Design of the polarized 3He filling station. The four major subsystems are gas supply system, gas transfer system (the syringe), a SEOP pumping system, and the wideangle analyzer cell system.
The schematic for the gas filling system.
The schematics of the gas transfer system. The 8 in. air cylinder outer casing is not shown for indication purpose.
The schematics of the valve, bottom piece. Top piece of the aluminum pancake is indicated in Figure 3 , part number 17.
Schematics of the optical pumping cell (OPC) in different stages. Top left: before baking; top right: after baking; bottom: after optical pumping, capillary blockage test.
Top: the wide-angle analyzer cell (WAC), design (unit in mm) and picture. Bottom: the Helmholtz-like coil system which is used to provide uniform magnetic field for the WAC.
Top: the filling station cart with the solenoid removed. Upper left box: cell bake-out oven. Upper center box: piston assembly. Upper right box: servo drive and stiffening enclosure. Lower left box: 3He and N2 gas supply bottles. Lower center box: NuPure Getters and gas plumbing. Lower right box: recycle tank.
Free induction decay signals (mv) vs. time (h). Left: the saturated 3He polarization slowly decayed with time; right: after we drove Rb to the capillary tubing to isolate the OPC from the valve, the 3He polarization stayed constant for more than a week, indicating a small gas leakage from the valve.
The optical pumping cell (OPC) lifetime measurement, the signal decays exponentially with a time constant called lifetime. Left: the OPC lifetime measurement, the fit gives 8.7 ± 0.4 h of lifetime; right: the OPC is blocked from capillary using Rb, the fit gives 10.5 ± 1.6 h of lifetime.
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