Performance of the neutron polarimeter NPOL3 for high resolution measurements

Abstract We describe the neutron polarimeter NPOL3 for the measurement of polarization transfer observables D ij with a typical high resolution of ∼ 300 keV at T n ≃ 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 2 . 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 A y ; eff and double scattering efficiencies e D . S . were measured by using the three kinds of polarized neutrons from the 2 H ( p ⇒ , n ⇒ ) pp , 6 Li ( p ⇒ , n ⇒ ) 6 Be ( g . s . ) , and 12 C ( p ⇒ , n ⇒ ) 12 N ( g . s . ) reactions at T p = 198 MeV . The performance of NPOL3 defined as e D . S . ( A y ; eff ) 2 are similar to that of the Indiana Neutron POLarimeter by taking into account for the counter configuration difference between these two neutron polarimeters.