A nuclear reaction polarimeter using position-sensitive particle detectors

Abstract

Position-sensitive solid-state detectors have been used in double-scattering experiments with solid targets. Particles with second scattering angles θ 1ab from 36° to 144° were observed simultaneously by two of these detectors. Left-right asymmetries were obtained for each detector from consecutive measurements with the detector on opposite sides of the incident beam. A digital computer was used to accumulate data as two-parameter spectra, the two parameters being the positions and energies of the detected particles. Events were labelled to indicate the detector in which they occured. The polarimeter was used initially to scatter protons twice from 12C. Three sets of measurements were made, so the polarizations were determined (except for a sign) independently of other measurements. A sample angular distribution is shown for the measured polarization of protons elastically scattered from 12C at 6.14 MeV. The data were corrected for the false asymmetry due to the finite geometry. A simple but general calculation is described to make this correction for any polarimeter using two solid targets.