and FZR, will be presented.

  • Invited lecture (Conferences):
    36th ICFA Advanced Beam Dynamics Workshop Nanobeam 2005, 17.-21.10.2005, Kyoto, Japan
Registration 08.11.2005 15:27, No. 7814
 
Diagnostic Tools for Operation and Optimization of the ELBE-FEL
Michel, P.; Evtushenko, P.; Lehnert, U.; Schneider, C.; Schurig, R.; Teichert, J.; Seidel, W.; Wohlfarth, D.
Abstract: A FEL in the mid infrared range is one of the applications of the ELBE cw-electron accelerator. The successful operation of the lasing process for the different wavelength is mainly determined by the alignment of the optical cavities, the bunch length and the energy spread of the electron beam so as the transversal adjustment of the beam through the FEL. The energy spread and the bunch length of the electron beam have their minima at different phase conditions of the accelerator. For various energy settings of the accelerator a special adjustment of both parameters has to be found for the lasing process. The presentation describes the diagnostic tools used at ELBE for the correct alignment of the optical cavity, the steering of the electron beam through the FEL and the adjustment of the electron beam parameters with respect to energy spread and bunch length.

  • Poster:
    27th International Free Electron Laser Conference 2005, 21.-26.08.2005, Stanford, California, USA
  • Contribution to Proceeding:
    27th International Free Electron Laser Conference 2005, 21.-26.08.2005, Stanford, CA, USA
    Proceedings of the 27th International Free Electron Laser Conference,: JACoW / eConf C0508213, 102-104
Downloads:
ID: 1406 - MOPP032 PDF

Registration 07.09.2005 14:24, No. 7633
 
Optical Beam Properties and Performance of the MID-IR FEL at ELBE
Lehnert, U.; Michel, P.; Teichert, J.; Seidel, W.; Stehr, D.; Wohlfarth, D.; Wünsch, R.
Abstract: First lasing of the mid-infrared free-electron laser at ELBE was achieved on May 7, 2004. Since then stable lasing has been achieved in the IR range from 4 to 22~μm using electron beam energies from 15 to 35~MeV. At all wavelengths below 20~μm a cw optical power higher than 1~W can be produced with an electron beam of 50~pC bunch charge or less. The optical pulse width at its minimum (2.2~ps measured at 17~μm) resembles the typical electron bunch length of 2~ps without bunch compression but can be increased by detuning the optical cavity. The optical bandwidth was in all cases close to the fourier limit.

  • Poster:
    27th International Free Electron Laser Conference 2005, 21.-26.08.2005, Stanford, California, USA
  • Contribution to Proceeding:
    27th International Free Electron Laser Conference, 21.-26.08.2005, Stanford, CA, USA
    Proceedings of the 27th International Free Electron Laser Conference: JACoW / eConf C0508213, 286-287
Registration 07.09.2005 13:23, No. 7632
 
Progress of the Rossendorf SRF Gun Project
Teichert, J.; Arnhold, A.; Buettig, H.; Janssen, D.; Lehnert, P.; Michel, P.; Moeller, K.; Schneider, C.; Staufenbiel, F.; Xiang, R.; Kamps, T.; Lipka, D.; Marhauser, F.; Volkov, V.; Stephan, J.; Lehman, W.-D.; Will, I.
Abstract: A superconducting rf photo electron injector (SRF gun) is under development at the Forschungszentrum Rossendorf. The project aims at several issues: improvement of the beam quality for the ELBE superconducting electron linac, demonstration of feasibility of this gun type, investigation of critical components, and parameter studies for future application (BESSY-FEL, 4GLS). In 2005, a substantial progress has been made. The two 3.5-cell niobium cavities for the gun have been delivered from the company ACCEL. The main parts for gun cryostat like vacuum vessel, cryogenic and magnetic shields are ready. Test benches for the cathode cooling system and the cavity tuner are being assembled. The photo cathode preparation lab has been arranged, and the diagnostic beam line has been designed (see T. Kamps et al., this conference). After delivering the gun cavities, their rf properties are being measured at room temperature and the warm tuning is being carried out. The set-up for this treatment and measurement as well as the results will be presented.

  • Poster:
    27th International Free Electron Laser Conference 2005, 21.-26.08.2005, Stanford, California, USA
  • Contribution to Proceeding:
    27th International Free Electron Laser Conference 2005, 21.-26.08.2005, Stanford, CA, USA
    Proceedings of the 27th International Free Electron Laser Conference: JACoW / eConf C0508213, 534-537
  • Poster:
    1 st Annual EUROFEL Workshop 2005, 07.-09.11.2005, Orsay, France
Registration 06.09.2005 15:44, No. 7631
 
Vector Meson Production in Collisions of Nucleons.
Brinkmann, K.; Abdel-Bary, M.; Abdel-Samad, S.; Clement, H.; Doroshkevich, E.; Dshemuchadse, S.; Dutz, H.; Ehrhardt, K.; Erhardt, A.; Eyrich, W.; Filippi, A.; Freiesleben, H.; Fritsch, M.; Georgi, J.; Gillitzer, A.; Gonser, P.; Jakel, R.; Karsch, L.; Kilian, K.; Koch, H.; Kress, J.; Kuhlmann, E.; Marcello, S.; Meyer, W.; Michel, P.; Morsch, H. P.; Moller, K.; Mortel, H.; Naumann, L.; Pinna, L.; Pizzolotto, C.; Roderburg, E.; Schamlott, A.; Schonmeier, P.; Schroeder, W.; Schulte-Wissermann, M.; Sefzick, T.; Steinke, M.; Stinzing, F.; Sun, G. Y.; Ucar, A.; Ullrich, W.; Wagner, G. J.; Wagner, M.; Wilms, A.; Wintz, P.; Wirth, S.; Wustner, P.; Zupranski, P.
Abstract: The production of vector mesons in collisions between nucleons is studied in order to address a variety of issues concerning nucleon-nucleon interaction, reaction mechanism and properties of baryons. These studies are summarized with emphasis on the most recent experiments at the Time-of-Flight spectrometer TOF and results obtained at the COoler SYnchrotron COSY in Jülich. While currently the open questions regarding the so-called OZI violation, its relation to the meson exchange picture and the relative importance of contributions to the production mechanism from various channels within this formalism are still unresolved, the present-day experiments hold the potential to clarify the situation greatly. Possible extensions of the experimental program on vector mesons using 4π detection techniques for charged as well as neutral particles, in particular π0, are discussed.
Keywords: Nucleon-nucleon interaction; vector meson production; reaction mechanism and resonances

  • International Journal of Modern Physics A 20(2005)2-3, 427-435
Registration 05.09.2005 13:42, No. 7626
 
A Far-Infrared FEL for the Radiation Source ELBE
Grosse, E.; Lehnert, U.; Michel, P.; Schlenk, R.; Seidel, W.; Wolf, A.; Willkommen, U.; Wohlfarth, D.; Wünsch, R.
Abstract: After successfully commissioning the mid‐infrared FEL (U27) and adjoining a second accelerator unit (up to 35 MeV) at ELBE we have modified our plan how to produce radiation in the far infrared.To ensure the continuous variation of the wavelength up to 150 microns we want to complement the U27 undulator by a permanent magnet undulator with a period of 100 mm (U100). The minimum gap of 24 mm and the hybrid construction consisting of Sm/Co magnets and soft iron poles ensures sufficient radiation resistance and allows rms undulator parameters up to 2.7. The large field variation allows us to cover the whole wavelength range by only two different electron energies (e.g. 20 and 35 MeV). To reduce the transverse beam size we use a partial waveguide which is 10 mm high and wide enough to allow free propagation inhorizontal direction. It spans from the last quadrupole in front of the undulator up to the downstream mirror and is somewhat longer than 8 m. To minimize the coupling losses between free propagation and the waveguide mode appropriate bifocal resonator mirrors will be sed. Detailed calculations and computer simulations predict an outcoupled laser power of roughly 35 W around 40 microns and 20 W at150 microns.
Keywords: undulator, free-electron laser, waveguide, radiation source ELBE

