New Method for Precision Positron Polarimetry: First Results and Future Applications

A new instrument capable of precisely comparing the polarization of positrons from the decay of different nuclei is described. The decays of ${}_{}{}^{22}{}_{}{}^{}\mathrm{Na}$ and ${}_{}{}^{68}{}_{}{}^{}\mathrm{Ga}$ have been compared to 1% accuracy with a first-generation instrument. Systematic studies indicate that an eventual accuracy of 4×${10}^{-4\mathrm{}}$ can be reached, allowing improved limits to be set on parity-symmetric formulations of the weak interactions.