sPHENIX discussion of the superconducting solenoid

["Yip, Kin" <kinyip AT bnl.gov>]

Hi,

 

Ø  ) I’m not sure the last 10 K or several K will need more time or less time ….

 

The last 10 K really seems to take more effort.  Around last midnight (between Wed. and Thur.), the coil temperatures went down to between

13-14 K (in absolute temperature scale).    Since those He gas itself is at this temperature, they couldn’t cool it further.   This morning,

soon after 7:30 am, they stop the He flow as they need to build liquid He inventory so that they can cool it to 4.5 K.    Right now, the LHe Storage

that I can check from “D405 ERL CryoFab LHe Storage” is ~52%.   Roberto would like it to be above 60% and this should be reached

sometime tomorrow.

 

Right now, the magnet coil temperatures have been rising ---- which gave us a chance to see how fast temperature increases as this is the way

how natural warm-up would happen to 10 K (for us to measure resistance at 10 K => RRR).   It seems to be faster than what Roberto had expected

… something like 1 K per hour or so.

 

So, after they build up the inventory and they’ll cool again  back down to ~10 K and switch to use the Liquid He to cool it towards ~4.5 K which

should hopefully be reached in the weekend.

 

 

Meanwhile,  we have done a few things today :

 

--- Achim Franz has moved his cart to the designated area;

--- Dave and I have just accompanied Jesse Fite and done the “Magnet Safety Review”.  We’ve cleaned up a few things (eg. moving carts with metals

     away from the magnet) and Jesse has placed a sticker on the Solenoid (see attached photo).   I’ve signed off this in the check-off list.

--- While Jesse was there, we have placed the 5 G chain around the magnet to show what the chain would be.  Jesse was happy about this.   I’ve

     asked Peter Cirnigliaro to sign off on this.

 

As a result, we’ve finished all the checkoff list(s) and safety procedure for the low-field test.

 

So, we (such as Sonny/Joe) will meet on Monday at 9: 30 am at the sPHENIX Magnet (Bldg. 912) to start doing the low-field test …..

 

Kin

 

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