A High-Pressure ³He Neutron Spin Filter--Science Research Laboratory, Inc., 15 Ward Street, Somerville, MA 02143-4228; 617-547-1122
Dr. Jonathan Richardson, Principal Investigator
Dr. Jonah Jacob, Business Official
DOE Grant No. DE-FG02-99ER82878
Amount: $749,942

Polarized neutron scattering (including small angle reflectometry and refraction) has been demonstrated to be an invaluable tool in the characterization of magnetic and non-magnetic materials. Current neutron polarization methods are limited to well-collimated, low energy beams, precluding their use as spin analyzers in most cases. To overcome these limits, this project will develop a reliable apparatus, utilizing a dense polarized gaseous ³ He spin filter, for polarizing ³He with adequate throughput to supply one or more neutron scattering facilities. The system will be able to produce 1 liter-atmosphere of ³He at >50% in 1 hour. The application of this system to neutron spin analysis also will be demonstrated. The Phase I project improved an existing polarization apparatus, leading to participation in a polarized neutron reflectometry experiment at the Argonne National Laboratory Intense Pulsed Neutron Source (IPNS). Also, a novel high-power laser was demonstrated and will be used in the improved Phase II polarizer. The Phase II project will address the current deficiencies in the design of the polarizer, develop a next-generation laser, and develop polarizer cells that should offer simpler construction and improved ³He polarization lifetime. Further polarized-neutron measurements are planned at the IPNS.

Commercial Applications and Other Benefits as described by the awardee: There are over nine neutron scattering centers in the US and Canada and over 22 abroad. Currently, plans exist to build a new $1.36B scattering facility in the U.S. called the Spallation Neutron Source (SNS). The technology developed in this project can supply polarization equipment to both existing and future facilities. In addition, polarized ³He can be used for medical imaging and characterization of material microstructure.