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Decay modes of ^9Li and states of ^9Be

Chen, Y. S. and Tombrello, T. A. and Kavanagh, R. W. (1970) Decay modes of ^9Li and states of ^9Be. Nuclear Physics A, 146 (1). pp. 136-148. ISSN 0375-9474.

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The β-decay of the ^9Li nucleus and the subsequent particle decays of the unbound states of the ^9Be nucleus have been investigated with two complementary techniques, a recoil-particle method and a beta-neutron coincidence method. ^9Li nuclei were produced by the ^(18)O(^7Li, ^9Li) ^(16)O reaction at a bombarding energy of 20 MeV and by the ^3H(^7Li, ^9Li)p reaction with a 14 MeV bombarding energy. The energy spectrum of the delayed alphas and the time-of-flight spectrum of the delayed neutrons were obtained. The half-life was measured to be 177±3 ms. Besides the known decay branches to the ground state and to the 2.43 MeV state in ^9Be, a new decay branch to an unbound state in 9Be at an excitation energy of 2.78±0.12 MeV was observed. The branching ratios and the log ft values were found to be (65.0_(−2.4)^(+2.7)) %, (32.0_(−3.7)^(+2.7))%, (3.0_(−0.3)^(+2.7))% and 5.12_(−0.02)^(+0.01), 5.00_(−0.05)^(+0.04), 5.97_(−0.28)^(+0.05) to the ground state, the 2.43 MeV state and the 2.78 MeV state, respectively. The observed properties of the 2.78 MeV state favor an assignment of 1/2. This state decays mainly by neutron emission to the ground state of ^8Be and has a c.m. width of 1.10±0.12 MeV. The fraction of the decays of the 2.43 MeV state in ^9Be involving emission of a neutron to the ground state of ^8Be was found to be (6.4±1.2)%.

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Alternate Title:Decay modes of 9Li and states of 9Be
Additional Information:© 1970 North-Holland Publishing Co. Received 5 January 1970. Supported in part by the National Science Foundation [GP-9114) and by the Office of Naval Research [Nonr-220(47)]. The authors wish to thank Dr. K. Nagatani for his help during the early phase of the recoil-particle experiment, Or. D. C. Hensley and Mr. P. H. Nettles for their generosity in letting us use their i 180 target and Drs. R. F. Christy and T. Lauritsen for helpful discussions. One of us (YSC) also wishes to acknowledge financial support from a General-Atomic Fellowship.
Funding AgencyGrant Number
Office of Naval Research (ONR)Nonr-220(47)
General-Atomic FellowshipUNSPECIFIED
Subject Keywords:Nuclear reactions
Issue or Number:1
Record Number:CaltechAUTHORS:20151106-140715124
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Official Citation:Y.S. Chen, T.A. Tombrello, R.W. Kavanagh, Decay modes of 9Li and states of 9Be, Nuclear Physics A, Volume 146, Issue 1, 4 May 1970, Pages 136-148, ISSN 0375-9474, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:61961
Deposited By: Ruth Sustaita
Deposited On:07 Nov 2015 00:02
Last Modified:03 Oct 2019 09:13

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