Nuclear spin-polarized 3He efficiently polarizes neutrons over a wide energy range including cold, thermal and hot neutron spectra by means of its strongly spin-dependent absorption of neutrons. At Forschungszentrum Jülich we are studying the optical polarization of 3He by two methods, metastable exchange and spin-exchange, in order to optimize the neutron polarization at various spectrometers of the FRJ-2 reactor. For the spin-exchange method we designed an open, refillable cell system. In contrast to the conventional sealed cells adopted at many other laboratories, we will be able to vary many crucial parameters in the 3He cell, such as gas ratios of 3He and N2, total gas pressure, and temperature while always working in the same experimental environment of a single cell. Laser polarized Rb vapor is used to polarize 3He through the spin-exchange interaction, and NMR is employed to determine the polarization of the 3He after calibration with a proton (water) NMR signal. In this paper we will report the 3He polarization and relaxation rate, T 1, observed for various gas conditions.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Electrical and Electronic Engineering