An Experiment to Compress Polarized 3He Gas

Helium-3, polarized by optical pumping of the 23S1 metastable atoms at 1 Torr pressure, has been compressed to a pressure of 217 Torr and it has been verified that the gas remains polarized. 3He at 1 Torr was polarized and compressed into a storage bulb using a Toepler pump, and this was repeated with successive charges of 3He until the pressure in the storage bulb rose to 217 Torr after about 4 h of operation. Some of the gas was returned to the low pressure side of the equipment and its polarization was measured. The polarization attained before each charge was compressed was 0.04; the measured polarization of the returned gas was 0.03.