Circular polarization of neutron capture γ-rays from Al, Ar and Ca

Abstract

Measurements of the circular polarization of γ-rays from the capture of polarized thermal neutrons in natural Al, Ar and Ca result in new spin assignments to the following bound states: 28Al(3.47 MeV), J π = 4 -; 28Al(3.59), J π = 4 −(2) −; 41Ar(2.95), J π = 3 2 − J π = 3 2 − . The 41Ca levels at 3.61 and 4.75 MeV, for which conflicting spin values have been reported previously, both have J π = 1 2 − . The spins of 10 other bound states are confirmed. The M1 + E2 ground state transition from the capturing state in 28Al has an amplitude mixing ratio of δ = +1.00±0.14.