  • Poster:
    27th Int. Free Electron Laser Conference, 21.-26.08.2005, Palo Alto, USA
  • Contribution to Proceeding:
    27th Free Electron Laser Conference, 21.-26.08.2005, Palo Alto, USA
    Proceedings of the 27th International Free Electron Laser Conference, 290-292
Registration 10.08.2005 15:26, No. 7584
 
Status of the 31/2 cell SRF gun project in Rossendorf
Xiang, R.; Büttig, H.; Evtushenko, P.; Janssen, D.; Lehnert, U.; Michel, P.; Schneider, C.; Schurig, R.; Teichert, J.; Möller, K.; Lehmann, W.-D.; Stephan, J.; Kamps, T.; Lipka, D.; Will, I.; Volkov, V.
Abstract: In the paper, we report on the status and progress of the superconducting RF gun project in Rossendorf. The gun is designed for cw operation mode with 1 mA current and 9.5 MeV electron energy, and it will be installed at the ELBE superconducting electron linear accelerator. The gun will have a 3½ cell niobium cavity operating at 1.3 GHz. The cavity consists of three cells with TESLA geometry and a specially designed half-cell in which the photocathode will be placed. The production of two Nb cavities, with RRR 300 and 40 respectively, has be finished at the beginning of 2005. After delivery, the RF tests will be performed and the preparation of the cavities will be started. At the same time, the design of the cryostat and the fabrication of its components are already finished. Further activities are the design of the diagnostic beam line, the testing of the new photocathode preparation system, and the upgrade of the 262 nm driver laser system.

  • Poster:
    Particle Accelerator Conference 2005, 16.-20.05.2005, Knoxville, TN, USA
  • Contribution to Proceeding:
    Particle Accelerator Conference 2005, 16.-20.05.2005, Knoxville, Tennessee, USA
    Proceedings of 2005 Particle Accelerator Conference, 1081-1083
Downloads:
WPAP007 PDF
Proceedings PDF

Registration 25.07.2005 13:57, No. 7560
 
Axial RF power input into photocathode electron guns
Janssen, D.; Volkov, V.; Bluem, H. P.; Todd, A. M. M.
Abstract: We discuss the coaxial power input in normal and superconducting RF (SRF) photoinjector cavities. Upstream coaxial power input has been previously used at the PITZ facility where the output beam tube is an intrinsic part of the coaxial transmission line into the gun. In this paper, we describe coaxial coupling from the cathode side of the gun. For normal conducting RF guns, in addition to the advantage from symmetric coupling, an emittance compensation solenoid can now be positioned close to the gun cavity to deliver optimal transverse emittance. Beam dynamics calculations demonstrate 0.8 mm-mrad at 1 nC in X-band. For an SRF gun, we present a design for coaxial input around the cathode using a superconducting coupling cell. This cell matches the external quality factor of the gun for different beam powers and there is no RF loss associated with the axial gap of the cathode. The heat input into the coaxial feed and the surface field of the coupler are discussed. For a 1.3 GHz half-cell gun cavity with stored energy of 6.6 J, a 2.5 MeV electron beam can be delivered with a peak accelerating field of 50 MV/m. At 10 mA, the external Q is 2.1 x 106 and the coaxial line power loss that must be cooled is 28 W.

  • Lecture (Conference):
    PAC Particle Accelerator Conference 2005, 16.-21.05.2005, Knoxville, TN, USA
  • Contribution to Proceeding:
    Particle Accelerator Conference 2005, 16.-20.05.2005, Knoxville, Tennessee, USA
    Proceedings of 2005 Particle Accelerator Conference, MOPB011, ISBN 0-7803-8860-7, 743-745
Registration 13.06.2005 08:39, No. 7458
 
Annual Report 2003/04 - Radiation Source ELBE
Lehnert, U. (Editor)
Abstract: no abstract available

  • Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-428 2005
Downloads:
Volltext PDF

Registration 03.05.2005 11:50, No. 7356
 
Die Strahlungsquelle ELBE im Forschungszentrum Rossendorf Konzept und erste Betriebserfahrungen
Michel, P.
Abstract: Der Elektronenbeschleuniger ELBE (Elektronenbeschleuniger mit hoher Brillanz und geringer Emittanz) [1] im Forschungszentrum Rossendorf wird nach seiner endgültigen Fertigstellung elektromagnetische Strahlung, Neutronen, Positronen sowie Elektronen für die Forschung liefern. Die Vielfalt und die hervorragenden Eigenschaften dieser Sekundärstrahlung machen ELBE zum zentralen und verbindenden Großgerät der Institute im Forschungszentrum Rossendorf. Ein 40 MeV, 1mA Elektronenbeschleuniger dient als Treiber für die verschiedenen Arten von Sekundärstrahlung.

  • Lecture (Conference):
    SEI - Herbsttagung (Studiengruppe für Elektronische Instrumentierung), 27.-29.09.2004, Forschungszentrum Rossendorf, Dresden, Germany
  • Contribution to Proceeding:
    Herbsttagung der SEI Studiengruppe für Elektronische Instrumentierung, 27.-29.09.2004, FZ Rossendorf, Dresden, Germany
    Bericht der Herbsttagung der Studiengruppe für Elektronische Instrumentierung, Berlin: HMI-B 600, ISSN 0936 - 0891, 2-8
  • Contribution to WWW:
    http://www.hmi.de/bereiche/I/DS/sei/archiv/2004-09/vortrag/michel_text.pdf
Downloads:
Bericht Herbsttagung Remote resource

Registration 01.04.2005 14:26, No. 7303
 
Die Strahlungsquelle ELBE im Forschungszentrum Rossendorf
Michel, P.
Abstract: Die Strahlungsquelle ELBE (Elektronenbeschleuniger mit hoher Brillanz und niedriger Emittanz) im Forschungszentrum Rossendorf wird nach ihrer vollständigen Inbetriebnahme ein breites Spektrum von Sekundärstrahlung für die Forschung liefern. Im elektromagnetischen Bereich werden an ELBE intensive und polarisierte Bremsstrahlung (Maximalenergie 20 MeV), monochromatische Röntgenstrahlung (10-100 keV) und Infrarotstrahlung aus Freie-Elektronen-Lasern (6-400 meV) produziert. Darüber hinaus werden gepulste Neutronen und monoenergetische Positronen als Sekundärteilchenstrahlen und ein direkter Elektronenstrahl mit hoher Strahlleistung bis zu 40kW zur Verfügung stehen. Als Treiber für die Sekundärstrahlungserzeugung dient ein supraleitender Hochfrequenzelektronenbeschleuniger mit einer Maximalenergie von 40 MeV und einem mittleren Strahlstrom von 1 mA. ELBE wurde im Rahmen einer Projektgruppe des FZR konzipiert und aufgebaut. Die vollständige Inbetriebnahme soll im Jahre 2005 abgeschlossen sein. Mit ELBE steht dem Forschungszentrum Rossendorf und der Forschungsgemeinschaft insgesamt ein leistungsfähiges und modernes Instrument zu Verfügung. Das breite Spektrum von Strahlung und die exzellenten Strahleigenschaften eröffnen einer Vielzahl von Forschungsrichtungen, experimentellen Techniken und technologischen Anwendungen neue Möglichkeiten. Derzeit sind beispielsweise Experimente zur Untersuchung der Kernstruktur, der biologischen Wirksamkeit von Röntgenstrahlung, der Dynamik von metallischen Mehrphasenströmungen, von Halbleiter-, Festkörper- und Quantenstrukturen sowie von nuklearen Prozessen in Fusionsreaktormaterialien geplant. Der Vortrag soll die Parameter und die potentiellen Möglichkeiten der Strahlungsquelle ELBE aufzeigen und für weitere Anwendungen werben.

