Radiative Capture of Protons by Be9
The gamma rays from the capture in Be9 of protons of energy between 0.27 and 1.2 Mev have been studied using large scintillation crystals. Excitation functions of the gamma rays leading to the 0-, 0.72-, 1.74-, 2.15-, 3.58-, and 5.16-Mev states of B10 were computed from the measured gamma-ray spectra. In addition to the resonances previously known to exist at 0.33-, 0.99-, and 1.086-Mev proton energy [corresponding to (1-) 6.88-, (2-) 7.48-, and (0+) 7.56-Mev states in B10], evidence was found only for the p-wave resonance near 1 Mev [(2+) 7.5-Mev state in B10] postulated by Mozer and by Dearnaly and for the influence of higher lying states. This work leaves unexplained the large isotopic-spin impurity of the 6.88-Mev level. Appreciable nonresonant capture was found for the transitions to the 0-, 0.72-, 3.58-, and 5.16-Mev states, which is probably not s-wave for the latter two transitions. Accurate energy measurements and coincidence work showed that the 5.16-Mev level of B10 is populated in preference to the 5.11-Mev level, contradicting earlier work of Clegg. Also, experimental evidence has been found which appears to be in contradiction to the 0+ spin assignment for the 7.56-Mev level of B10 and raises doubts about the 2+ spin assignment of the 5.16-Mev level.
©1959 The American Physical Society Received 13 April 1959 Two of us (W.E.M. and C.M.H.) would like to express our gratitude to Professor C.C. Lauritsen for allowing us to work at the Kellogg Radiation Laboratory of the California Institute of Technology. The encouragement of Professor W.A. Fowler as well as discussions with Dr. A.B. Clegg, Dr. G. Dearnaly, Dr. S.S. Hanna, Dr. G.A. Jones, and Professor D.H. Wilkinson are gratefully acknowledged. We appreciate very much the loan of equipment and help received from Dr. R.W. Kavanagh. Also, one of us (W.E.M.) is very grateful to the Alfred P. Sloan Foundation for the grant of a fellowhsip during 1957-1958, which made this work possible, and for other support. Assisted in part by a grant of the Alfred P. Sloan Foundation, Inc., to Stanford University and by the joint program of the Office of Naval Research and the U.S. Atomic Energy Commission at the California Institute of Technology and at Stanford University. Experimental work performed at the Kellogg Radiation Laboratory, California Institute of Technology. [W.E.M. was an] Alfred P. Sloan Foundation Fellow, 1957-1958. Senior Research Fellow at the California Institute of Technology, 1957-1958.