RADIOCHEMICAL DETECTOR OF FAST NEUTRON FLUX DENSITY Russian patent published in 2017 - IPC G01T3/00 

FIELD: physics.

SUBSTANCE: radiochemical detector of fast neutron flux density comprises a vial with a powdered active substance placed in the flux of fast neutrons, a gas system filled with the carrier gas, and a flow meter connected to the recording and information processing system. The gas system comprises a reservoir with a carrier gas, valves, and a gas flow controlling system. The vial with an active substance is connected to the gas system, wherein the vial input is connected to the reservoir with the carrier gas, and the output - to the input of the flow meter. Microcrystalline powder of dehydrated oxalate (oxalate H₂C₂O₄⋅2H₂O) of an alkali metal or alkaline earth metal is used as an active substance, as a result of nuclear reactions of neutrons, with the nuclei of which the radioactive inert gas - radioactive isotopes of helium, neon, argon, krypton or xenon, is formed. Herewith the vial is formed as a column filled with a powdered active substance broken into equal domains of length H, divided by equal intervals of length h, in which the porous inserts with the same length h of inert material are located, wherein the domain length H is selected from the condition

,

where S - the cross-section column area; N - the number of the active substance atoms per unit volume; - σ the cross-section of the nuclear neutron reaction with nuclei of alkali or alkaline earth metal Me of the active substance; Fn - the neutron flux density; l - the column length; k - the number of domains in the column, and the length h of the porous insert is selected from the condition

,

where L - the distance from the column to the flow meter; D - the diffusion coefficient of the radioactive gas in the carrier gas; G - the carrier gas flow in the gas system.

EFFECT: empowering and improving the efficiency of the detector.

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