2019 Workshop on Polarized Sources, Targets, and Polarimetry

NOPTREX: Polarized 3He Neutron Spin Filter and Polarized Xenon Pseudomagnetic Precession

26 Sept 2019, 10:00

20m

Downtown Holiday Inn

Polarized Neutrons Polarized Neutrons

Speaker

Hao Lu (Indiana University Bloomington)

Description

The Neutron OPtics Time Reversal Experiment (NOPTREX) collaboration is working towards a sensitive search for time reversal violation in polarized neutron transmission through polarized heavy nuclei. The experiment requires an intense, stable polarized neutron beam at the resonance energies of interest near 1 eV. We have recently constructed a ${}^3$He neutron spin filter at Indiana University which makes use of the very large spin dependent neutron absorption cross-section of ${}^3$He to polarize neutrons. We polarize ${}^3$He gas using spin-exchange optical pumping (SEOP). We have combined our laser optics and oven with a $\mu$-metal shielded solenoid and a ${}^3$He gas cell from ORNL to realize our polarizer. We also discuss a planned experiment to measure neutron pseudomagnetic precession in polarized xenon gas. ${}^{131}$Xe is one of the nuclei on interest for the NOPTREX test, and this measurement will help us determine a significant systematic error related to spin dependent components in polarized neutron-nucleus transmission and also measure the spin-dependent scattering amplitudes of both ${}^{129}$Xe and ${}^{131}$Xe for the first time. This experiment will use an Neutron Spin Echo spectrometer to measure pseudomagnetic precession and an existing SEOP system to polarize both ${}^{129}$Xe and ${}^{131}$Xe.

Presentation materials

PSTP2019HaoLu.pdf