Nuclear structure investigations in medium-light nuclei

Abstract

A variety of nuclear spectroscopy techniques have been used to investigate nuclei with mass numbers between 22 and 54. The recoil-distance method is discussed in detail, particular attention being paid to second-order corrections, and analysis of cascade-fed and low-energy transitions. The γ-γ coincidence technique and spain assignments using γ-ray angular distributions are also discussed. The lifetimes of five excited states in 22Na, one in 22Ne, one in 30Si and three in 30P have been remeasured by the recoil-distance method. The lifetimes extracted are discussed and compared to previous measurements. The states of 46Ti have been studied using the 43Ca(α,nγ) reaction. The level and decay scheme of 46Ti was deduced from γ-γ coincidence, γ-ray energy and intensity measurements. Spins are suggested on the basis of the γ-ray angular distributions, supported by relative excitation functions. The ground state band has been extended to spin 10+, and about 20 new states are observed. Some of these can be grouped into rotational-like bands based on the 3- state at 3.059 MeV and other excited states. The Doppler-shift attenuation method has been used in conjunction with a solid argon target and p-γ coincidences following the 40Ar(d,p) reaction to determine the lifetimes or obtain lifetime limits for six levels in 41Ar. In addition, singles γ-ray measurements with both solid and gas targets were made, and lifetimes or lifetime limits for a further two levels in 41Ar and nine in 41K were extracted. These results are discussed and compared to previous measurements. The recoil distance method has been used to investigate the lifetimes of four excited states in 54Mn and four in 53Cr. In addition, γ-ray angular distributions following the 50Ti(α,n) and 51V(α,n) reactions have been measured, and the Doppler-shift attenuation method has been used to investigate fourteen lifetimes in 54Mn and ten in 53Cr. The results extracted are discussed, and compared to previous experiments and to theoretical predictions.