Performance of the neutron polarimeter NPOL2 for (p→,n→) polarization transfer measurements

T. Wakasa, H. Sakai, H. Okamura, H. Otsu, S. Fujita, S. Ishida, N. Sakamoto, T. Uesaka, Y. Satou, T. Nonaka, T. Ohnishi, M. B. Greenfield, K. Hatanaka

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24 Citations (Scopus)


A high performance neutron polarimeter NPOL2 has been constructed to measure polarization transfer observables Dij for neutron kinetic energies of Tn = 150-400 MeV. The NPOL2 system consists of 6 planes of two-dimensional position-sensitive neutron detectors with a size of 1 × 1 × 0.1 m3. Neutron polarization is determined from the azimuthal distribution of the elastic n→ + p scattering in the scintillator material. The effective analyzing powers (Ayeff) of NPOL2 have been calibrated by using the polarized neutrons from the 0° 2H(p→,n→)pp reaction at Tp = 146, 228, 296, 346 and 392 MeV as well as by using the polarized neutrons from the 0° 6Li(p→,n→)6Be(g.s.) reaction at Tp = 228 MeV. The Ay;eff values of NPOL2 have reasonable values, typically 0.223 ± 0.012 and 0.132 ± 0.004 for (n→,n) and (n→,p) channels, respectively, at Tn = 291 MeV. The figure-of-merit value defined as εD.S.(Ay;eff)2 is over 4 × 10-4 for the wide neutron kinetic energy region of Tn = 200-400 MeV, where εD.S is the double scattering efficiency.

Original languageEnglish
Pages (from-to)355-372
Number of pages18
JournalNuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Issue number2-3
Publication statusPublished - 1998
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Instrumentation


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