  • Contribution to WWW:
    P. Michel et al., DACH-Jahrestagung, Zerstörungsfreie Materialprüfung, ZfP in Forschung, Entwicklung und Anwendung, Kurzfassungen der Vorträge und Plakatbeiträge, Vortrag 50, Sitzung E3, 17. – 19.05.2004, Salzburg, Austria: http://www.dgzfp.de/tagungen/Jahrestagung/Salzburg/KuFa2004.pdf
  • Lecture (Conference):
    DACH-Jahrestagung, Zerstörungsfreie Materialprüfung ZfP in Forschung, Entwicklung und Anwendung, 17.-19.05.2004, Salzburg, Austria
Registration 01.04.2005 13:37, No. 7302
 
Diagnostics at the ELBE Bremsstrahlung Facility
Michel, P.; Evtushenko, P.; Lehnert, U.; Schurig, R.; Teichert, J.; Schilling, K.-D.
Abstract: The ELBE (Electron Linear accelerator with high Brilliance and low Emittance) machine is currently under transition from commissioning to regular user operation. The linac produces an up to 40 MeV, 1 mA (CW) electron beam which is used to generate various kinds of secondary radiation. While IR-FEL and X-ray facilities are still under construction, comprehensive nuclear physics experiments at the bremsstrahlung facility have been conducted. Both, to meet the experimentor’s demands on beam quality, stability and reproducibility and to ensure a safe operation of the machine, several diagnostic elements, such as backward OTR viewers, radiator temperature diagnostics, stripline detectors to monitor the beam incidence angle on the radiator and a four-quadrant loss monitor were developed, installed and tested. These elements are described and results are presented in this paper.

  • Poster:
    11th Beam Instrumentation Workshop, 03.-06.05.2004, Knoxville, TN, USA
  • Contribution to Proceeding:
    Eleventh Beam Instrumentation Workshop 2004, 03.-06.05.2004, Knoxville, Tennessee, USA
    Beam Instrumentation Workshop 2004, Melville, N. Y., USA: American Institute of Physics, 0-7354-0214-0, 128-132
Registration 01.04.2005 13:16, No. 7301
 
The ELBE accelerator and the SRF Gun project
Teichert, J.
Abstract: leider nicht vorhanden

  • Lecture (Conference):
    EUROFEL Kick - Off Meeting 2005, 17.-18.01.2005, Hamburg, Germany
Registration 01.04.2005 12:57, No. 7300
 
Technology Challenges for SRF Guns as ERL Sources in View of Rossendorf work
Janssen, D.; Büttig, H.; Evtushenko, P.; Lehnert, U.; Michel, P.; Möller, K.; Murcek, P.; Schneider, C.; Schurig, R.; Staufenbiel, F.; Teichert, J.; Xiang, R.; Stephan, J.; Lehmann, W.-D.; Kamps, T.; Lipka, D.; Volkov, V.; Will, I.
Abstract: After discussing the demands on ERL injectors for different projects, we will discuss the technological challenges and the obtained solutions for different parts of the SRF gun. The first point is the shape of the gun cavity and the tuning system. An essential parameter is the length of the first cell, which is determined by the condition, that the field strength at the cathode has a maximal value at the moment of electron emission. If the cavity consists of different cells, as the 3 ½ cell cavity of the Rossendorf gun, two independent tuning systems are necessary. An essential point is the installation of a normal conducting cathode inside a superconducting cavity. The cathode must be isolated by a vacuum gap, it must be alignable and exchangeable from outside of the cryostat and on has to cool down it to LN2 temperature. The next point of discussion is the RF choke filter, which prevents the leakage of RF power, caused by the coaxial between the cathode and the cavity. Different solutions will be shown. In order to focus the beam and to avoid the increasing of transverse emittance a static magnetic field is applied immediately after the cathode in normal conducting RF guns. For a superconducting cavity three possibilities exist to reach the same effect: The first is to put a solenoid after the cavity and outside the cryostat. The second one is the so called RF focussing, where near the cathode a radial component of the RF field is created, which focus the beam. The most elegant way is to put an additional magnetic RF mode into the cavity. It is shown, that for emittance compensation the phase of this mode is not relevant and the amplitude is inside the limit, given by the maximal surface field strength. Especially for high current guns the input of RF power could be a problem. We will show the limits of the RF coupler in the current Rossendorf project and discuss the idea of a coaxial input of RF power from the cathode side of the gun, where the coaxial between the cathode and the cavity is the main part of the RF input coupler. In the last point we discuss the experimental results obtained in Rossendorf and present the status of the current project.

  • Nuclear Instruments and Methods in Physics Research A 557(2006), 80-86
  • Invited lecture (Conferences):
    32nd Advanced ICFA Beam Dynamics Workshop on Energy Recovering Linacs ERL 2005, 19.-23.03.2005, Newport News, USA
Downloads:
Lecture Remote resource

Registration 31.03.2005 13:24, No. 7294
 
Status of superconducting module development suitable for cw operation: ELBE cryostats
Teichert, J.; Büttig, H.; Michel, P.; Lehnert, U.; Schneider, C.; Möller, K.; Büchner, A.; Gabriel, F.; Stephan, J.; Winter, A.
Abstract: For the ELBE electron linear accelerator a superconducting accerating module was developed and is now in routine operation. The cryostat contains two TESLA cavities (1.3 GHz) and is designed for cw operation with an accelerating gradient of 10 MV/m and a maximum average beam current of 1 mA. For the power RF two 10 kW klystrons are used. Special tuners, power couplers, low level rf control, cryogenic control systems and safety systems were developed. We will discuss engineering design, operation parameters and our experience with the module.

  • Nuclear Instruments and Methods in Physics Research A 557(2006), 239-242
  • Invited lecture (Conferences):
    32nd Advanced ICFA Beam Dynamics Workshop on Energy Recovering Linacs ERL 2005, 19.-23.03.2005, Newport News, USA
Registration 31.03.2005 12:27, No. 7293
 
First Lasing at the ELBE mid-IR FEL
Michel, P.; Evtushenko, P.; Lehnert, U.; Dekorsy, T.; Gabriel, F.; Grosse, E.; Helm, M.; Krenz, M.; Seidel, W.; Wohlfarth, D.; Wolf, A.; Wünsch, R.
Abstract: First lasing of the mid infrared FEL at ELBE was achieved on May 7, 2004. The Radiation Source ELBE at the Forschungszentrum Rossendorf in Dresden is currently under transition from commissioning to regular user operation. Presently the electron linac produces an up to 18 MeV, 1 mA (cw) electron beam which is alotted to generate various kinds of secondary radiation. After the successful commissioning of the bremsstrahlung and channeling-X-ray facilities during 2003 stable lasing has now been observed in the IR range (15 to 22 μm). The oscillator FEL is equipped with two planar undulator units, both consisting of 34 hybrid permanent magnet periods of 27.3 mm (Krms = 0.3 - 0.8). The distance between the two parts is variable and the gaps can be adjusted and tapered independently. At 19.6 µm an optical power of 3W was out-coupled in a macro pulse of 0.6 ms duration using an electron beam energy of 16.1 MeV and an energy spread of less than 100 keV; the micropulse charge was 50 pC and its width slightly above 1ps. With the installation of a second acceleration module for additional 20 MeV smaller wavelengths will become available in the near future.

