Measurement of dead time of detector using the attenuation law-based method.

Radioactive decays are completely random processes, for accurate detection and quantification of information regarding the source and its strength, we must understand the limitations of our detection systems. The time required to process and enable their detection as two distinct ones are determined as the dead time of the counting system. This comprises all the counting losses taking place due to the detector, and the associated electronics. Two famous models, namely Paralyzable and non-Paralyzable have been determined to predict detector behaviours to some accuracy, but none of them have proved to be perfect. The determination can be useful in determining the detection system’s efficiency, which is of prime importance for the detection and verification of nuclear materials. Some studies have been conducted and reported with the combination of both the models and the attenuation method of dead time determination. Literature review reveals this could be a probable alternative to the existing decaying source and two-source method. While this has the advantages of the non-requirement of a short-lived source and minimal variation in geometry that is incident in the twosource method. In this study, the attenuation method determinesthe detector's dead time with shields of various thicknesses. It is ensured that the Buildup factor is not significant in any of the cases. We have used the Canberra provided basic Labkit having a 22 NaI(Tl) detector with the Osprey-based pulse processing system. The spectra were collected with GENIE 2000 spectroscopy software. It has been observed that as the shield's thickness increases, the detector's dead time increases. This might be explained by the fact that more thermalization of the fast photons is causing more photons to fall on the detector for pulse processing. It also further suggests a minimum thickness that can be employed for the minimal dead time of the setup under consideration.