sPHENIX discussion of the superconducting solenoid

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

Dear Adrian,

As we chatted, can you please put a sign like the photo I attach on the door for 1008B mezzanine ?  That sign in the photo was placed on the 1st floor of 1008B.

Please change "abort RHIC beam" to "trip sPHENIX Magnet" ;

and change "C-AD Vacuum Ext. 4612" to "C-A Support Ext. 2024".

Kin

-------- Original message --------

From: "Yip, Kin" <kinyip AT bnl.gov>

Date: 11/7/22 3:42 PM (GMT-05:00)

To: sphenix-magnet-l AT lists.bnl.gov

Cc: "Michnoff, Robert J" <michnoff AT bnl.gov>, "Albanese, Marianna" <malbanese AT bnl.gov>, "Mannel, Eric" <mannel AT bnl.gov>

Subject: Mapping again ... 20 A power-supply current jump (walkie-talkie !) ... Pablo requests 1-2 days test after the mapping

Hi,

After the LOTO/pole-tip door business, we started ramping at 8:15 am and we reached the top about 10:03 am.   The mapper started taking data at 10:09 am for the 44-hour run.    I put quite some information in our C-AD Elog ( https://elog.pbn.bnl.gov:8181/elogs/entryList.jsp?DATABY=shift&ELOG=sPhenix&PAGE=1&DIR=backward&AUTO=yes&MODE=ALL#1669362 ) --- inside C-AD firewall of course.

There are typically fluctuations in the currents, slightly more for the power-supply current than the magnet current.

But around 1:39 pm, I saw a ~20 A jump in the power-supply current and luckily it went away quickly (a few seconds) and only caused ~1 A jump

in magnet current, and no noticeable damage was done.   ( You may remember that we saw a rise of ~400 A for 85 s on Oct. 26 which eventually tripped the Power-Supply and therefore Magnet due to crowbar over-temperature. )  I attach the plot for the current rises and the gas-cooled-leads (voltage taps) actually also saw the jump as well.

I emailed with Pablo/Carl.  A few minutes later when I called Pablo, we discussed and apparently at that time, a CAS person was using radio/walkie-talkie in 1008B mezzanine --- close to our Power Supply.  Pablo said that he'd seen this before and the strong RF signal can trigger disturbance like this.   I was told that we actually have a sign in 1008B (probably on 1^st floor) to tell people not to use radio.  ( I'm going to take a look later ... ) 

And by the way, for things like this (Pablo wants to see whether radio signal on 1^st floor would affect the Power Supply), Pablo requests a 1-2 day test after the mapping.   We can ramp down the Magnet to take out CERN equipment if necessary and ramp the magnet back up.  Pablo's test can be done easily as long as we do keep the Cryo at He temperature.  We have to remember not to warm up immediately after the mapping is done. 

John Haggerty is taking over after 4 pm ... Eric Mannel will do the "00:00 to 08:00" shift.

Kin

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