The structure of high-spin positive-parity states in ⁴³Ca

Abstract

The ⁴⁰Ar(α, nγ)⁴³Ca reaction has been used to study high-spin states in ⁴³Ca. The γ-ray decays of levels at 3505 and 4186 keV are established in γ-γ coincidence measurements and new decays are observed from levels at 3944 and 4591 keV. Solid Ar targets enable the Doppler shift attenuation method to be used to measure mean lifetimes for the following levels $\text{E}{}_{\mathrm{<mtext>x</mtext>}}\text{(}\text{keV}\text{)(τ}{}_{\mathrm{m}}\text{)J}{}^{\mathrm{\pi }}\text{: 2951(>5}\text{ps}\text{)}\text{11}\text{2}{}^{\mathrm{+}}$; $\text{3371(>5}\text{ps}\text{)}\text{13}\text{2}{}^{\mathrm{+}}$; $\text{3505 (105±35}\text{fs}\text{)}\text{13}\text{2}{}^{\mathrm{+}}$; $\text{3944 (1.1±0.3}\text{ps}\text{)}\text{15}\text{2}{}^{\mathrm{+}}$; $\text{4186 (180±70}\text{fs}\text{)}\text{15}\text{2}{}^{\mathrm{+}}$ and $\text{4591 (300±75}\text{fs}\text{) (}\text{13}\text{2}{}^{\mathrm{+}}\text{,}\text{17}\text{2}{}^{\mathrm{+}}\text{)}$. The structure of these levels is discussed in terms of a deformed $\text{K}{}^{\mathrm{\pi }}\text{=}\text{3}\text{2}{}^{\mathrm{+}}$ band and shell model configurations of the type .