sPHENIX discussion of the superconducting solenoid

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

 

Powerpoint: https://indico.bnl.gov/conferenceDisplay.py?confId=3943 :

 

 

1.      I first mentioned that there will be an External Review for the Cryo System for the sPHENIX Magnet in IR8 on Jan. 12, 2018, with

reviewers: Wes Craddock, Pasquale Fabbriocate, Yuenian Huang, George Ganetis.  The review will start at 11 am (East Time).

The charge of the review is :
To determine whether the cryogenic system design seem technically sound, in regard to capacity,  operational capability and flexibility, cryogenic safety, cooldown control and sufficiency of cryogenic interlock signals (for magnet protection).  

We'll be using the following bluejeans connection that we've had for the sPHENIX Biweekly meetings (but we’ve rarely used) :
https://bluejeans.com/555932410  for video-conferencing. 

2.      Jon Hock and the technician (Ed Dabrowski) did pre-loading for the Cryostat this morning/early afternoon (for the 3^rd time and also the last time).   Jon told me that 

it’s easy as they had the right equipment from the survey group.  Survey group will go there measuring for the last time tomorrow morning.  Ed will also do some
cleaning/vacuuming.

 

3.      Frank Toldo reconnected a strain gauge “connector” that came off ( as Jon noticed).  He and Carter Biggs will install the magnetic probes tomorrow morning hopefully.

 

4.      Jesse Fite will take a final look before we put the end-walls.   Hopefully, they can start installing the end-walls tomorrow afternoon.

 

5.      Paul Giannotti told us that basically he’s waiting for Frank Toldo to be free to install the connections for strain gauges and linear pots (including the new ones from Jon Hock).

 

6.      P. Rosas’ technicians (such J. Meier) are doing high-pot and power supply test in 912.  

 

7.      I mentioned that the PLL (phase-lock-loop) problem that Carl/Zeynep saw disappeared after some rewiring.  Fred Orsatti (Carl technician) has been working on the voltage connections from the lower platform to the quench-detection rack.

 

8.      Paul Orfin told us that after one night of purification, the purity/dirt level is 30-38 ppm (due to nitrogen, water …).   So, he’d like to continue to purify for another day.  He hopes that at least it’d go below 15 ppm.   I or we learnt that there was a ~mile long pipe between 912 and RHIC which they have been using to send He to be purify.

 

So, the plan is that they may start the Plant Thursday, ie. cool down the Plant/dewar to ~80K and then start to build inventory of He.  Hopefully, by Monday, they’ll have enough He to start cooling down the Magnet, assuming the end-walls are all installed by then.

There was a discussion whether we could start cooling down without the end-walls.  But doing so will require talking with the safety people which may involve some calculation and writing document, which will take time.  It’s easier to just close up the end-walls as soon as possible.

 

9.      Joe Muratore in the meeting and then now Carl Schultheiss (after the meeting) both reminded me/us that we have to do high-pot test on the Magnet after the cool-down.