Mapping thermal neutron fluence in a LINAC radiotherapy room using novel ultrathin PIN diodes using an enriched boron-10 converter layer

F. ZAMORANO; M. PEREZ; C. FLETA; J. BLOSTEIN; J. MARTIN; J. IRAZOQUI; S. BIANCHINI; F. ALCALDE BESSIA; M. SOFO HARO; M. GOMEZ; J. LIPOVETZKY

Conferencia; 2022 International Conference on Neutron Scattering; 2022

We present the results of thermal neutron detection in a radiotherapy facilitywith a LINAC operated above the photonuclear threshold using the novelU3DTHIN lateral PIN photodiodes developed by the CMN (Barcelona, Spain).The thermal neutron flux was measured in several positions in a LINAC basedradiotherapy irradiation room and its surroundings, evaluating the effect of theinternal door designed for neutron shielding. The LINAC was used in the 15MeV configuration, with irradiations of 100 Monitor Units. The sensor detecteda comparable number of neutrons in different positions inside the irradiationroom, with a reduction of 100 times at the outer side of the access corridor,and a reduction of ≈400 times outside the external door or in the control room.The initial calibration procedure is also described.