Performance of the neutron polarimeter NPOL3 for high resolution measurements

We describe the neutron polarimeter NPOL3 for the measurement of polarization transfer observables Dij with a typical high resolution of ∼300 keV at Tn ≃ 200 MeV. The NPOL3 system consists of three planes of neutron detectors. The first two planes for neutron polarization analysis are made of 20 sets of one-dimensional position-sensitive plastic scintillation counters with a size of 100 cm × 10 cm × 5 cm, and they cover the area of 100 × 100 cm. The last plane for detecting doubly scattered neutrons or recoiled protons is made of the two-dimensional position-sensitive liquid scintillation counter with a size of 100 cm × 100 cm × 10 cm. The effective analyzing powers Ay;eff and double scattering efficiencies ǫD.S. were measured by using the three kinds of polarized neutrons from the H(~ p, ~n)pp, Li(~ p, ~n)Be(g.s.), and C(~ p, ~n)N(g.s.) reactions at Tp = 198 MeV. The performance of NPOL3 defined as ǫD.S.(Ay;eff) 2 are similar to that of the Indiana Neutron POLarimeter (INPOL) by taking into account for the counter configuration difference between these two neutron polarimeters.