New method of detector protection of thermal neutrons on stationary atomic reactors

New way of creation of protection of detectors of thermal neutrons on the basis of boric and helium counters in conditions of stationary nuclear reactors is offered. The way is based on a principle transmission -absorption, when the protection does not contain absolutely of neutrons moderators, and consists from absorbers only (boron carbide or 10B). The absorbers attenuate a flow only of those neutrons, which are sensed by the detector, the other neutrons pass through protection and detector without change of energy. Thanking this thickness of protection is reduced up to several centimeters, weight - up to several kilograms. Such protection was used on the Belarus nuclear reactor for attenuating of a flow of background neutrons to both detectors of spectrometer and diffractometers, where one have shown high efficiency. 2 figs., 3 refs