750 Helium Fill

Order 250 liter Helium for ~ 1 week delivery after we hit 60% on meter.

Fill magnet completely with N2(li) before doing a fill. Ice jams form inside ports if not done.

We need to slowly let the Helium overhead pressure drop to ~980 mBar before opening magnet. on top of console is a meter which reads this pressure ("atmospheric pressure device"). Overhead pressure is usually 1.029 bar (1.0155 atm). To drop slowly:


• turn off atmospheric pressure device 12 hours before a fill (ie night before). the helium gas should bleed out slowly down (~4 mbar/hr) to ~1atm (980 mbar) now.
• remove helium port stopper slowly and completely and put back top part as a plug.
• remove check valve completely and stopper with kim wipes
• cool down transfer line until you see the flame as usual and insert line
• vent dewar and try and insert line with out o-ring at adapter point. i don't think they are necessary..
• ramp pressure up to 2psi and let fill. takes appx 1.25 hrs from 58%
• The next day come in and clear the inside of the N2 ports from ice build-up. This is a problem on this magnet.