Figure3: (a) In order to pull the cold head unit out of the magnet, 4 hex screws (OUTER ONES)
should be removed as shown in the cartoon. The cold-head should be taken out very slowly (b). Before
disassembling the cold-head, the He-flux lines should be disconnected, and the excess gas should be vent using
appropriate couplings, one by one, first for the supply line and then the return line.
Once the cold-head is carefully removed from the magnet, it has to be kept in a holder/shield provided
by the Sumitomo and keep it safely. The old cold head should be sending back to Sumitomo.
Figure 4: (a) A top view of magnet (helium chamber) after removing the cold head (c) New replacement coldhead,
already cleaned by the Sumitomo. The coldhead can be taken out from the casing by unscrewing the 4 large hex-
screws (same screws are being used to attach to the magnet). When we request exchange of cold head in the
future, we will receive the same fully tested coldhead with attachments from Sumitomo. When it is taken out we
need to purge it with He-gas. Also the inner portion (a) of the magnet also should be purged for some time with
low pressure He-gas before assembling the cold-head to the magnet. (c) The refurbished cold-head sent by
Sumitomo will be filled with He-gas, therefore it has to be vent before start connecting to the magnet (Youngwoo
please confirm this step-I am confused why it was not directly connected, then we did not need to re-purge the gas
again? Confirm it with Roy, may be?).
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