  • Lecture (Conference):
    26th International Free Electron Laser Conference FEL 2004, 29.08.-03.09.2004, Trieste, Italy
  • Contribution to Proceeding:
    26th International Free Electron Laser Conference and 11th FEL Users Workshop, 29.08.-03.09.2004, Trieste, Italy
    Proceedings of the 26th International Free Electron Laser Conference and 11th FEL Users Workshop, MOAIS04, Trieste: Graphart ts, 88-87992-02-9 (CD), 88-87992-02-9 (Book), 8-13
Downloads:
Volltext Proceedings 58,6 MB Remote resource

Registration 31.03.2005 08:32, No. 7288
 
Estimation of field amplitudes during the operation of the 1.5 cell photoelectron RF gun of the PITZ collaboration
Janssen, D.
Abstract: The present paper discuss the posibility to obtain information about the field flatness of a 1.5 cell normal conducting RF gun cavity during the running of the gun. By measurements of the microwave network parameters at room temperature and by measurement of the passband frequencies in the running regime of the gun it is possible to estimate the perturbation of field flatness, caused by an inhomogeneous temperature distribution.

  • Other report:
    Hamburg: DESY, 2005
    7 Seiten
Registration 24.02.2005 13:34, No. 7183
 
CW test of the TTF-III input coupler at Rossendorf
Bauer, S.; Belomestnykh, S.; Buechner, A.; Büttig, H.; Gabriel, F.; Knobloch, J.; Moeller, W.-D.; Pekeler, M.
Abstract: While many laboratories plan to use TESLA-like cavities and/or cryomodules in CW regime, the TTF-III coupler [1] has never been tested in CW mode to find out what is its average power limit and what parts of the coupler would require upgrade/redesign for higher average power operation. ACCEL, BESSY, Cornell, DESY and Rossendorf agreed to collaborate on such a test of the TTF-III coupler. ACCEL manufactured one TTF-III coupler free of charge and assembled it on the test stand in clean-room condition. DESY provided the test stand, some additional hardware and its “know-how” in testing TTF-III couplers. Cornell provided IR viewports, instrumentation feedthroughs and its expertise and help during the coupler test and tried to coordinate joint efforts. BESSY participated in the test and offered a follow-up test in the new HoBiCaT horizontal test facility [2]. The test happened at Rossendorf at their 10 kWCW klystron test transmitter from June 14 to June 18.

  • Other report:
    ERL - Report ERL 04-10, 2004
Registration 10.12.2004 11:56, No. 6938
 
Operation Experience with the ELBE Helium Plant
Schneider, C.
Abstract: The superconducting linear accelerator ELBE has a 200W at 1.8 K cryogenic plant. Two cold compressors are used for recompression of the Helium at the 4 K level and for stabilising the pressure in the accelerator cryostat. The talk will give an overview over the ELBE cryogenic system and will focus on the operation experience with the cold compressor system and the filling modes of the cryostat. Specific problems of the ELBE Helium plant concerning purity, maintenance and reliability will be discussed.

  • Lecture (Conference):
    Conference Cryogenics Operations 2004, Jefferson Laboratory, 30.03.-02.04.2004, Newport News, USA
Registration 09.12.2004 08:56, No. 6937
 
Hochfrequenz-Elektronenquelle
Janssen, D.
Abstract: Der Erfindung liegt die Aufgabe zugrunde, die Erzeugung eines Elektronenstrahls mit einer extrem großen mittlerer Leistung und einer kleinen Emittanz mit einem einfachen HF-Koppler und geringen Kosten bei koaxialer Einkopplung und variabler externer Güte sowie geringer thermischer Belastung des supraleitenden Resonators zu erreichen.

  • Patent:
    Patentanmeldung DE 10 2004 055 256.8
Registration 03.12.2004 13:08, No. 6931
 
Verfahren zur Verbesserung der Strahleigenschaften einer supraleitenden Hochfrequenz-Fotoelektronenquelle
Janssen, D.
Abstract: Mit der Erfindung soll die Effektivität der supraleitenden HF-Fotoelektrode und die Strahleigenschaft, insbesondere die transversale Emittanz, für mittlere und hohe Leistungen verbessert werden.

  • Patent:
    DE 10 2004 005 612 A1
Registration 03.12.2004 10:02, No. 6897
 
High brightness electron guns for next-generation light sources and accelerators
Bluem, H. P.; Todd, A. M. M.; Cole, M. D.; Rathke, J.; Schultheiss, T.; Lewellen, J. (Consultant); Phillips, L. (Consultant); Preble, J. (Consultant); Ben-Zvi, I.; Srinivasan-Rao, T.; Neil, G. R.; Colestock, P.; Nguyen, D. C.; Wood, R. L.; Young, L. (Consultant); Janssen, D.
Abstract: Next-generation light sources and accelerators are being proposed that set unique requirements for the electron source parameters. No single source is suitable for the diverse applications, which have operating characteristics ranging from high-average-current, quasi-CW, to high-peak-current, single-pulse electron beams. Advanced Energy Systems, in collaboration with our various partners, is developing a variety of electron gun concepts for these important applications.

  • Contribution to Proceeding:
    9th European Particle Accelerator Conference EPAC 2004, 05.-09.07.2004, Lucerne, Switzerland
    Contributions to the Proceedings, 9th European Particle Accelerator Conference EPAC 2004, 92-9083-232-0, 899-901
  • Contribution to WWW:
    EPAC 2004 Contributions to the Proceedings, 9th European Particle Accelerator Conference EPAC 2004, 899-901, MOPLT156, 05.07. – 09.07.2004, Lucerne, Switzerland ISBN 92-9083-231-2 (Web version), ISBN 92-9083-232-0 (CD-ROM): http://epaper.kek.jp/e04/PAPERS/MOPLT156.PDF
Registration 09.11.2004 10:31, No. 6804
 
The influence of the main coupler field on the traverse emittance of a superconducting RF gun
Janssen, D.; Dohlus, M.
Abstract: The field disturbance in the RF coupler plane increases the transverse emittance of RF electron guns. This effect has been calculated for the Rossendorf superconducting RF gun. For 10 kW beam power the increasing is smaller than 5 %.

  • Contribution to Proceeding:
    9th European Particle Accelerator Conference EPAC 2004, 05.-09.07.2004, Lucerne, Switzerland
    EPAC 2004 Contributions to the Proceedings, 9th European Particle Accelerator Conference EPAC 2004, 92-9083-232-0, 327-329
  • Contribution to WWW:
    EPAC 2004 Contributions to the Proceedings, 9th European Particle Accelerator Conference EPAC 2004, 327-329, MOPKF013, 05.07. – 09.07.2004, Lucerne, Switzerland, ISBN 92-9083-231-2 (Web version): http://epaper.kek.jp/e04/PAPERS/MOPKF013.PDF
  • Poster:
    9th European Particle Accelerator Conference EPAC 2004, 05.-09.07.2004, Lucerne, Switzerland
Registration 09.11.2004 09:54, No. 6802
 
Test Measurements of a new TESLA Cavity Beam Position Monitor at the ELBE Linac
Sargsyan, V.; Schreiber, H. J.; Evtushenko, P.; Schurig, R.
Abstract: A new type of a cavity BPM proposed for beam position determination along the TESLA linac was tested at the accelerator ELBE in Rossendorf / Dresden. Measurements using an improved BPM (large and stable cross-talk isolation, signicantly less energy dissipation, a novel LO signal generation) were performed in single- and multi-bunch regimes. Agreement with expectations was found. The low bunch charge available allowed for preliminary measurements on sensitivity and position resolution, which extrapolated to TESLA would full the demands for precise bunch-to-bunch position determination. Possible improvements, in particular on the signal processing scheme, are also discussed.

