Muonuclear Absorption and the Factorization Method

Muon absorption by a nucleus [μ− + [Z,A] → [Z – 1,A]* + vμ] is treated in the framework of a factorization method already tested in photonuclear physics. The transition rates to various states 0−,1−,2− of the final nucleus [Z – 1,A]* and the energy spectra of the subsequent outgoing neutrons are analyzed in the case of 16O and 40Ca.

The 149,151Sm(p,t)147,149Sm Reactions

Two-neutron pickup reactions have been performed on targets of 149Sm and radioactive 151Sm using 18 MeV protons. The outgoing tritons from the 151Sm target were analyzed with a magnetic spectrograph at 16 angles between 6 and 80°. Unlike the two-neutron transfer data on neighboring even–even targets, the angular distributions indicated l = 0 transitions to many levels in the final nucleus. Partial angular distributions for the 149Sm(p,t)147Sm reaction were obtained, but showed only one strong l = 0 transition populating the 147Sm ground state. In addition, spectra from the 152Sm(p,t) reaction were measured at several angles in order to provide normalization to previous results.

Information on Energy Levels in 8Be from Neutron Energy Spectra

A number of measurements have been made of the neutron energy spectra emitted in the reaction 7Li(d, n)8Be, and, as is the case for other reactions leading to the same final nucleus, contradictory conclusions have been reached as to the number of levels observed.

K -electron capture, nuclear isomerism and the longperiod activities of titanium and scandium

Recent work in the field of induced radioactivity has revealed a number of interesting phenomena. Thus it has been shown that certain nuclei which emit positrons may also transform to the same final nucleus by capturing an electron from the extra-nuclear structure. Another effect, closely linked with this, and for which experimental evidence has recently been obtained, is that if two nuclei with the same atomic weight A (isobars) but with atomic numbers Z and Z + 2 respectively, are both stable, the intermediate nucleus of atomic number Z + 1 (atomic weight A ) is unstable with respect to both of them and so decays by “ branching”. The intermediate nucleus in general transforms to the nucleus of atomic number Z by electron capture and to the nucleus of atomic number Z + 2, by emitting a negative electron. More unexpected amongst recent results is the not uncommon occurrence of nuclei with the same atomic number and atomic weight but with different activities. This is known as nuclear isomerism. Before its discovery in induced radioactivity its existence was, however, already known from Hahn’s work on the naturally radioactive substances uranium Z and uranium Y .