3He Polarization Techniques for the European Spallation Source
Neutron polarization analysis is a key technique for modern neutron scattering research centers. 3He polarization for neutron polarization analysis will be applied at the European Spallation Source (ESS) to be constructed in Lund.
In-situ spin-exchange optical pumping system will be used for polarization analysis of scattered neutron beams at the JCNS, these techniques will later be applied for neutron instrumentation at the ESS when completed (projected for 2019). Devices are based on optical pumping, one of the classic approaches of atomic physics which is also applied in such areas as frequency standards/clocks, magnetometers, and fundamental studies.
Instrumentation to be developed and improved includes both compact on-beam systems, and a large scale high throughput system for production of polarized gas. Further work will be done to apply the systems to neutron scattering studies.
On-line compact analyzer system is currently being developed and prototyped for SANS as shown in fig.1. The system will use an 18 cm long mu-metal end–capped and shielded solenoid. The system will have a small entrance aperture and large exit aperture in the end caps for the scattered neutron beam. This design will allow the sample to be placed within 2-3 cm of the 3He cell while using standard sample environment.