Gamma-ray polarization measurements in 22Na

Abstract

The 19F(α,nγ)22Na reaction was studied using a Ge(Li) single-crystal polarimeter in addition to conventional Ge(Li) counters to elucidate certain spin, parity, and multipole-mixing ratio assignments to low levels of 22Na. The 1.984 MeV level, which had previously been assigned 2+ or 3+, has been shown not to be 3+ and, while 2+ is favored by the experiment, the evidence tends to suggest a problem in the interpretation of the properties of this level. The 2.572 MeV level is shown most likely to have spin and parity 2+. The J = 2 level at 3.059 MeV is clearly established as having even parity. In several cases limits on mixing ratios are obtained. These results cast doubt on certain model identifications made recently in 22Na.