Investigation of 41Sc by proton capture in 40Ca

Abstract

Resonance strengths, excitation energies and γ-ray branching ratios have been measured of twenty 40Ca(p, γ) 41Sc resonances observed in the E p = 640–3500 keV region. The reaction Q-value is determined as Q = 1085.07 ± 0.09 keV. A previously not reported 41Sc level is found at E x = 3.01 MeV; it is the missing mirror state of 41Ca(3.05 MeV). Gamma-ray angular distributions, measured at three selected resonances, lead to the assignments J π = 3 2 +, 7 2 + and 7 2 − to the E x = 2.10, 3.70 and 4.03 MeV levels, respectively. A spin J π = 3 2 − is assigned to the E x = 2.41 MeV level on the basis of transition strength arguments. These new data allow a rather detailed comparison of the mirror states of 41Ca and 41Sc. Shell-model calculations are performed for the A = 38–42 mass region, based on a ( 2 s 1 2 1 d 3 2 )-(1f 7 2 2 p 3 2 ) configuration space with up to three (four for A = 40) particles excited from the sd to the fp shell. Both positive- and negative-parity states are considered. Excitation energies and transition strengths of A = 41, T = 1 2 nuclei are calculated and compared to the experimental data.