  • Other report:
    2004 TESLA Reports, Papers from the TESLA collaboration September 2004
Registration 05.10.2004 10:27, No. 6685
 
Status of the 3 ½ Cell Rossendorf Superconducting RF
Janssen, D.; Büttig, H.; Evtushenko, P.; Lehnert, U.; Michel, P.; Schneider, Ch.; Stephan, J.; Teichert, J.; Volkov, V.; Kruchkov, S.; Myskin, O.
Abstract: The status of the Rossendorf superconducting RF gun is discussed. This gun allows continuous wave operation with an energy of 9.5 MeV and an average current of 1mA. The 3½ cell niobium cavity contains a normal conducting photocathode. A special choke flange filter at the cathode side prevent the RF leakage of the cavity. The design of the cavity, the tuner, the RF coupler the LHevessel together with the cryostat is finished and now in manufacturing. In the paper three features are discussed, which follows from the special demands of the 3½ cell superconducting RF gun. The first feature is the tuning system. For the cavity two different tuners are necessary, one for the half cell (gun cell) and one for the accelerating cells. The second feature is the tuning of the cathode. The beam properties depend very sensitive on the athode position. Therefore a special cathode tuner has been developed, which allows to move and to adjust the cathode position inside the cavity. The third no conventional feature is the excitation of a second RF mode inside the cavity. This is a magnetic mode (TE mode) which replaces the static magnetic field in normal conducting RF guns and decreases the transverse emittance of the beam by more than a factor of two.

  • Lecture (Conference):
    26th International Free Electron Laser Conference and 11th FEL Users Workshop, 29.08. - 03.09.2004, Trieste, Italy
  • Contribution to Proceeding:
    Proceedings of the 26th International Free Electron Laser Conference and 11th FEL Users Workshop, 359-362, THBOC05, 29.08.-03.09. 2004, Stazione Marittima, Trieste, Italy, 2005, ISBN: 88-87-992-02-9,
Downloads:
Volltext Proceedings 58,6 MB Remote resource

Registration 28.09.2004 11:47, No. 6665
 
An Electromagnetic Undulator for the Far Infrared at ELBE
Dekorsy, T.; Fahmy, K.; Grosse, E.; Michel, P.; Seidel, W.; Wolf, A.; Wünsch, R.
Abstract: The parameters of an envisaged undulator at the radiation source ELBE for the production of IR radiation up to 150 microns are presented.

  • Poster:
    Poster, 26th Int. Free-Electron Laser Conf. and 11th FEL Users Workshop, Trieste, Sep. 2004
  • Contribution to external collection:
    Proceedings of the 26th International Free-Electron Laser Conference and 11th FEL Users Workshop 389-391, September 2004, Trieste, Ital
Registration 26.08.2004 08:58, No. 6563
 
Overview of the present status of the SRF gun design and construction
Teichert, J.; Evtushenko, P.; Janssen, D.; Lehmann, W.-D.; Lehnert, U.; Michel, P.; Schneider, C.; Stephan, J.; Volkov, V.; Will, I.
Abstract: A status report on the SRF photo-injector activities at FZR within the CARE/PHIN project will be given. The new SRF gun has been designed for CW operation at the ELBE linac with an average current of 1 mA, 77 pC bunch charge, and 10 MeV energy. The basic concept of the gun, operating a normal conducting, thermally insolated photo-cathode within a superconducting cavity, have been taken from the first SRF half-cell gun [1] which was successfully tested. In this report the design layout of the SRF photo-injector, the parameters of the superconducting cavity and the expected electron beam parameters are presented. The SRF gun will have a 31/2-cell niobium cavity working at 1.3 MHz and will be operated at 2 K. The cavity consists of three full cells with TESLA-like shapes and a half-cell in which the photocathode is situated.
Keywords: SRF photo-injector, electron source, superconductivity, niobium cavity, electron acceleration

  • Lecture (Conference):
    1st Workshop of ELAN, 04.-06.05. 2004, Frascati, Rom, Italy
  • Contribution to Proceeding:
    1st Workshop of ELAN, 04.-06.05.2004, Frascati, Italy CARE-Note-2004-010-ELAN
Registration 16.06.2004 12:04, No. 6333
 
Machbarkeitstudie für einen industriellen supraleitenden Table Top Elektronenbeschleuniger
Schneider, C.; Büttig, H.; Enghardt, W.; Gabriel, F.; Janssen, D.; Michel, P.; Pobell, F.; Prade, H.; Kudryavtsev, A.; Haberstroh, C.; Sandner, W.; Will, I.
Abstract: At the Forschungszentrum Rossendorf the build-up of the superconducting 1.3 GHz accelerator ELBE is still in progress. Furthermore a new sc photo injector (SRF gun) is under development, which should accelerate electrons up to 10 MeV at 1.3 GHz frequency. The use of electron accelerators is also more and more interesting for applications where the destructive potential of the electrons are used like sterilization of medical waste and medical products, food irradiation or decontamination of sewage. For these processes a high power is required to achieve a high product throughput in a plant. The aim is therefore to use beam powers of around 100 kW or more. Since the applications of electron accelerators in industrial environments are steadily increasing one can speculate about transferring the above named state of the arte technology to industrial electron accelerators. At the FZR a feasibility study of such a table top electron accelerator (TTE) has been performed to investigate its technical limits and marketabilitys.
Keywords: Industrieller Beschleuniger; Fotoemissionskatode; Laser induzierte Emission; Präparationskammer zur Katodenbedampfung; Fotokatode in Beschleunigungskavität; supraleitender Resonator; superconducting cavity; Strahlleistung 50 kW; Strahlenergie 10 MeV; Kryostat; Sterilisation; Entkeimung; Lebensmittelbestrahlung; Lebensmittelpasteurisierung; Beseitigung organischer Schadstoffe; Kunststoffvernetzung

  • Wissenschaftlich-Technische Berichte FZR-410 2004
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Registration 01.06.2004 11:04, No. 6299
 
Emittance Compensation of a Superconducting RF Photoelectron Gun by a Magnetic RF Field
Janssen, D.; Volkov, V.
Abstract: For compensation of transverse emittance in normal conducting RF photoelectron guns a static magnetic field is applied. In superconducting RF guns the application of a static magnetic field is impossible. Therefore we put instead of a static field a magnetic RF field (TE-mode) together with the corresponding accelerating mode into the superconducting cavity of the RF gun. For a 3-cell cavity of the superconducting gun with frequencies f = 1.3 GHz for the accelerating mode and f = 3.9 GHz for the magnetic mode an a bunch charge of 1 nC a transversal emittance of 0.5 mm mrad has been obtained. In this case the maximal field strength on the axis were Ez = 50 MV/m for the accelerating mode and Bz = 0.34 T for the magnetic mode (this corresponds to Bs(max) = 0.22 T on the surface of the cavity). Possibilities for the technical realization (input of RF power for the TE mode, tuning of two frequencies in one cavity, phase stability) are discussed.

  • Physical Review Special Topics - Accelerators and Beams 7(2004)9, 090702
Registration 11.03.2004 11:00, No. 6128
 
A Superconducting Photo-Injector with 31/2-Cell Cavity for the ELBE Linac
Teichert, J.; Büttig, H.; Evthushenko, P.; Janssen, D.; Lehnert, U.; Michel, P.; Schneider, C.; Stephan, J.; Volkov, V.; Will, I.; Möller, K.; Lehmann, W.-D.
Abstract: After sucessful tests of an SRF gun with a superconducting half-cell cavity (*), a new SRF photo-injector for CW operation at the ELBE linac has been designed. In this report the design layout of the SRF photo-injector, the parameters of the superconducting cavity and the expected electron beam parameters are presented. The SRF gun has a 3 1/2-cell niobium cavity working at 1.3 MHz and will be operated at 2 K. The three full cells have TESLA-like shapes. In the half cell the photocathode is situated which will be cooled by liquid nitrogen.

