PMS-1, Geometry and Multiple Scattering Correlation to Experimental Polarization Data by Monte-Carlo

1 - Description of problem or function: PMS1 corrects experimental fast neutron polarization data for finite geometry and multiple scattering effects, when liquid helium is the polarizer analyzer. 2 - Method of solution: The Monte Carlo code simulates the actual geometry of the experiment, traces scattering histories to estimate multiple-scattering asymmetry for an incident neutron beam of arbitrary polarization. The code uses phase shifts to calculate the necessary parameters, the angular distributions (d sigma)/(d omega), the polarization p and the spin rotation parameter beta needed for consistent tracking of polarization effects in successive scattering. The phase shift data are taken from the fitted data of Hoop and Barschall above 1.5 MeV and from Morgan and Walter below 1.5 MeV. The code adjusts the initial input polarization needed to reproduce the measured left-right count ratio for the two detectors. 3 - Restrictions on the complexity of the problem: No more than five collisions are allowed and liquid helium must be the polarizer analyzer. The total number of energy points for which phase shifts are given must be less than 100