METHOD OF MEASURING FLUENCE OF SLOW NEUTRONS USING MONOCRYSTALLINE SILICON Russian patent published in 2013 - IPC G01T3/08 

FIELD: physics.

SUBSTANCE: method involves measuring resistivity of monocrystalline silicon before and after irradiation, irradiation with an unknown neutron fluence, annealing radiation defects in silicon after each irradiation, wherein the silicon is irradiated in a cadmium screen with thickness of 0.5-1.5 mm and without a cadmium screen; cadmium ratio is calculated based on changes in specific conductance R_cd = (σ - σ₀)/( σ_Cd - σ_0,cd), where σ_0,cd, σ₀ denote specific conductance before irradiation in the cadmium screen and without the cadmium screen, σ_cd, σ denote corresponding specific conductance of cadmium in the cadmium screen and without the cadmium screen after irradiation and annealing, and the absolute effective fluence of slow neutrons is determined, where e, µ_p denote charge and mobility of electrons in silicon monocrystals, χ_t denotes the self-screening coefficient of slow neutrons in a silicon disc, Σ_t denotes the macroscopic reaction cross-section of radiation capture of slow neutrons of silicon-30, F_Cd is a compensation factor which takes into account absorption of epithermal neutrons in cadmium.

EFFECT: change in absolute values of fluence of slow neutrons without additional calibration, independence of measurement results from the neutron spectrum.