Eur. Phys. J. A (2007) 34: 363-370
https://doi.org/10.1140/epja/i2006-10522-9

Regular Article - Experimental Physics

Q_β measurements of ^{158, 159}Pm , ^{159, 161}Sm , ^160-165Eu , ¹⁶³Gd and ¹⁶⁶Tb using a total absorption BGO detector

¹ Graduate School of Engineering, Nagoya University, 464-8603, Nagoya, Japan
² Radioisotope Research Center, Nagoya University, 464-8602, Nagoya, Japan
³ Japan Atomic Energy Agency, 319-1195, Tokai-mura, Naka-gun, Ibaraki, Japan
⁴ Graduate School of Engineering, Hiroshima University, 739-8527, Higashi-Hiroshima, Japan
⁵ Research Reactor Institute, Kyoto University, 590-0494, Sennan-gun, Osaka, Japan

^* e-mail: hayashi.hiroaki@b.mbox.nagoya-u.ac.jp

Received: 20 December 2006
Accepted: 16 January 2008
Published online: 6 February 2008

Abstract

Q _β values of the neutron-rich isotopes of ^160-165Eu and ¹⁶³Gd were measured for the first time using a total absorption bismuth germanate (BGO) detector, and previously obtained data on ^{158, 159}Pm , ^{159, 161}Sm and ¹⁶⁶Tb were re-analyzed. These radioactive sources were prepared by an on-line mass separator (Tokai-ISOL) following the ²³⁸U (p,f reaction. The deduced Q _β values are the following: 6085(80)keV for ¹⁵⁸Pm , 3805(65)keV for ¹⁵⁹Sm , 5460(140)keV for ¹⁵⁹Pm , 4705(60)keV for ¹⁶⁰Eu , 5065(130)keV for ¹⁶¹Sm , 3705(60)keV for ¹⁶¹Eu , 5575(60)keV for ¹⁶²Eu , 4690(70)keV for ¹⁶³Eu , 3170(70)keV for ¹⁶³Gd , 6430(70)keV for ¹⁶⁴Eu , 5800(120)keV for ¹⁶⁵Eu , and 4695(70)keV for ¹⁶⁶Tb . Moreover, the deduced mass excesses and two-neutron separation energies ( S _2n values) were compared with those of the atomic mass evaluations and theoretical predictions.