Leipzig 2002 – scientific programme

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ST: Strahlenphysik und Strahlenwirkung

ST 5: Strahlentherapie mit schnellen Ionen

ST 5.2: Fachvortrag

Tuesday, March 19, 2002, 14:45–15:15, HS 14

Low energy electron emission pattern induced by swift ions in solids and its interest in ion radiotherapy treatment planning — •Serge Dreuil¹, Siegbert Hagmann^1,2, Hermann Rothard³, and Gerhard Kraft¹ — ¹Gesellschaft für Schwerionenforschung, Darmstadt — ²Institut für Kernphysik, Universität Frankfurt — ³Centre Interdisciplinaire de Recherche Ions Lasers, Caen, France

One of the critical issues in ion radiotherapy is the accuracy of the treatment planning program in terms of effective biological damage. At the GSI Heavy Ion Radiotherapy facility, the calculation of the Relative Biological Efficiency (RBE) is based on a track structure model which relies on secondary electron emission spectra as key input parameter. However, due to lack of data in condensed matter for the most relevant electron energy range with respect to damage of biological structures (threshold to 500 eV), electron spectra are scaled from experiments using gaseous targets.

First measurements on solid targets did show some deviation from the gas measurements [1]. We will continue these measurements of the ion doubly differential electron emission cross section (i.e. both energy and polar angle of emission) in thin solid foils and in a systematic way. A previously developed electrostatic toroidal spectrometer will be used and a variety of light to heavy projectiles with beam energies ranging from 0.1 to few 100 MeV/u will be studied.

[1] T.Zäpfel et al., Nucl. Instr. and Meth. B (2002), in press.