sPHENIX discussion of the superconducting solenoid

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

    Powerpoint/Agenda (https://indico.bnl.gov/conferenceDisplay.py?confId=4065):

 

 

1.      It was intended to switch to the Plant (He) to cool the Magnet from 90-100 K to ~4 K on Jan. 2, 2018.  

But unfortunately, very early last Friday morning (Dec. 29), ODH alarm going off triggered the “cooling” fan in the 912 compressor room while the “heating” in the heat exchanger didn’t work
Þ vacuum skid cracked Þ no water return eventually causing the Plant to stop
Þ Cryo deteremined that the Plant was plugged Þ warmed up the Plant over the weekend.

           Fans (heat exchanger) have been fixed.  The ODH sensor in the compressor was replaced (Dec. 29).  They will try to replace the ones in Bldg. 912 while we’re running Cryo.

 

2.      Yesterday evening, frozen moisture/water closed an ODH valve and that closed LN2 supply.  Temperature rose and we saw more at the splice joint (> 115K) than for the coil (105 K).  Paul Orfin tried to instruct CAS to do some diagnosis but they really found and fixed the problem when the Cryo experts came in this morning.  LN2 was back later this morning.  Paul told us that “We are looking to replace the control air line with a larger diameter to limit any internal frost build up.”

3.      As of now, the Cryo group has restarted the Plant … Paul estimated that by late Friday, they can in principle to try to get to 4K.   But obviously, that’s not a time.
So, we’ll try on Monday (Jan. 8, 2018) to go to 4K.

4.      Carl Schultheiss wants to use the short-circuit to test some ramp up again on Friday.  And then we hopefully do hipot on Monday (Jan. 8).

5.      I was hoping that Frank Toldo and Mike Lenz can make the box flexible (that we may connect/disconnect).   But apparently, they can’t.  They will install the box
only after the hipot test is done.   So, we need to wait for this box to be installed.  After that, we can get all the signatures to start the High-Field Test.

6.      We also have the Cryo Review next Friday (Jan. 12, starting 11 am).   People asked whether this may interfere but Roberto said that it’s OK as it’s just a couple hours.