  • Poster:
    J. Teichert et al., EPAC 2004 Contributions to the Proceedings, 9th European Particle Accelerator Conference EPAC 2004, 333-335, 05.07. – 09.07.2004, Lucerne, Switzerland
  • Contribution to Proceeding:
    9th European Particle Accelerator Conference, EPAC 2004, 05.-09.07.2004, Lucerne, Switzerland
    ISBN 92-9083-231-2 (Web version), ISBN 92-9083-323-0 (CD-ROM), 333-335
  • Contribution to WWW:
    EPAC 2004 Contributions to the Proceedings, 9th European Particle Accelerator Conference EPAC 2004, 333-335, MOPKF015, 05.07. – 09.07.2004, Lucerne, Switzerland, ISBN 92-9083-231-2 (Web version): http://epaper.kek.jp/e04/PAPERS/MOPKF015.PDF
Registration 11.03.2004 10:39, No. 6127
 
Electron beam diagnostic and the undulator field adjustment of the ELBE IR-FEL
Evtushenko, P.; Gippner, P.; Grosse, E.; Michel, P.; Seidel, W.; Wohlfahrt, D.; Wolf, A.; Wolf, U.; Wünsch, R.; Wustmann, B.; van der Geer, C. A. J.
Abstract: For the electron beam diagnostic in the undulator of the ELBE FEL two systems are completed. The first one consists of insertable OTR (Optical Transition Radiation)view screens. The same view screens will be used for the FEL optical resonator alignment. This is why there are very strong requirements on the long-term positioning reproducibility of the view screens. The second system is based on a single moveable YAG (Yttrium Aluminum Garnet activated by Cerium) screen, which can travel within the undulator vacuum chamber such that the electron beam position can be measured at any place in the undulator. Both systems are completed and successfully tested. Results of the tests as well as design ideas are presented. After transporting two undulator units to Rossendorf and installing the stainless steel vacuum chamber the magnetic field has been measured again and adjusted applying the pulsed-wire method. Irregularities of the undulator magnetic field could affect gain and wavelength of the FEL. Such effects were analyzed using numerical simulations.

  • Poster:
    25th International Free Electron Laser Conference, and the 10th FEL Users Workshop 2003, 08.-12.09.2003, Tsukuba, Ibaraki, Japan
  • Contribution to Proceeding:
    25th International Free Electron Laser Conference, and the 10th FEL Users Workshop, Part II, 08.-12.09.2003, Tsukuba, Ibaraki, Japan
    Extended Abstracts, book edition of the proceedings, 0-444-52727-8, II-29
Registration 01.12.2003 10:21, No. 5917
 
Beam loss detection at Radiation Source ELBE
Michel, P.; Teichert, J.; Schurig, R.
Abstract: The Rossendorf superconducting Electron Linac of high Brilliance and low Emittance (ELBE) delivers an 40 MeV, 1 mA cw-beam for different applications such as bremsstrahlung production, electron channeling, free-electron lasers or secondary particle beam generation. In this energy region in case of collisions of the electron beam with the pipe nearly all beam power will be deposited into the pipe material. Therefore a reliable beam loss monitoring is essential for machine protection at ELBE. Different systems basing on photo multipliers, compton diodes and long ionisazion chambers were studied. The pros and cons of the different systems will be discussed. Ionisazion chambers based on air-isolated RF cables installed some cm away parallel to the beam line turned out to be the optimal solution. The beam shut-off threshold was adjusted to 1 µC integral charge loss during a 100 ms time interval. Due to the favourable geometry the monitor sensitivity varies less than +/- 50 % along the beam line (different shielding conditions).

  • Lecture (Conference):
    6th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators, 05.05. – 07.05.2003, Mainz, Germany
  • Contribution to Proceeding:
    6th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators, 65 - 67, 05, 05.-07.05.2003, Main, Deutschland, 65-67
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Registration 26.11.2003 15:28, No. 5909
 
Superconducting RF guns for FELs
Janssen, D.; Büttig, H.; Evtushenko, P.; Lehnert, U.; Michel, P.; Möller, K.; Schneider, Ch.; Stephan, J.; Teichert, J.; Kruchkov, S.; Myskin, O.; Tribendis, A.; Volkov, V.; Sandner, W.; Will, I.; Quast, T.; Goldammer, K.; Marhauser, F.; Ylä-Oijala, P.
Abstract: The paper provides an overview of the advantages and problems of superconducting RF guns. The results of the Rossendorf experiments are presented here. These results are integrated in the design of a new 3.4 cell superconducting RF gun. The beam parameters of this gun correspond to the demands of the new generation of high current, high brightness injectors.
Keywords: Cavity; Superconductivity; Photocathode; Laser; Electron gun

  • Lecture (Conference):
    AES Meeting,13.01.2004, Medford, USA
  • Nuclear Instruments and Methods in Physics Research Section A, 528(2004)1-2, 305-311
    DOI: 10.1016/j.nima.2004.04.076
  • Contribution to Proceeding:
    25th International Free Electron Laser Conference, and the 10th FEL Users Workshop, 08.-12.09.2003, Tsukuba, Ibaraki, Japan
    41.60.Cr; 41.75.Fr; 42.55.Xi; 82.25.-j
Registration 25.09.2003 10:50, No. 5820
 
Review of the Status of SRF Photo-Injectors
Teichert, J.; Büttig, H.; Evtushenko, P.; Janssen, D.; Lehnert, U.; Michel, P.; Schneider, C.
Abstract: Superconducting radio frequency photoelectron injectors open the way to low-emittance electron beams in continuous-wave operation mode. Their progress is essential for future projects of high-power free electron lasers, energy recovery linacs and next generation light sources. In this presentation, the technical issues associated with the design, construction and operation of SRF photo-injectors will be reviewed together with the progress in several laboratories during the past few years. Results of the operation of the Rossendorf SRF photo-injector with an 1.3 GHz niobium half cell and the future projects are discussed in detail.
Keywords: photoelectron-injector electron source superconductivity superconducting cavity rf-photogun srf-photo-injector

  • Lecture (Conference):
    11th Workshop on RF-Sperconductivity SRF 2003, 5 pages, 08. – 12. September 2003, Lübeck/Travemünde, Germany
  • Contribution to Proceeding:
    11th Workshop on RF-Sperconductivity SRF 2003, 5 pages, 08. – 12. September 2003, Lübeck/Travemünde, Germany
Registration 19.09.2003 15:19, No. 5779
 
Status of the ELBE accelerator - a driver for different radiation sources
Michel, P.; Gabriel, F.; Grosse, E.
Abstract: At the Forschungszentrum Rossendorf (FZR) the new facility ELBE for research with various kinds of radiation (IR from FEL´s, quasi-monochomatic channeling X-rays, bremsstrahlung in the MeV range, neutrons) is presently under construction. ELBE is centered around a superconducting Electron Linac which will produce quasi-continuous beams of high Brilliance and low Emittance. Electron beams with variable bunch charges up to 80 pC and variable repetition rates up to 260 MHz are produced in a pulsed thermionic DC gun followed by a two-stage RF bunching system. Two cryomodules each containing two 9-cell RF-cavities (1.3 Gz) accelerate the electrons t 40 MeV. At present the 250 keV injector has been installed and tested. The accelerator is planned to deliver a 20 MeV beam at the end of 2000. First results of beam parameter measurements at the 250 keV injector will be shown. Detailed transverse emittance studies by multi-slit techniques and investigations concerning the longitudinal phase space will be discussed

  • Lecture (Conference):
    FEL-Conferenz 2000
Registration 02.09.2003 10:15, No. 5752
 
Comissioning of the ELBE Superconducting Electron Linac
Michel, P.; Büchner, A.; Evtushenko, P.; Gabriel, F.; Lehnert, U.; Teichert, J.; Voigtländer, J.
Abstract: The radiation source ELBE at Forschungszentrum Rossendorf is based on a superconducting linear accelerator that produces a cw electron beam up to 40 MeV and 1 mA. In 2001 first stage of the ELBE-linac was put into operation. The main electron beam parameters like energy, energy spread, transverse emittance and bunch length were specified and several online diagnostic tools for ELBE routine high-power operation were tested, such as λ/4-stripline monitors and beam-loss detectors.

