出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The radiation field of heavy-ion beams used for radiotherapy applications is significantly affected by
nuclear fragmentation processes along the penetration path in tissue, causing an attenuation of the primary
ion beam flux and the build-up of light fragments including fast neutrons. The emission of secondary
fragments from 200 MeV/u carbon ions delivered from the synchrotron SIS-18 at GSI was investigated
using a water absorber as tissue-equivalent beam stopping target. Energy spectra, angular distributions
and yields of fast neutrons and charged particles emerging from the absorber downstream were
investigated by using fast scintillation detectors and time-of-flight techniques. From the resulting yield of
0.54 neutrons (En>10 MeV) per primary 12C ion a neutron dose of 5.4 mSv per Cobalt Gray Equivalent
(GyE) delivered to the target volume is estimated. Additional measurements employing a wide-energy
neutron detector (WENDI-II) under identical irradiation conditions were found to be in fair agreement
with the dose estimate based on the measured fast neutron fluences.
