sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

Hi,

As I said in my summary email that the short-circuit test already went to 4700 successfully.  Pablo and his technician
keep the current in "short-circuit" for more than 2 hours ...  I went to 912 again and Pablo told me that he wanted to
see how high the temperature on the 535 MCM cables would go.  This is something that Dave Phillips has worried about.

Apparently, the temperature of the cables went only as high as 133 F (or so), as Jimmy Meier told me.  Before I left 912 <~ 5 pm,
the temperature seems stabilizing.   The MCM cables are rated at 110 C or 230 F and so it's fine.   Pablo said that they'd
stay for another half an hour and would call it a day.

Pablo made a comment that PK Feng's wooden blocks (to separate the MCM cables, which cost several thousand dollars) definitely
help.   They saw significant temperature drop when cables are separated by the wooden blocks.  And wooden blocks made sure
that the cables are separated.

Kin

-------- Forwarded Message -------- Subject: [Sphenix-magnet-l] Brief Summary of Today's sPHENIX Magnet biweekly meeting (Dec. 20, 2017) at 1:30 pm at the 902A conf. room Date: Wed, 20 Dec 2017 21:38:04 +0000 From: Yip, Kin <kinyip AT bnl.gov> To: sphenix-magnet-l AT lists.bnl.gov <sphenix-magnet-l AT lists.bnl.gov>

Powerpoint : https://indico.bnl.gov/conferenceDisplay.py?confId=3994

 

1.      We first discussed about the cool-down.  It really started last Friday (Dec. 15) as there was some flow issue.  It’s not meter,
not wiring nor software.   Brian van Kuik explained to us that it’s some noise issue such that the valve 3613 (for example) may shut off when there is spurious
signal.  For now, their solution is to only close it by 50% (half-closed).  They are, eg., trying to stretch a coiled cable (near power supply and the Cryo rack)
to get rid of an antenna/inductor effect … Tom Tallerico said that there are commercial kits that they can buy to overcome this if it’s really necessary.

 

2. Strain Gauge/linear-pot connections are still not completed.  They found a mistake and also the short-circuit test and Pablo’s other test works have prevented
    them from doing the works.   I have asked Ralph Schoenfeld and he assigned Peter Zimmerman to help us finish the cabling Thursday and Friday.

---  Richard Meier has helped us plug in a deformed J5 plug to the Valvebox.

3.  Pablo, Carl, Zeynep with technicians are doing the short circuit test.  When I was there >an hour ago, they have gone to ~4700 A and Pablo would like to stay there for a    couple hours.  They’d want to do it again.

      4.  Roberto’s optimistic estimate (from his email … as he was not present in the meeting) is that they can change to He cooling from the Plant when they reached  ~144K and
            they may reach 4.x K by Dec. 29.

     5.  However, a few persons’ vacation schedules after this week, may slow us down from proceeding in the quickest :

           ---- Pablo will be off for 2 weeks and will be back on Jan. 8, 2018.

          ---- Carl will be back ~Jan. 2, 2018.

          ---- Mike Lenz will be back Jan. 2, 2018.

     6.  If the Magnet is really cold ~ Dec. 29, 2017, try hipot-testing the Magnet on Dec. 29  (or Jan. 2, 2018 otherwise).

         Only then, Mike Lenz can install the box around the current leads afterwards, which may take a couple days.

     7. Then, Carl may work on compensating for L & R in the power supply in Pablo’s absence.  Whether we may wait for Pablo’s return to really
         start ramping up the power supply with magnet, I leave it up to Carl.  Jon Sandberg et. al. have thought that we should wait for Pablo for its
         power supply start with the Magnet.

 

     8.  People discussed and I had promised to send a list of works that need to be done for the High-Field Test.    I had sent the list before I send this summary.