Measurement of the absolute neutron beam polarization from a supermirror polarizer and the absolute efficiency of a neutron spin rotator for the NPDGamma experiment using a polarized $^{3}$He neutron spin-filter
| Autor: | S. Balascuta, P. R. Huffman, P. E. Mueller, M.M. Musgrave, D. Blyth, W. M. Snow, V. Cianciolo, Nadia Fomin, Geoffrey Greene, J. D. Bowman, Christopher Crawford, C. Hayes, M. McCrea, E. Tang, J. Hamblen, L. Barrón-Palos, K. Craycraft, Zhaowen Tang, Kyle B. Grammer, S. Kucuker, W. S. Wilburn, Chenyang Jiang, Xin Tong, S. Baeßler, R. C. Gillis, Seppo Penttila, Timothy Chupp, Michael Gericke, J. Fry |
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| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Nuclear and High Energy Physics
Physics - Instrumentation and Detectors Astrophysics::High Energy Astrophysical Phenomena Nuclear Theory FOS: Physical sciences 01 natural sciences law.invention Nuclear physics law 0103 physical sciences Neutron Nuclear Experiment (nucl-ex) 010306 general physics Nuclear Experiment Instrumentation Physics 010308 nuclear & particles physics Instrumentation and Detectors (physics.ins-det) Polarizer Neutron radiation 3. Good health Neutron capture Beamline Neutron source Physics::Accelerator Physics Spallation Neutron Source Beam (structure) |
| Popis: | Accurately measuring the neutron beam polarization of a high flux, large area neutron beam is necessary for many neutron physics experiments. The Fundamental Neutron Physics Beamline (FnPB) at the Spallation Neutron Source (SNS) is a pulsed neutron beam that was polarized with a supermirror polarizer for the NPDGamma experiment. The polarized neutron beam had a flux of $\sim10^9$ neutrons per second per cm$^2$ and a cross sectional area of 10$\times$12~cm$^2$. The polarization of this neutron beam and the efficiency of a RF neutron spin rotator installed downstream on this beam were measured by neutron transmission through a polarized $^{3}$He neutron spin-filter. The pulsed nature of the SNS enabled us to employ an absolute measurement technique for both quantities which does not depend on accurate knowledge of the phase space of the neutron beam or the $^{3}$He polarization in the spin filter and is therefore of interest for any experiments on slow neutron beams from pulsed neutron sources which require knowledge of the absolute value of the neutron polarization. The polarization and spin-reversal efficiency measured in this work were done for the NPDGamma experiment, which measures the parity violating $\gamma$-ray angular distribution asymmetry with respect to the neutron spin direction in the capture of polarized neutrons on protons. The experimental technique, results, systematic effects, and applications to neutron capture targets are discussed. Comment: 13 pages, 14 figures, 2 tables |
| Databáze: | OpenAIRE |
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