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Filling with commercial dewars or not: The main helium gas intake manifold is designed so that it is relatively easy to connect high purity commercial gas bottles, compress it and store it. If we fill the magnet and have enough to store for at least two other fills then we can prepare to run a very minimalist target system to have some beam on target. I point this out incase it becomes relevant for us or either agency down the road. It's better if we can figure out a FNAL protocol for storing additional LHe in the Hall or filling with LHe from a delivery. The QT system can produce 200 L per day but our transfer is expected to be about 60% efficient. The magnet holds 135 L but depending on the starting temperature of the coils the magnet fill can require significantly more than 135 L. From about 80 K the fill would require about 300 800 L. If it's kept at about 4K then you only need about 185 360 L to fill. Right now we can only store a maximum of 500 L of liquid. It would be possible to run a minimal target system (magnet and fridge) for a couple of days with even fewer electronics needed than what is listed in the critical path electronics. To polarize we need only a temporary microwave setup and polarization measurements. To measure the polarization we need the UVA NMR running in the Hall storing data to the NMR local machine. For the minimal polarized target system with no running roots and no continuous running QT system one could get about 20% proton polarization achievable at any time of the year even if other parts of the system are not yet leak-tight and/or ready to run. This is also a reasonable mode to begin commissioning the target magnet.
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