Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The advent of high power laser systems providing pulse rates of a few pulses per minute in the field of laser ion acceleration has brought medical applications such as ion therapy of cancer closer into reach. Although the proton energies are still not high enough for patient treatment, they are sufficient to start first experiments on dosimetry and the biological effectiveness. In contrary to conventional accelerators, the laser ion acceleration delivers proton bunches with a very high charge in short times with a broad energy spectrum. Thus new concepts in dosimetry and irradiation are necessary.
It is evident, that applications with biological material have demanding requirements to the proton energy spectrum and its stability. In this paper we present a robust scheme to provide stable energy spectra for first cell irradiation experiments performed with the Dresden 150 TW laser system DRACO at a dose rate of about 1 Gy/min. A second paper will concentrate on the radiobiological aspects of the experiment and the complex dosimetry issues.
In addition to the production of a reproducible proton spectrum the scheme involves magnetic filtering. Based on a simple non-focusing magnetic dipole equipped with two apertures it makes use of an energy dependent angular asymmetry of the proton spectra and protons with energies above 7 MeV originating from a 2 μm thick Titanium foil are led to the cell sample.
S.D. Kraft, et al., Dose dependent biological damage of tumour cells by laser-accelerated proton beams, New Journal of Physics 12, 085003(2010)