Online neutron fluence measurement at university hospital essen neutron therapy facility using gallium arsenide LEDs (Conference Paper)

摘要

The detector and sensor group of the West German Proton Therapy Centre (WPE) has developed a novel real-time neutron fluence monitor based on tiny, inexpensive, commercially available GaAs-LEDs. The linear detection range for d(14)+Be neutrons was evaluated to be 5.0 × 10~8-2.0 × 10~(11) neutron.cm~(-2). However, this monitor can be used universally for neutrons of any energy distribution. Using scaling factors, fluence calibration curves for 1 MeV and 14 MeV D+T fusion neutrons have been calculated. The sensitivity of the detector increases with increasing neutron energy. This makes it suitable for the detection of high-energy neutrons, providing an extra advantage for use at a proton therapy facility where there is a high proportion of high-energy neutrons. The detector is practically not sensitive to photons. A prototype of the online GaAs-LED based neutron fluence monitor has been tested successfully at University Hospital Essen neutron therapy facility and will be implemented at WPE in the near future.