Metastability-exchange optical pumping of {sup 3}He for neutron polarizers

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Bulletin of the American Physical Society

OSTI ID:255540

Gentile, T R; Thompson, A K; Snow, W M

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--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 10 Vol. 40; ISSN 0003-0503; ISSN BAPSA6
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
66 PHYSICS
COLD NEUTRONS
HELIUM 3 TARGET
NEUTRON BEAMS
NEUTRON REACTIONS
NEUTRON SOURCES
OPTICAL PUMPING
POLARIZATION
POLARIZED TARGETS
SPIN EXCHANGE