Magnet Reservoir

The LHe reservoir for the target's superconducting magnet is outfitted with LHe level probe LL91111, three 5 psiG relief (or quench) valves directly on top of the cryostat, a 4 psiG relief valve on the gas panel, and a 0-2000 mbar strain gauge PI91121 mounted on the gas panel. Boil-off from the magnet is measured by FI91115, also on the gas panel.

Under normal conditions, the boil-off is passed through a 1'' solenoid valve, SV91115A and is recovered (``recycled'') at ESR via the warm return line. The option of venting the magnet boil-off directly to the Hall exists via solenoid SV91115. These solenoids are wired such that opening one valve automatically closes the other. In this way, it is guaranteed that one valve is always open. The relay for vent solenoid SV91115 is tied to PI911211 so that the valve will automatically open whenever the pressure exceeds 1300 mbar. The valve should be closed by the target operator once the pressure drops below 1300 mbar.