  • Lecture (Conference):
    EPAC 2002, Paris, Frankreich, 03.06. - 07.06.2002
  • Contribution to external collection:
    EPAC 2002, Paris, Frankreich, 03.06. - 07.06.2002
Registration 01.09.2003 11:26, No. 5738
 
Application of autocathode in a superconducting electron RF injector for the industry acclerator
Janssen, D.; Volkov, V. N.; Konstantinov, S. G.; Kudryavtsev, A. M.; Myskin, O. K.; Petrov, V. M.; Tribendis, A. G.
Abstract: Recently, publications on the development of cold field emission cathodes with current high density at rather low voltage applied are very broadly spread [1,2]. In the work presented here, the computer simulation has been performed for one of the versions of application of such cathodes in a superconducting RF cavity of the electron injector designed for the industrial accelerator.

  • Lecture (Conference):
    APAC01, September 17-21, 2001, Beijing, China
Registration 28.08.2003 08:07, No. 5697
 
The optical resonator of the IR-FEL at ELBE
Seidel, W.; Evtushenko, P.; Gippner, P.; Grosse, E.; Jainsch, R.; Oepts, D.; Sobiella, M.; Wohlfarth, D.; Wolf, A.; Wolf, U.; Wünsch, R.; Wustmann, B.
Abstract: To allow first lasing at the ELBE FEL at the end of 2003 various efforts have been made. In particular, the optical resonator including the system which controls and stabilizes its length and alignment has been installed and tested. The resonator length is controlled by means of an interferometer beam passing diagonally from one side of the upstream mirror to a retroreflector on the opposite side of the downstream mirror.
To avoid temperature effects the mirror holders have been equiped with a special heating and cooling system which stabilizes the mirror temperature. Simulating maximum laser power the cavity detuning due to temperature changes has not exceeded 1micron.
The alignment of the resonator axis is controlled by the overlap of two He-Ne laser beams entering the resonator from each side. To predict the outcoupled laser power and the upper wavelength limit we have modeled the IR-beam propagation in the optical resonator. In particular, the vacuum chamber in the undulator, which is 10 mm high, and the outcoupling hole affect the beam power and profile significantly; respective results will be presented.
Keywords: Keine

  • Poster:
    25th Int. Conf. on Free Electron Laser, Tsukuba, Ibaraki, Japan, 8 - 12 September 2003
  • Nuclear Instruments and Methods in Physics Research A 528(2004)1-2, 199-202
Registration 27.08.2003 16:11, No. 5695
 
Generation of sub-picosecond electron bunches from superconducting 5.3 cell RF gun and coherent wiggler radiation
Volkov, V. N.; Janssen, D.; Wünsch, R.
Abstract: In this paper we discuss the possibility to gernerate subpicosecond electron bunches with a small emittance directly from the superconducting 5.3 cell rf gun by illuminating a photo-cathode in the rf cavity with a phaselocked 3 ps laser pulses. The bunch length compression caused by the RF force take place in the first TESLA cell of the rf gun. Numerical simulations of the beam dynamics in the rf gun and of the radiation of the corresponding electron bunch in a wiggler predict a coherent enhancement of radiaton for wavelength smaller than 100 micron.

  • Lecture (Conference):
    PAC 2001, June 18-22, 2001 Chicago, Illinois, USA
  • Contribution to external collection:
    PAC 2001, June 18-22, 2001 Chicago, Illinois, USA
Registration 25.08.2003 07:47, No. 5678
 
First operation of a superconducting RF-Gun
Janssen, D.; Büttig, H.; Evtushenko, P.; Freitag, M.; Lehnert, U.; Hartmann, B.; Michel, P.; Reppe, B.; Schamlott, A.; Schneider, C.; Schurig, R.; Teichert, J.; Gabriel, F.; Möller, K.; Quast, T.; Konstantinov, S.; Kruchkov, S.; Kudryavtsev, A.; Myskin, O.; Petrov, V.; Tribendis, A.; Volkov, V.; Sandner, W.; Will, I.; Matheisen, A.; Moeller, W.; Pekeler, M.; Stein, P. von; Haberstroh, Ch.
Abstract: For the first time, a superconducting RF gun where a photo cathode is inside a superconducting cavity has been working stably over a periode of seven weeks. The gun with a half cell cavity has been operated in the cryostat at 4.2K. A maximal field strength of 22MV/m in the cavity and maximal beam energy of 900keV have been obtained. Measurements of beam current, transmission, energy spread and transverse emittance are presented.

  • Nuclear Instruments and Methods in Physics Research A 507(2003)1-2, 314-317
Registration 22.08.2003 10:19, No. 5677
 
A New Beam Loss Measurement System For ELBE
Schurig, R.; Evtushenko, P.; Lehnert, U.; Michel, P.; Teichert, J.
Abstract: During the commissioning of the first accelerator stage of ELBE, beam loss was measured with photomultipliers and self-testing integrating electronics. While the electronics worked flawless, the correct positioning of the monitors and finding a good trade off between sensitivity and saturation of the photomultipliers were a problem. A new BLM system, consisting of ionization chambers, acquisition electronics and monitoring software is now under construction. Coaxial cable with air dielectricum, normally used in high power applications, makes the ionization chamber and will be installed along the beamline. The outer conducter of the cable is subsectioned, the inner conductor not. The current on the inner conductor represents the total beam loss. The current from each outer conductor segment to ground is measured separately, providing position resolution of the beam loss. On each section, a RISC microcontroller (Slave) with built in ADC is used for data acquisition and continuous average calculation. One microcontroller (Master) handles the communication with the slaves via RS-485 bus and acts as an interface to a PC running monitoring software. First test have been done successfully.

  • Poster:
    Beam Instrumentation Workshop 2002,Brookhaven National Laboratore, Poster Session
Registration 21.08.2003 13:39, No. 5675
 
A Beam Loss Measurement System with Longitudinal Resolution
Schurig, R.; Michel, P.
Abstract: At ELBE, beamloss is measured in two different ways. Long ionization chambers (LIC) made from coaxial cable and having an air dielectric are used to detect beam loss at critical sites of the machine. In the second system, beam current is measured at three different locations. The sum signals from two stripline beam position monitors and the nuclear physics beam dump current are compared. A difference in current at these points indicates that portions of the electron beam are lost somewhere. Above a certain level the interlock is triggered and the beam is switched off. Both kinds of measurement are described in detail elsewhere in this annual report.

  • Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-375 April 2003
Registration 21.08.2003 13:24, No. 5674
 
A Resonant Beam Current Monitor for ELBE
Schurig, R.; Büttig, H.; Büchner, A.
Abstract: During the first stages of commissioning ELBE, the beam current could be measured directly at the gun, the macropulser aperture and at the beam dump. Later, a package consisting of a resonant beam current monitor (RBCM) and a resonant beam position monitor was added. The result of the RBCM test are described in this paper.

