Small Si-Li detectors for thermal neutron on-line measurements

Small semiconductor detectors with 6Li radiation sources are described. The detectors are supposed to be used in thermal neutron fluxes of up to 109 cm-2s-1. Their efficiency varies from 2.452x10-3 cm2 to 1.927x10-5 cm2. Results are given of measurements of thermal neutron distribution inside various phantoms irradiated with BNCT (Boron Neutron Capture Therapy) epithermal beams at the HFR reactor in Petten and the LVR-15 reactor in Rez. The maximum thermal fluence rate in a human head phantom was 9.64x106 cm-2s-1 MW-1 at the LVR-15 reactor and 5.96x108 cm-2s-1 at the HFR reactor. 3 tabs., 4 figs., 7 refs