A proton polarimeter for 3He(d,p)4He polarization transfer studies

A compact polarimeter has been constructed and calibrated to measure the polarization of 13–16 MeV protons, such as those emitted from the 3He(d,p)4He reaction near the Ed=430 keV resonance. The polarimeter uses p-4He elastic scattering as an analyzer. It consists of a 4He gas cell pressurized to 2.76 MPa and a left–right pair of CsI detectors collimated at 65° to maximize the figure of merit for the device. The effective analyzing power and efficiency of the polarimeter have been measured as a function of energy using a collimated polarized proton beam. These measured values are in good agreement with a Monte Carlo computer simulation that forms the basis for the calibration curve for the device. Preliminary results from the 3He(d,p)4He reaction with polarized deuterons confirm that the proton polarimeter can be used to determine polarization transfer coefficients near the low-energy resonance.