Neutron measurements with ultra-thin 3D silicon sensors in a radiotherapy treatment room using a Siemens PRIMUS linac

• Published in: Physics in medicine & biology Vol. 58; no. 10; p. 3227
• Main Authors: Guardiola, C, Gómez, F, Fleta, C, Rodríguez, J, Quirion, D, Pellegrini, G, Lousa, A, Martínez-de-Olcoz, L, Pombar, M, Lozano, M
• Format: Journal Article
• Language: English
• Published: England 21-05-2013
• Subjects: Boron - chemistry; Gamma Rays; Isotopes; Monte Carlo Method; Neutrons - therapeutic use; Radiometry; Radiotherapy, Computer-Assisted - instrumentation; Radiotherapy, Computer-Assisted - methods; Silicon - chemistry
• ISSN: 1361-6560
• DOI: 10.1088/0031-9155/58/10/3227

The accurate detection and dosimetry of neutrons in mixed and pulsed radiation fields is a demanding instrumental issue with great interest both for the industrial and medical communities. In recent studies of neutron contamination around medical linacs, there is a growing concern about the secondary cancer risk for radiotherapy patients undergoing treatment in photon modalities at energies greater than 6 MV. In this work we present a promising alternative to standard detectors with an active method to measure neutrons around a medical linac using a novel ultra-thin silicon detector with 3D electrodes adapted for neutron detection. The active volume of this planar device is only 10 µm thick, allowing a high gamma rejection, which is necessary to discriminate the neutron signal in the radiotherapy peripheral radiation field with a high gamma background. Different tests have been performed in a clinical facility using a Siemens PRIMUS linac at 6 and 15 MV. The results show a good thermal neutron detection efficiency around 2% and a high gamma rejection factor.