Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The dosimetric characterization of laser-accelerated electrons applied for the worldwide first systematic radiobiological in vitro cell irradiations will be presented. The laser-accelerated electron beam at the JeTi laser system has been optimized, monitored and controlled in terms of dose homogeneity, stability and absolute dose delivery. A combination of different dosimetric components were used to provide both an online beam as well as dose monitoring and a precise absolute dosimetry. In detail, the electron beam was controlled and monitored by means of an ionization chamber and an in-house produced Faraday Cup for a defined delivery of the prescribed dose. Moreover, the precise absolute dose delivered to each cell sample was determined by an radiochromic EBT film positioned in front of the cell sample. Furthermore, the energy spectrum of the laser-accelerated electron beam was determined. As presented in a previous work of the authors, also for laser-accelerated protons a precise dosimetric characterization was performed that enabled initial radiobiological cell irradiation experiments with laser- accelerated protons. Therefore, a precise dosimetric characterization, optimization and control of laseraccelerated and therefore ultra-short pulsed, intense particle beams for both electrons and protons is possible, allowing radiobiological experiments and meeting all necessary requirements like homogeneity, stability and precise dose delivery. In order to fulfil the much higher dosimetric requirements for clinical application, several improvements concerning, i.e., particle energy and spectral shaping as well as patient safety are necessary.