A liquid helium target system for a measurement of parity violation in neutron spin rotation

Published

October 15, 2010

Author(s)

Christopher D. Bass, Tiffany D. Bass, B R. Heckel, C. R. Huffer, Paul R. Huffman, D Luo, D M. Markoff, A M. Micherdzinska, William M. Snow, H E. Swanson, S. C. Walbridge

Abstract

A liquid helium target system was designed and built to perform a precision measurement of the parity-violating neutron spin rotation in helium due to nucleon-nucleon weak interaction. The measurement employed an orthogonally-crossed neutron polarizer/analyzer pair surrounding the liquid helium target system. The expected parity-violating spin rotation of order $10^{-6}$ rad placed severe constraints on the target design. In particular, isolation of the parity-odd component of the spin rotation from a much larger background rotation caused by magnetic fields required a nonmagnetic cryostat and target system supported inside magnetic shielding, which allowed nonmagnetic motion of liquid helium between separated target chambers. This paper provides a detailed description of the design, function, and performance of the liquid helium target system.

Citation

Nuclear Instruments & Methods in Physics Research Section A-Accelerators Spectrometers Detectors and Associated Equipment

Pub Type

Journals

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Keywords

cryogenic targets, liquid helium, Parity-violation, neutron physics, nucleon-nucleon weak interaction, neutron optics, polarized neutrons

Citation

Bass, C. , Bass, T. , Heckel, B. , Huffer, C. , Huffman, P. , Luo, D. , Markoff, D. , Micherdzinska, A. , Snow, W. , Swanson, H. and Walbridge, S. (2010), A liquid helium target system for a measurement of parity violation in neutron spin rotation, Nuclear Instruments & Methods in Physics Research Section A-Accelerators Spectrometers Detectors and Associated Equipment, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=902210 (Accessed October 11, 2025)