sPHENIX discussion of the superconducting solenoid

[Achim Franz <afranz AT bnl.gov>]

Kin,

the LakeShore probe did work, here is the plot, almost linear, but there are some fluctuations.

Achim

Attachment: Screenshot 2016-04-06 18.31.22.pdf
Description: Adobe PDF document

On Apr 06, 2016, at 17:27 , Kin Yip <kinyip AT bnl.gov> wrote:

It's a rather long meeting and I try to summarize as much as I can ... One thing that people had doubt in the meeting was about the freewheeling diode.  Pablo
just showed them to me.  In fact,  there are several freewheeling diodes (all in parallel) in this big Power Supply that we're going to use for the High-Field Test
=> Safe !


1.  Z.  Altinbas, C. Theisen, C. Schultheiss, Piyush and Sonny had a meeting yesterday (Apr. 5) to discuss about the power supply control, quench detector and
data logging for the High Field Test.    Bob Lambiase summarized that :
    (i) We'll use the PSI system to control the Power Supply.   There will be a pet page to control that.
    (ii) For the quench detection, we'll replicate Piyush system as in the Low Field Test.
   (iii) For the data logging, we haven't decided whether to make a system like Piyush's (using PIXIE) or use the VME system that C-AD has been using.

Zeynep and Piyush will make up a list and then we can see how much things cost.   The advantage to use a VME system that C-AD has been using is that
we may reuse it in the future sPHENIX experiment in 1008.   But it may take more effort and time --- which we may not have.   We'll look at the list
and costs and then decide.

For the strain gauge DAQ system, the simplest thing is to re-use it and I think this is the default.  People also say that we may want to improve it, which
also cost time/money.

2.  I showed a RRR measurement based on the jump of voltage seen in the evening on Mar. 22 and it's ~ 1600.

3. Bob Lambiase found a kink at the discharge curve for the outer coil after a shutoff/simulated-quench.   It's not a real quench as the voltage should go towards 0 instead of being
away from 0 that we've seen.  And we don't see such a kink for the total coil voltage.   It's kind of a mystery and probably due to instrumentation ...

4.  I showed the force calculation for the Full Field Test model with centered coil position and shifted coil position.  The forces are all small.    For "convenience" (that people like
Don Lynch prefers), we're building the Full Field Test system such that we're centered at the cryostat (which means that the coil is shifted by 2.85 cm or so).

5.  Carl Schultheiss is essentially replacing Bob Lambiase to help us for the power supply as Bob is involving in too many projects to help us.  And Zeynep Altinbas is
helping us for the control system (hardware and software) and she'll work with Piyush et. al. to make up the DAQ system for the high-field test.

6. Dave Phillips discussed his proposed position of the new Magnet position in Bldg. 912.    Though not final, Achim Franz thought that we might not need a hole in the middle of the
return yoke for his cables of the magnetic probes as they may go through the junction box.

Mike Anerella said that they'll help disconnect and connect the junction-box/extension for the High Field Test.  For disconnection, Dave was talking about in a month's time and Mike
thinks that that timeline is probably OK for Ray Ceruti and his group.


7.  Roberto discussed installing valves in the summer which can deal with higher pressure so that during cool-down, it wouldn't draw He from the He inventory.
 He also discussed the possibility of using a negative/lower pressure trick to increase his He capacity to improve the cool-down rate.

There is a problem of the sub-cooler being taken away for the 2 o'clock system.

8.  Jim Mills talked about the schedule.  It seems that we can finish the power supply/control/DAQ work or the Cryo work by the Dec. 15 deadline.   Dave Phillips' return yoke
installation is the limiting factor in our schedule.   Dave doesn't think Dec. 15 is very likely.

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