Metastability-exchange optical pumping of {sup 3}He for neutron polarizers
Research is underway at NIST and IU to develop neutron polarizers that are based on polarized {sup 3}He. Such polarizers rely on the strong spin dependence of the cross section for neutron capture by polarized {sup 3}He. Two methods can produce the high density of polarized {sup 3}He gas (10{sup 19}-10{sup 20} cm{sup -3}) required for an effective neutron polarizer: spin-exchange optical pumping, which is performed directly at high pressure (1-10 bar), and metastability-exchange optical pumping, in which the gas is polarized at low pressure (1 mbar) and then compressed. While we are pursuing both methods, progress in the metastable method will be discussed. The features of the metastable method are the high rate at which the gas can be polarized and the inherent separation of the optical pumping and target cells. In a landmark achievement, researchers at the Univ. of Mainz have developed a piston compressor that can fill a 130 cm{sup 3} cell to a pressure of 7 bar of 45% polarized {sup 3} He gas in 2 hours. We plan to develop a compressor and test it at the NIST Cold Neutron Research Facility. We have constructed a metastable-pumping apparatus at NIST and have obtained 76% polarization with a pumping rate of 1.2 x 10{sup 18} atoms/sec in a 0.4 mbar, 270 cm{sup 3} cell.
- OSTI ID:
- 255540
- Report Number(s):
- CONF-9510116-; ISSN 0003-0503; TRN: 96:015848
- Journal Information:
- Bulletin of the American Physical Society, Vol. 40, Issue 10; Conference: Fall meeting of the Division of Nuclear Physics of the American Physical Society, Bloomington, IN (United States), 25-28 Oct 1995; Other Information: PBD: Oct 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
Polarized {sup 3}He gas compression system using metastability-exchange optical pumping
Compressing Spin-Polarized 3He With a Modified Diaphragm Pump