Gamma-Ray Spectra and Level Structure ofCa44from Thermal-Neutron Capture inCa43

Abstract

$\gamma$-ray measurements have been made of the ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}(n,\gamma ){}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$ reaction at the Livermore pool-type reactor. Singles spectra were taken with Ge(Li)-NaI(Tl) Compton-suppression and pair-coincidence spectrometers. A total of 280 observed $\gamma$ rays were attributed to capture in ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$. Ge(Li)-Ge(Li) coincidence measurements using a three-parameter analyzer system ($E_1,E_2,\Delta T$) were analyzed, resulting in the assignment of 129 of the observed transitions to 45 inferred levels in ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$. Comparison of $l=1\mathrm{} \mathrm{}(d,p)\mathrm{}$ strengths $\mathrm{}(2J+1)\mathrm{}{S}_n$ with ($n,\gamma$) strengths $\frac{I}{E^3}$ leading to the same final states yields a positive correlation coefficient of 0.63. The neutron binding energy is determined to be 11 131.6 ± 0.7 keV.