Lifetime measurements of first excited states in {sup 16,18}C

Journal Article · Tue Jul 15 04:00:00 EDT 2008 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.78.014308· OSTI ID:21192025

Ong, H J ^[1]; Imai, N; Takeuchi, S; Aoi, N; Baba, H; Bishop, S; Ishihara, M; Kubo, T; Motobayashi, T; Yanagisawa, Y ^[2]; Suzuki, D; Iwasaki, H; Sakurai, H; Onishi, T K; Suzuki, M K; Nakao, T; Ichikawa, Y ^[1]; Ota, S ^[3]; Togano, Y; Kurita, K ^[4]

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1. Department of Physics, University of Tokyo, Hongo 7-3-1, Bunkyo, Tokyo 113-0033 (Japan)
2. RIKEN Nishina Center, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan)
3. Center for Nuclear Study, University of Tokyo, RIKEN campus, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan)
4. Department of Physics, Rikkyo University, Nishi-Ikebukuro 3-34-1, Toshima, Tokyo 171-8501 (Japan)

The electric quadrupole transition from the first 2{sup +} state to the ground 0{sup +} state in {sup 18}C was studied through a lifetime measurement by an upgraded recoil shadow method applied to inelastically scattered radioactive {sup 18}C nuclei. The measured mean lifetime is 18.9{+-}0.9(stat){+-}4.4(syst) ps, corresponding to a B(E2;2{sub 1}{sup +}{yields}0{sub g.s.}{sup +}) value of 4.3{+-}0.2{+-}1.0 e{sup 2} fm{sup 4}, or about 1.5 Weisskopf units. The mean lifetime of the first 2{sup +} state in {sup 16}C was remeasured to be 18.3{+-}1.4{+-}4.8 ps, about four times shorter than the value reported previously. The discrepancy between the two results was explained by incorporating the {gamma}-ray angular distribution measured in this work into the previous measurement. These transition strengths are hindered compared to the empirical transition strengths, indicating that the anomalous hindrance observed in {sup 16}C persists in {sup 18}C.

• OSTI ID: 21192025
• Journal Information: Physical Review. C, Nuclear Physics, Journal Name: Physical Review. C, Nuclear Physics Journal Issue: 1 Vol. 78; ISSN 0556-2813; ISSN PRVCAN
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ANGULAR DISTRIBUTION
CARBON 16
CARBON 18
E2-TRANSITIONS
EXCITED STATES
GAMMA RADIATION
LIFETIME
RECOILS