IEC 62372:2021 pdf download-Nuclear instrumentation – Housed scintillators – Test methods of light output and intrinsic resolution.
For each value of energy, the position of a maximum of a peak of full absorption is defined. The values of the nonlinearity and the initial point of assembly conversion response shall be defined using a housed scintillator based on thallium-activated sodium iodide single crystal during irradiation by gamma-radiation. Pulse height spectra are measured using monoenergetic gamma radiation with at least five energy values in the range from 300 keV to 1 500 keV. For each energy value the total absorption peak maximum position should be defined. The light output of a housed scintillator may be used to determine the nonlinearity and the initial point of assembly conversion response in cases where it is necessary to measure the parameters of housed scintillators with low light output. For that, light flux from housed scintillator is attenuated by a neutral light filter. The pulse heights obtained after attenuation should correspond to the working range of pulse heights of the tested scintillator. Neutral light absorbers are added after the PMT power supply is turned off and the light protection chamber is opened. After setting the light absorber, the chamber is closed, the PMT power supply is turned on and measurements are taken after not less than half an hour’s irradiation. The values of nonlinearity and V o are measured at the same gain factor which is used for measuring the parameters of tested housed scintillator. The nonlinearity and V o should be measured once per month or more frequently, after PMT replacement or assembly repair.
4.2.1 .2 Measurements The test conditions and the order of measurements are in accordance with 4.1 . The value of pulse heights (V) corresponding to total absorption peak maximum is determined. The measurements are repeated three times and the average value V is calculated. All above-mentioned procedures are repeated for each value of energy (E i ). The pulse height spectra may be accumulated simultaneously from all the gamma-emitting sources during irradiation of the housed scintillator.