Gamma-ray production cross sections have been measured for the gamma-ray lines most strongly excited in the proton bombardment of "C, "N, ' 0, ' Ne, "Mg, "Si, and '6Fe, for proton energies from threshold to 23 MeV. I addition, cross sections for the "N(p, n) "0 and "Fe(p,n)"Co reactions were determined from delayed gamma-ray yields. Ge(Li) detectors were used. Tabulations of cross sections averaged over proton energy bins of 1 MeV and over power law distributions in proton energy are provided for calculations relevant to gamma-ray line astronomy.Examples are given of astrophysical information which might be extracted from spectra acquired with gamma-ray spectrometers in space, using these cross sections, e.g. , parameters describing the energy distribution of incident protons.NUCLEAR REACTIONS p+'2C, '4N,~~0, Ne, 24Mg 288i +Fe t4N(P n) +Fe(p, n j. E= threshold to 23 MeV. Measured y production cross sections.Applications to y line astronomy.

Angular distributions of deuterons from Li 7 (^,^)Li 6 reactions induced by 17.5-Mev protons on a natural lithium target have been observed at angles less than 50 degrees in the laboratory system. Deuteron groups leaving Li 6 in its ground state and in states at 2.19 and 3.57 Mev were studied, and the branching ratios were compared with intermediate coupling shell theory. Pure or nearly pure L-S coupling was found to be adequate to explain the observed ratios.

T HE ratio T n°/ D of the reduced neutron width divided by the level distances, when averaged over low-lying resonance levels (usually referred to as neutron-strength function), shows a characteristic behavior as a function of A with maxima near A n^5 5 and ,4 n~1 70. These maxima come from the establishment of standing waves within the nucleus whenwhere K n is the wave number of the incoming particle within nuclear matter for particles with zero incident energy; V n is the depth of the nuclear potential well for neutrons which, in first order, is considered constant over the nucleus. Similar maxima should occur for the proton strength function T p°/ D, as was pointed out by Schiffer and Lee. 1 In this case T p° is the reduced proton width, which is the actual width corrected for Coulomb penetration and reduced to a fixed energy. However, the potential well V v for protons is different from V n on two accounts. It is less deep than the well for neutrons, and the part which comes from the electrostatic force has a characteristic variation with the radial coordinate r. We have, in fact,We therefore get for protons an equation similar toWe obtain a simple estimate of V p and V n from the separation energies S n and S p of neutrons or protons.The following relation must hold: TF+S=V, where TF is the kinetic energy on top of the Fermi distribution : T F = l(9/2)Tj(W/2mr 0 2 ) (n/2A)l=C(n/2A)*.Here m is the mass of a nucleon, ro is given by R=roA$, and n is the number of protons or neutrons, respectively. Hence, we get V p /V n = KTp^+SpyiTFln+Sn], and from this formula K p rC(n p /2Ay>+S p -(2/15)(Ze 2 /R)}l -= • (2) K n L C(n n /2A)*+S n J The ratio of the values of A at which maxima occur is then given by (A p /A n )= (K n /K p )\ Expression (2) can be roughly evaluated for nuclei 55<^<70 by putting r 0 =1.2 (C=^83.3 Mev), 5p«5 n «8 Mev, (n p /2A) = 0.225 and (n n /2A) = 0.275.We then get (A p /A n ) = 1.24c, and, with the well-known value of ^4 n~5 5, we expect A p~6 8. According to these rough estimates the next maximum can be expected near A p~2 30. Recent measurements by Schiffer and Lee 1 seem to bear out the prediction of a maximum near ^4 = 68.T HE positron-neutrino angular correlation coefficient has been measured for the decay of A 35 . Since this decay occurs mainly through the Fermi matrix element, 1 the correlation should be sensitive to the ratio of the two Fermi coupling constants |gF 2 |/|gs 2 |. Two different experiments have been carried out, and in each case, the results have shown that the vector interaction is dominant.A 35 has a half-life of 1.8 sec and decays by the emission of positrons with a maximum kinetic energy of 4.9 Mev into its mirror nucleus CI 35 . Although most of the beta transitions go to the ground state of CI 35 , about 7% of the decays go through beta transitions to the first two excited levels of CI 35 which then decay by emission of gamma rays. 1 The A 35 was produced by the reaction S 32 (a,w)A 35 in a target of gaseous SF6. A steady stream of SF6 carried the radioactive A...

The electron-neutrino angular correlation in the beta decay of Ne 19 has been measured by observing the energy spectrum of F 19 recoil ions. The constant X in the angular correlation function [l+Xfe/c) eos0 6 J was found to be \= -0.21 ±0.08, indicating that the beta-decay interaction is of the form STP and not VTP. The observed angular correlation leads to the result c^l/^V^/H*" 0,69 * 0 ' 17, which is consistent with Cs 2 -Cr 2 if the nuclear configuration is (d 5 / 2 ) 3 i/2, but not if the configuration is (si/2) 3 i/2. Most of the F 19 recoils carried one unit of negative charge, but singly charged positive ions were also detected. The coincidence rate due to positive ions was about 10 percent of that due to negative ions.