A Circulating Noble Gas Polarizer for a 129Xe EDM Measurement

A new experiment is being prepared at LANL to measure the electric dipole moment of 129Xe with 3He comagnetometry using SQUID detection. The experiment is carried out by precisely measuring the Larmor precession frequency of polarized 129Xe and 3He atoms with applied electric and magnetic fields. The desired improvement in statistical sensitivity over previous measurements will require the collection of spin precession data over the course of weeks or months. To this end, an automated system for the delivery of a polarized 3He - 129Xe mixture has been developed at the University of Michigan. The noble gases are polarized via spin-exchange with Rb vapor using a grating-tuned diode bar in a temperature-controlled cell. A single diaphragm pump creates pressure gradients that are used to transport polarized gas into a measurement cell, and gas is run through a purifier for reuse in subsequent measurements. In preparation for use for upcoming data collection runs, the system's ability to polarize and transport gas is being tested at Michigan by transporting gas into a small magnetic shield and detecting Free Induction Decay signals using an optically-pumped magnetometer.