Properties of theT3(p,γ)He4Reaction

Abstract

Yield and angular distribution measurements on the T 3 (/>, 7)He 4 reaction have been made for protons up to 2.5 Mev. The yield indicates a resonance in the He 4 nucleus at a proton energy of about 2.5 Mev, giving an excited level at 21.6 Mev. The angular yield of the gamma-rays fits an A-\-B sin 2 # distribution very well, suggesting that the gamma-rays are due predominantly to a transition from the x Pi state to the 1 SQ state. An aluminum absorption curve for the secondaries produced in a lead radiator was taken, and a direct comparison made with the 17.5-Mev gamma-rays from the Li 7 (p, 7)Be 8 reaction, showing that the T 3 (/>, 7)He 4 gamma-rays are of higher energy.

Fine Structure in the Energy Spectra of Photoprotons fromHe4

“…No evidence has been found for transitions other than that to the ground state of He 4 . Experiments on the yield of the T(p,y) have been performed with protons up to 2.6 Mev by Argo et al, 7 The relative probability of forming each member of a pair of nuclear isomeric states has been compared with theoretical predictions in order to learn which nuclear parameters can be determined from these data. For thermal neutron capture reactions, the observed ratios do not give much information about the dependence of the nuclear level density on spin, but they are consistent with a spin cutoff factor, exp[-(/+i) 2 /2o-2 ], where a-<5.…”

The scattering of nucleons by alpha-particles

“…These states were in accord with current theoretical ideas (Feenberg 1936, Bethe andBacher 1936), but later work on the reaction of deuterons with helium 3 (Allred 1950, Hatton andPreston 1949) set, lower limits of 20:9 Mev and 18.3 ~mv respectively on the lowest excited state of the alpha-particle. Further investigations of the reactions of neutrons and protons with tritium (TaSehek et al 1949, Argo et al 1950, however, provided evidence for an excited state at 21.6 ~ev. Downloaded by [UQ Library] at 13:08 03 February 2015 I:[eydenburg* 1941Keitler* 1947Freier* 1949Bradeu 1951, 1.q53 Putnam 1952Kreger* 1952, Atkins 1952Wickersham 1954, 1957Cork* 1954Freemantle* 1954' Williams* 1955Teem* I955 Eisberg 1956Brockman 1956Putnam* 1956a,b Vanecian 1956Chamberlain* 1956Miller* I957 Brussel* 1957Tyren* 1957 S.C.…”

Theory of Internal Conversion

“…Argo et al 1 made a similar yield comparison, except that they observed at 90 degrees and used a detector which counted the 14.8-Mev lithium line also. Adjusting 11 -12 our value to their conditions would give a ratio of 0.012, while they 13 obtain 0.043.…”

“…(8) the order of writing factors has been chosen such that the summations refer to repeated subscripts which are adjacent. Now, to the same relative order in e 2 the probabilities of observing electrons and photons are, respectively, N e = TT3(7I+72)-1 I H u0 1 2 SI ff«* (l) ~ v&LZHukHtoHvkV | 2 , (9) N q = 7r( 7 i-f Y2)- 1 …”

“…(London) A142, 215 (1933), henceforth referred to as TM.3 Appendix B, Sec. 4, of TG.4 The superscript(1) indicates that in the matrix element a hankel function of the first kind replaces the bessel function. Similarly, we signal the presence of a hankel function of the second kind by a superscript(2).…”