K40(n,γ)K41Reaction and the Level Structure ofK41

Abstract
The low-lying level structure of K41 has been studied using the thermal-neutron capture reaction K40(n,γ)K41 on an isotopically separated target of K40. The γ-ray spectrum from this reaction has been studied in the energy range from 0.1 to 10.1 MeV using a Li-drifted Ge spectrometer system. γγ coincidence measurements using Ge(Li) detectors have also been made. Spin and parity assignments for the excited states below 2450 keV are proposed, primarily on the basis of γ-ray branching to levels with established spin and parity values. The proposed level energy [keV (Iπ)] values are 0(32+), 980.4(12+), 1293.4(72), 1559.9(12+), 1582.0(52+), 1677.5(52+,72+), 1698.1(52±,72+), 2144.1(52+), 2166.0(12+,32±), 2316.5(52+,72+), 2447.9(12±,32±). Additional levels have been observed at 2494.7, 2507.9, 2527.9, 2599.8, 2681.5, 2712.2, 2756.5, 2760.7, 3042.1, 3142.1, 3164.5, 3213.4, 3235.6, and 3281.1 keV. These low-lying excited states of