Reinvestigation of the direct two-proton decay of the long-lived isomer 94Ag(m) [0.4 s, 6.7 MeV, (21+)].
Reinvestigation of the direct two-proton decay of the long-lived isomer 94Ag(m) [0.4 s, 6.7 MeV, (21+)].
复制标题
DOI：
10.1103/physrevlett.103.152502
复制
发表时间：
2009-10
影响因子：
8.6
通讯作者：
J. Cerny;D. Moltz;D. Lee;K. Peräjärvi;B. Barquest;L. Grossman;W. Jeong;C. Jewett
中科院分区：
文献类型：
--
作者：
J. Cerny;D. Moltz;D. Lee;K. Peräjärvi;B. Barquest;L. Grossman;W. Jeong;C. Jewett
已尝试确认 94Ag 中 6.7(5) MeV 处 (21+) 异构体的直接一质子和二质子衰变。该异构体的半衰期为 0.39(4) s，允许使用氦喷射系统将 40Ca + (nat)Ni 反应的反应产物以 197 MeV 传输至低本底区域；使用 24 台气体 DeltaE-(Si)E 探测器望远镜来识别低至 0.4 MeV 的发射质子。没有获得总能量为 1.9(1) MeV、支化比为 0.5(3)% 的二质子放射性的证据。还报道了该异构体的两组单质子放射性；我们的数据证实较低能量组为 0.79(3) MeV，其支化率为 1.9(5)%。
An attempt to confirm the reported direct one-proton and two-proton decays of the (21+) isomer at 6.7(5) MeV in 94Ag has been made. The 0.39(4) s half-life of the isomer permitted use of a helium-jet system to transport reaction products from the 40Ca + (nat)Ni reaction at 197 MeV to a low-background area; 24 gas DeltaE-(Si)E detector telescopes were used to identify emitted protons down to 0.4 MeV. No evidence was obtained for two-proton radioactivity with a summed energy of 1.9(1) MeV and a branching ratio of 0.5(3)%. Two groups of one-proton radioactivity from this isomer had also been reported; our data confirm the lower energy group at 0.79(3) MeV with its branching ratio of 1.9(5)%.