  • Contribution to FZD-Jahresbericht:
    Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-341 April 2002, 15-15
Registration 21.08.2003 13:17, No. 5673
 
RF System and Measurements at the Superconducting RF Gun
Büttig, H.; Schurig, R.; Tribendis, A.
Abstract: The paper gives an overview on the RF-system developed for the Superconducting Photo RF Gun at FZ-Rossendorf and a brief discussion an RF-measurements at the superconducting gun-cavity.

  • Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-375 April 2002, 49
Registration 11.08.2003 10:29, No. 5666
 
The ELBE- RF-Coupler
Büttig, H.
Abstract: The power-point presentation gives an overview on RF-coupler development, operational experience at the ELBE-Linac and the coupler test-equipment used at FZ-Rossendorf.

  • Lecture (Conference):
    Proc. of Workshop an 1.3 GHz couplers for cw operation at power levels between 10 and 100 kW ACCEL Instr. GmbH 09.04.2002
Registration 11.08.2003 10:19, No. 5665
 
Optimizing the Antenna Tip-Length of the ELBE Main RF Coupler
Büttig, H.
Abstract: The ELBE LINAC is equipped with superconducting TESLA 9-cell cavity resonators. Its RF-coax coupler antennas are designed to operate each cavity withe 8...10 kW beam power. The paper describes a procedure on optimising the antenna- length of the RF-coupler at room temprature.

  • Contribution to FZD-Jahresbericht:
    Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-341 April 2002, 8-9
Registration 11.08.2003 10:08, No. 5664
 
The Radiation Source ELBE at the Research Center Rossendorf
Lehnert, U.; Büchner, A.; Büttig, H.; Enghardt, W.; Evtushenko, P.; Gabriel, F.; Gippner, P.; Grosse, E.; Guratzsch, H.; Michel, P.; Naumann, B.; Neubert, W.; Prade, H.; Schamlott, A.; Schilling, K. D.; Schwengner, R.; Seidel, W.; Teichert, J.; Voigtländer, J.; Wagner, A.; Wagner, W.; Wolf, A.; Wolf, U.; Wünsch, R.
Abstract: At the Forschungszentrum Rossendorf (FZR) the new facility ELBE for research with various kinds of radiation is presently under construction. ELBE is centered around a superconductiong Electron Linac which will produce quasi-continuous beams of high Brillance and low Emittance. Preliminary results of the first stage accelerator tests will be shown. The 40 MeV / 1 mA electron beam will be used to drive free-electron lasers for the production of infrared light in the 5-510µm wavelength range. X-ray beams in the 5-50 keV energy range will be generated using channeling radiation. Additionally, the ELBE facility will provide bremsstrahlung and photoneutron beams for investigations in nuclear physics and technology.

  • Contribution to external collection:
    Electron-Photon Interaction in Dense Mediaed. H. Wiedemann NATO Science Series II Vol. (2002) 49 p. 313
Registration 20.06.2003 08:18, No. 5612
 
First Operation of the ELBE Linear Accelerator
Lehnert, U.; Evtushenko, P.; Michel, P.; Teichert, J.
Abstract: The new radiation source "Strahlungsquelle ELBE" at the Forschungszentrum Rossendorf (FZR) will us the high brilliance electron beam from a linac with superconducting rf-cavities to porduce various secondary beams for experiments in nuclear science, solid state physics, materials research, environmental chemisty and in the life sciences. During the year 2001 all components belonging to the first stage of ELBE (20 MeV) were successfully put into operation. The main beam properties were measured and it was shown that all major design parameters could be reached with the ELBE accelerator. In the low bunch charge mode of operation intended for radiation physics applications a transversal emittance of 3 mm mrad was measured. At the 77 pC maximum bunch charge the emittance is still better than 10 mm mrad, well sufficient for driving the ELBE free-electron lasers. The longitudinal phase space properties are mainly determined by the capture process of the electron bunches into the first accelerator cavity and could, thus, be characterized by measuring the energy spectrum of the beam while scanning the rf-phase of the second cavity. These measurements at 3 pC bunch charge vielded an emittance of 57 keV ps and a bunchlength of 2 ps, in good agreement with theoretical predictions and with bunch length measurements using an autocorrelation technique.

  • Poster:
    The XXI International Linac ConferenceGyeongju, Korea Auguest 19 - 23, 2002
Registration 20.06.2003 07:19, No. 5611
 
Design, Construction and Test of Stripline BPM Electronics
Schurig, R.; Evtushenko, P.; Gabriel, F.; Büttig, H.
Abstract: Commisioning and operating the ELBE accelerator requires exact knowledge and easy, reproduceable control of various parameters. Important parameters like beam position and beam current are measured with a system consisting of a stripline BPM (beam position monitor), conversion electronics, data acquisition and monitoring software. The design of the electronics is described in this paper

  • Contribution to FZD-Jahresbericht:
    Wissenschaftlich-Technische Berichte / Forschungszentrum Rossendorf; FZR-341 April 2002, 14-14
Registration 13.06.2003 10:39, No. 5599
 
Stripline beam position monitors for ELBE
Evtushenko, P.; Büttig, H.; Büchner, A.; Jordan, K.; Michel, P.; Schurig, R.
Abstract: The ELBE accelerator needs a non-destructive system for measurement of the electron beam position at about 30 location. To obtain the required resolution about 100mm a system of stripline beam position monitors (BPM) is under design. The stripline BPM can work in full power mode almost without influence on the beam. To study the basic operational principle of the stripline BPM and to get information about BPM signal behavior we did a set of measurements on the ELBE injector. The resolution of the BPM was measured as a function of the electron beam current; at an electron beam current of 1mA the resolution is about 30mm. One of the BPMs will be installed upstream the cryomodule. Since the power spectrum of the beam depends on the bunch length, measurements in the frequency domain give us information about the length of the bunch entering the cryomodule with RF cavities. The BPM will serve for setting correct phase and power of both bunchers of the injector and for measurements of the electron beam position at the entrance of the cryomodule. There are two alternative schemes of the BPM electronics under development. The first one is based on the logarithmic amplifier AD8313, another one on the an rms-responding true power detector AD8361. Both of them can process RF signals with frequencies up to 2.5GHz. The BPM electronics will operate at the fundamental frequency of the accelerator which is 1.3GHz.


1 FZR, , Germany
2 TJNAF, Newport News, Virginia, USA

  • Lecture (Conference):
    Talk at DPG 2001 Erlangen
Registration 13.06.2003 10:08, No. 5598
 
Performance of the ELBE BPM Electronics
Evtushenko, P.; Schurig, R.
Abstract: The radiation source ELBE is based on a superconducting LINAC. Initially it was designed to operate in CW mode with repetition rates either 13 MHz either 260 MHz. Later it was decided to operate the accelerator with reduced repetition rates for diagnostic reasons and for certain users. Now it is possible to operate with bunch frequency 13/n MHz, where n can be 2,4,8,16,32,64 and 128. It is required that the BPM system supports any of these operation modes. A core element of the BPM electronics is a logarithmic detector AD8313 made by Analog Devices Inc. The logarithmic detector is a direct RF to DC converter rated up to 2.5 GHz. Initial design of the BPM electronic was sophisticated only for CW operation with repetition rate more than 10 MHz, since bandwidth of the AD8313 is about of 10 MHz. Additionally a sample and hold amplifier is built in to provide enough time for an ADC to make measurements. The sample and hold amplifier is synchronized with a bunch frequency. In the paper we present results of the modified BPM electronics test.

  • Poster:
    6th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators, 202 – 204, 05.05. – 07.05.2003, Mainz, Germany
  • Contribution to Proceeding:
    6th European Workshop on Beam Diagnostics and Instrumentation for Particle Accelerators, 05.-07.05.2003, Mainz, Germany
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Registration 13.06.2003 07:56, No. 5597
Pages: [All] [1] [2]
Druck-Version Homepage Forschungszentrum Dresden-Rossendorf
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