Dead time and count loss determination for radiation detection systems in high count rate applications
"This research is focused on dead time and the subsequent count loss estimation in radiation detection systems. The dead time is the minimum amount of time required between two events to permit detection of those events individually by a radiation detection system. If events occur during the system dead time, they are lost. Such lost information can be important in many applications including high-precision spectroscopy, positron emission tomography (PET), and the scanning of spent nuclear fuel. Understanding of the behavior of radiation detection systems is important; thus this work included a comprehensive review of dead time and pulse pile-up models and methods. The most common way to estimate detector dead time is by one-parameter approximations known as nonparalyzable and paralyzable models. This research proposes a two parameter model that estimates the detector paralysis factor and the dead time based on a graphical method. To determine the two parameters characteristics of a detection system, this work tested a novel technique to saturate the detector using a decaying source. The modified decaying source method, unlike other methods, does not assume the idealized behavior of detection system in use and calculates the overall dead time of the detection system. The paralysis factor for high purity germanium detection system was estimated approaching 100% and the dead time was on the order of 5-10 µs which compares well with the literature"--Abstract, page iv.
Missouri University of Science and Technology
Networked Digital Library of Theses and Dissertations