Measurement of the polarization-asymmetry correlation for 21Na with novel target and polarimeter

Measurements of the Polarization-Asymmetry Correlation (PAC) in nuclear beta decay require samples of high polarization and activity which are well coupled to an efficient polarimeter. We have developed a system to accomplish this and used it in preliminary PAC measurements on 21Na. The 21Na nuclei were produced with the 20Ne(d,n)21Na reaction in a 20Ne gas target and polarized by optical pumping with a laser system. The positron polarization was extracted from lifetime spectra of positronium formed in the presence of a strong magnetic field. This is the first measurement of its type for a superallowed transition.