title: Gamma geometry dependency of efficiency functions in the 4πβ-γ coincidence measurements of complex decaying nuclides.
abstract: In order to clarify the γ-efficiency dependency of 4πβ-γ efficiency functions, a series of 4πβ-γ efficiency extrapolation measurements of a (134)Cs source were carried out for a wide variety of γ-geometries using a 4πβ(PS)-4πγ detector configuration. As the source is situated in the plastic scintillator (PS) β-detector, the γ-efficiency of the system can be readily changed by extracting the β-detector from the well-hole in a series of stages. For data acquisition and analyses, a list-mode two-parameter data acquisition system was employed. The forms of the extrapolation curves were monitored with decreasing γ-geometry, eventually exhibiting a similar behavior to those obtained in a usual 4πβ-γ coincidence counting system. The experimental results and considerations suggested that the γ-geometry dependency of the efficiency functions were due to summing effects in the γ-channel, and some qualitative remarks on the form of the extrapolation functions are given.
authors.affiliation: National Metrology Institute of Japan, National Institute of Advanced Sciences and Technology, Tsukuba Central 2, 1-1-1 Umezono, Tsukuba 305-8568, Japan. Electronic address: kawada.t4@gmail.com.
authors.forename: Y
authors.initials: Y
authors.lastname: Kawada
authors.affiliation: National Metrology Institute of Japan, National Institute of Advanced Sciences and Technology, Tsukuba Central 2, 1-1-1 Umezono, Tsukuba 305-8568, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Yunoki
authors.affiliation: National Metrology Institute of Japan, National Institute of Advanced Sciences and Technology, Tsukuba Central 2, 1-1-1 Umezono, Tsukuba 305-8568, Japan; Japan Radioisotope Association, 2-28-45, Hon-Komagome, Bunkyo, Tokyo 113-3941, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yamada
authors.affiliation: National Metrology Institute of Japan, National Institute of Advanced Sciences and Technology, Tsukuba Central 2, 1-1-1 Umezono, Tsukuba 305-8568, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hino
keywords: (134)Cs; 4πβ-γ coincidence counting; Efficiency function; Geometrical dependency; Pulse-height summing; Software coincidence