International Conference on Nuclear Data for Science and Technology 2007
DOI: 10.1051/ndata:07458

Half-life of ¹⁸⁴Re populated by photodisintegration reaction with Laser Compton scattering γ-rays at NewSUBARU

T. Hayakawa^{1, 2}, S. Miyamoto³, Y. Hayashi¹, K. Kawase⁴, K. Horikawa³, S. Chiba⁵, K. Nakanishi⁴, H. Hashimoto⁴, T. Ohta⁴, M. Kando¹, T. Mochizuki³, T. Kajino² and M. Fujiwara<sup>1, 4

1</sup>  Kansai Photon Science Institute, Japan Atomic Energy Agency, Kizu, Kyoto 619-0215, Japan
²  National Astronomical Observatory, Osawa, Mitaka, Tokyo 181-8588, Japan
³  University of Hyogo, Hyogo 678-1205, Japan
⁴  Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047, Japan
⁵  Advanced Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan

hayakawa.takehito@jaea.go.jp

Published online: 21 May 2008

Abstract
We report a half-life of the ground state of ¹⁸⁴Re populated by the ¹⁸⁵Re(γ,n)¹⁸⁴Re reaction with the Laser Compton scattering γ-rays generated through relativistic engineering. The γ rays are provided at the electron storage ring NewSUBARU. The half-life of the 3^- ground state of ¹⁸⁴Re, 38.0 ± 0.5 d, has been taken as a recommended value, which was measured using deuteron-induced reactions. However, this half-life may include a possible contribution from the 8⁺ isomer (T_1/2 = 169 ± 8 d) of ¹⁸⁴Re since the presence of the isomer was not known at that time. In contrast, the (γ,n) reaction has the advantage to selectively populate the ground state because this reaction does not bring large angular momentum. The measured half-life of 35.4 ± 0.7 d is shorter than the previous half-life by about 7%. This difference is crucial for applications using the activation method.

© CEA 2008