Date of Award


Degree Type


Degree Name

Master of Science



Major Professor

Geoffrey L. Greene

Committee Members

Robert Grzywacz, Mike Guidry


The NPDGamma collaboration aims to measure a parity{violating directional gamma-ray asymmetry from the capture of polarized cold neutrons on protons. The asymmetry, predicted to be on the order of 50 ppb, is a result of the weak interaction between mesons and nucleons during the neutron capture reaction. The experiment is designed to make a statistics limited measurement of the asymmetry at the level of about 20%. The experiment will be carried out at the Fundamental neutron Physics Beamline (FnPB) at the Spallation Neutron Source (SNS). The neutron beam is polarized by a super{mirror polarizer. A 9.5 G magnetic field guides the neutron spin to a liquid para-hydrogen target, where the neutrons capture forming a deuteron and a 2.2 MeV gamma-ray. The gamma{rays will be detected by a cylin- drical array of CsI scintillating crystals. The beam polarization is reversed with the aid of a resonant RF Spin Rotator (RFSR). This thesis considers different methods for determining the beam polarization and efficiency of the RFSR.

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