PROBLEM TO BE SOLVED: To provide a neutron sensitivity measuring method capable of accurately measuring neutron sensitivity of a neutron detector without irradiating neutron. SOLUTION: In the neutron sensitivity measuring method of a neutron detector, a fissile material containing mother species is coated at least one side and an anode and a cathode filled with an ionization gas in between are provided. By impressing a voltage of specific potential difference between the anode and the cathode in a state without irradiating the neutron detector by neutron, an α-ray current (Iα) flowing between the anode and the cathode due to the ionization of the ionization gas by the α-ray emitted from the fissile material is measured. Referring to a measuring range where the impressed voltage and the α-ray current (Iα) are practically proportional within at least 50 volts, the α-ray current value (Iα0) extrapolated at 0 V of the impressed voltage between the anode and the cathode is obtained by extrapolation using the proportionality relation.
NEURON SENSITIVITY MEASURING METHOD FOR NEUTRON DETECTOR