Monte Carlo Simulation of the NSR Collaboration apparatus at NIST*

The NSR collaboration has designed a neutron spin polarimeter to measure deviations in the average spin rotation of a beam of neutrons in the range of 1E-7 rad/m. The collaboration is considering using this polarimeter at the NGC arm of the NIST reactor to carry out experiments to test a predicted class of short-range spin dependent forces that affect neutron polarization as they pass close to other dense masses of baryons. If these forces are demonstrated to exist, this would extend the standard model of particle physics. Over the summer we adapted a Monte Carlo simulation of the instrument in MCSTAS to use the NGC neutron phase space and gauge the ability of the MCSTAS instrument to accurately measure pre-determined tilts we put in the neutron beam. We also investigated possible systematic errors due to spin rotations from magnetic fields by looking at changes in the neutron beam's angular and wavelength distributions downstream from the target as a function of target configuration.