sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

Powerpoint: https://indico.bnl.gov/conferenceDisplay.py?confId=4273

1. We discussed what to do next among the remaining items in the Run plan :

https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Shared%20Documents/High%20Field%20Test/2017-8-2%20sPHENIX%20Solenoid%20High%20Field%20Test%20Plan%20Summary%20v2b.docx


We have done most items and we can't really hold for 12 hours (due to cryo restriction).   We can't do power cycle as
this power supply doesn't allow us to ramp down in a controlled manner (as in ramping up at. 2A/s etc.).

Basically, we're going to try to  do

--- E2 (ramping at 2.5A/s, probably at 1000 A steps ... to the top)
--- E4 (ramping to 4830 A and hold for as long as Cryo allows)
--- F (we have done slow discharge already) : A fast discharge at ~4830 A

We've had quite a bit of discussion when to run next (considering next Monday is a Lab. holiday).   The conclusion is that we'll try to run again on Friday at 9 am. 


2.   We looked at the plot of the gas-cooled-lead (negative or positive) --- as in the powerpoint stored in indico and Carl is worried
that the lead flow may not be optimal.   Paul Orfin told us that there is a problem of pressure being too low that may prevent them from
going up to higher flow rate (though they can) with good stability.  For the 1008 sPHENIX configuration, we should purchase a better
thermal mass flow control to allow better control at lower pressure drop.

[  Paul said that the price difference may be just $3000 vs $4000 or something like that.  ]  People all agreed with that.