RADIOCHEMICAL METHOD FOR MONITORING FAST NEUTRON FLUX Russian patent published in 2006 - IPC G01T3/00 

FIELD: nuclear physics; metering intensive neutron fluxes including those in nuclear and fusion reactor cores and neutron-generating targets.

SUBSTANCE: proposed radiochemical method involves irradiation of active material in the form of microcrystalline powder of dehydrated alkali metal oxalate by fast neutron flux. Radioactive gaseous products of nuclear reactions which are, essentially, inert gases are separated from active material and their disintegration is recorded. Used as alkali metal are lithium isotopes ⁶Li or ⁷Li, or their mixtures, sodium isotope ²³Na, potassium isotopes ³⁹K and ⁴¹K, or their mixtures, rubidium isotopes ⁸⁵Rb and ⁸⁷Rb, or their mixtures, or cesium isotope ¹³³Cs, as well as beryllium isotope ⁹Be, magnesium isotope ²⁶Mg, calcium isotopes ⁴⁰Ca, ⁴²Ca, ⁴⁴Ca,⁴⁶Ca, and ⁴⁸Ca, or their mixtures, strontium isotope ⁸⁸Sr, or barium isotope ¹³⁸Ba. Respective radioactive isotopes of helium, neon, argon, krypton, or xenon are used to produce inert gas. Gaseous radioactive products of nuclear reactions are separated from active material due to diffusion. Mean size of powdered microcrystals, their amount, and rate of transfer of separated radioactive inert gas to point of recording its decomposition are chosen bearing in mind that total mean time of radioactive inert gas escape from active material up to initial moment of recording radioactive material disintegration should be shorter than half-life period of radioactive inert gas.

EFFECT: facilitated procedure, enhanced efficiency, ability of selective real-time monitoring of different-energy neutrons.

1 cl, 4 dwg, 1 tbl