Abstract: There is dead time in the measurement of radiation by any detector. When the radiation intensity is too high and the current radiation has not been fully processed by the detector, the following radiation may not be processed, resulting in the loss of count. In practical measurement, it is necessary to accurately measure the count rate of the radiation and it is necessary to correct the dead time effect. In this paper, the dead time of the NaI(Tl) detector based on digital multichannel analyzer is analyzed theoretically and the correction method is studied. The dead time is measured by the dual source method and the effectiveness of the correction method is verified in ¹³⁷Cs radiation field.

Key words: dead time, dual source method, digital multichannel analyzer