Progress of Theoretical Physics Supplement No. 146, 2002 575 Coulomb Excitation of 24 Si Shouko Kanno, 1, *) Tomoko Gomi, 1 Tohru Motobayashi, 1 Ken-ichiro Yoneda, 2 Nori Aoi, 3 Yoshiaki Ando, 1 Hidetada Baba, 1 Kimihiko Demichi, 1 Zsolt F¨ ul¨ op, 4 Udai Futakami, 1 Hirokazu Hasegawa, 1 Yoshihide Higurashi, 1 Kazuo Ieki, 1 Nobuaki Imai, 3 Naohito Iwasa, 5 Hironori Iwasaki, 6 Toshiyuki Kubo, 2 Shigeru Kubono, 6 Makoto Kunibu, 1 Yuuichi U. Matsuyama, 1 Shin’ichiro Michimasa, 6 Toshiyuki Minemura, 2 Hiroyuki Murakami, 1 Takashi Nakamura, 7 Akito Saito, 1 Hiroyoshi Sakurai, 3 Masaki Serata, 1 Susumu Shimoura, 6 Takashi Sugimoto, 7 Eri Takeshita, 1 Satoshi Takeuchi, 1 Koji Ue, 6 Kazunari Yamada, 1 Yoshiyuki Yanagisawa, 2 Atsushi Yoshida 2 and Masayasu Ishihara 2 1 Department of Physics, Rikkyo University, Tokyo 171-8501, Japan 2 The Institute of Physical and Chemical Research (RIKEN), Wako 351-0198, Japan 3 Department of Physics, University of Tokyo, Tokyo 113-0033, Japan 4 Institute of Nuclear Research of the Hungarian Academy of Science (ATOMKI), 4001 Debrecen, Hungary 5 Department of Physics, Tohoku University, Sendai 980-8578, Japan 6 Center for Nuclear Study (CNS), University of Tokyo, Saitama 351-0198, Japan 7 Department of Physics, Tokyo Institute of Technology, Tokyo 152-8551, Japan (Received January 15, 2002) We have measured Coulomb excitation of 24 Si to its first excited state to obtain the E2 transition probability. This is the first measurement of B(E2) for a T Z = -2 nucleus, which enables us to compare their transition probabilities between the mirror pair of T = 2, namely 24 Si and 24 Ne. The Coulomb excitation of a proton-rich nucleus 24 Si to its 2 + state was studied using a radioactive beam of 24 Si at 57.9 MeV/nucleon bombarding a 208 Pb target. The beam of 24 Si was produced by using projectile fragmentation of a 28 Si primary beam on a 9 Be production target. The fragments were collected and analyzed by the fragment separator RIPS at RIKEN. The positions and incident angles of the 24 Si nuclei at the target were measured by two sets of parallel-plate avalanche counters (PPAC’s) placed at the third focal plane (F3) of RIPS. Scattered 24 Si nuclei were detected by a counter-telescope placed 60 cm from the target in a vacuum. Sixty-eight NaI(Tl) scintillators, surrounding the target for γ -ray detection, were calibrated for their energy and efficiency by using standard radiation sources. The high granularity of the setup allowed us to measure the angle of the γ -ray emission, which was useful in correcting large Doppler shifts of the γ rays from the excited 24 Si, that was moving with v/c ≈0.3. *) E-mail: komacha@ne.rikkyo.ac.jp Downloaded from https://academic.oup.com/ptps/article-abstract/doi/10.1143/PTPS.146.575/1864270 by guest on 25 May 2020