CALIBRATION METHOD OF NEUTRON COINCIDENCE METHOD PLUTONIUM DETERMINATION DEVICE

摘要

PROBLEM TO BE SOLVED: To calibrate simply a determination device without being restricted by an isotope composition ratio of plutonium, by using a neutron coincidence efficiency calculated theoretically by specific equations from a distribution of the number of spontaneous fission neutrons of a nuclide. ;SOLUTION: A neutron coincidence efficiency (ε) of a determination device is determined by equations I-III by using a whole neutron detection efficiency (f), a neutron attenuation time constant (γ), a coincidence gate time width Tm, a trigger after-waiting time width Tw, and a plural-neutron coincidence emission probability distribution (distribution of spontaneous fission neutrons) (ν distribution: P ν) of a measuring object nuclide, which are inherent in a device. In this case, the whole neutron detection efficiency (f) and the neutron attenuation time constant (γ) are determined by actual measurement or by theoretical calculation, and the coincidence gate time width Tm and the trigger after-waiting time width Tw are determined by design values of a measuring circuit or by actual measurement. By this calibration method, calibration (determination of the neutron coincidence efficiency (ε)) can be executed without using the measuring object nuclide as a calibration standard sample.;COPYRIGHT: (C)2000,JPO