International Conference on Nuclear Data for Science and Technology 2007
DOI: 10.1051/ndata:07460

Q_β measurements of neutron-rich isotopes with a total-absorption type Ge detector using the KUR-ISOL

Hiroaki Hayashi¹, Itaru Miyazaki¹, Michihiro Shibata², Yasuaki Kojima³ and Akihiro Taniguchi<sup>4

1</sup>  Graduate School of Engineering, Nagoya University, Nagoya, 464-8603, Japan
²  Radioisotope Research Center, Nagoya University, Nagoya, 464-8602, Japan
³  Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima, 739-8527, Japan
⁴  Research Reactor Institute, Kyoto University, Sennan-gun, Osaka 590-0494, Japan

h052304d@mbox.nagoya-u.ac.jp

Published online: 21 May 2008

Abstract
To measure Q_βs of neutron-rich nuclei far from the stability, the total-absorption-type Ge detector has been developed. The detector is composed of a large true-coaxial type HPGe detector and an annular BGO scintillation detector for the Compton suppression. To check the detector performance, nineteen nuclides having precisely measured Q_βs are measured. The nuclei of interest were prepared by (n, γ) reactions and 235U(n,f) reactions using the Kyoto University Reactor (KUR). The response functions of γ-rays and monoenergetic electrons were calculated by means of the Monte Carlo simulation code (EGS4), and the folding method was used to deduce Q_βs. The nuclei ^147-149La, ¹⁵¹Ce, and ¹⁵³Pr, for which precise information of the decay schemes were not reported, were prepared by the on-line mass separator (KUR-ISOL) and were measured by the total-absorption type Ge detector. The deduced Q_βs were consistent with preliminarily measured ones by a total absorption BGO detector. The evaluated values by Audi et al. were systematically smaller than the present ones.

© CEA 2008