sPHENIX discussion of the superconducting solenoid

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

Meeting page:  https://indico.bnl.gov/conferenceDisplay.py?confId=4307

 

1.      When the meeting “formally” started, I gave a presentation of my analysis of the strain gauges.  There, I described our two modes of detection (as we needed to deal with a short circuit
problem).  I used the examples of TS21 and TS08.   

By measuring the differences of strain gauge readings at 0 A and at higher current, the two modes seemed to be consistent (when I checked).   And the stress derived from the strain seems to be consistent with the force that is proportional to the square of the current.    In the two strain gauges (TS21 and TS08), the steps/shape in the strain actually reproduces the steps/shape of the current rise.   This is the first time that I can make good sense of the strain gauge.

2.      We’ll keep vacuuming until the magnet returns to room temperature ( in a month or two ).   After that, it’s suggested that we put in nitrogen to prevent dirt etc.

3.      After the warm-up, we also want to remove the top steel and loosen the pre-loaded jack.

4.    I showed the P6 schedule and according to the schedule, we should be doing “Preliminary Engineering Transport Tooling and Misc. Parts” from Feb. 1 until Apr. 12, 2018. 
Mike Anerella said that the work needed is actually easy.  Jim said that we should postpone this job after we figure out what/how to repair/fix.

5.      Then, we went to Carl Schultheiss’ slides. 
--- He mentioned that he should fix the gain by changing some resistors/capacitors. 
--- He also suggested that we should buy another A-to-D board and send the Quench Signal to all three boards to use for time alignment.
--- Then, he had the recommendation to replace the PXIe hardware as it wasn’t robust/fast enough to do some calculation that he wants.  Another point is that after a quench,
the data file (for quench) couldn’t be sent automatically to the C-AD Control System and one has to log into the quench detector and move them from the real-time hard drive to the Windows hard drive before the data can be shipped to someone.  This is not acceptable for operations.

--- We talk about whether  and how to fix VT10 and VT11 voltage taps.   There is a general sense that though we probably don’t want to open the Cryostat, we can open the Doghouses (on both sides of the Extension) to try to see whether we can locate the problems for the VT10/VT11.  There is a chance that we may not be able to fix anything.
--- We have also discussed the fact that we have got one MT thermo-sensor that is working (MT01).   It’ll be great if we can fix other ones but they’re all hidden inside the Cryostat. Brian van Kuik talked about sending a “snake” type of instrument to insert a thermo-sensor.   But it seems impossible to do so.

 

6.      We probably won’t have biweekly meeting from now on.  Jim Mills said that we should write a report for the High-Field Test.

 

 

 

Kin