sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

Hi,

In case it's not clear, after our testing (10 A) on Monday, Cryo needs time to re-generate liquid He.    This morning (around 8 am) Paul Orfin
had started cooling down again  and  we hope to reach suitable environment around 1 pm, then Carl can use his 75 A power supply to test the
superconducting bus  further.  

Today, Carl is better prepared.   On the other hand, today, because of only ~38 hours' regeneration ( my rough estimate ), it seems that we started
cooling down from roughly  ~50% storage in the Plant (Liquid He), instead of 70% storage.   Available time is more limited ...

Kin

On 01/22/2018 06:50 PM, Kin Yip wrote:

Hi,

For those who haven't seen the pictures, "Extension End2.jpg" shows you the two temperature sensors in the doghouse underneath the Valvebox.  The sensors are inside those white tapes
around the kapton.   These two sensors (TT1786/TT1787) somehow read ~25 K at lowest (though it was still dropping but slowly ........).  By comparision, TT1789 (Magnet End).jpg was the picture
for the temperature sensor placed in the doghouse at the Magnet end of the Extension.  These TT1788/1789 read 5/6 K or so.    Maybe, you could see a difference in the amount of Kapton
shielding.   This is the puzzle or issue that we have tried to resolve today.

Carl tried injecting  up to 10 A today by using a small power supply (which can give ~10 A or so) and he didn't really see any voltage increase across the voltage tap that he's measuring.  
But there was some mysterious temperature rise in the sensor HT04 (a bit closer to the current leads) which may or may not be due to our Carl's current.   It didn't drop for a long time
(~15 minutes) even after we stopped the current but it suddenly jumped back down, like off a cliff. 

Anyway, we tried to find another power supply which could give higher current.  We found one with 75 A (that ChaoFeng Mi told us) but we couldn't find any cables (208 V) for it.
So, we called it a night.  Since we used a lot of He inventory, we couldn't run tomorrow.  So, we hope to run this test again Wed. or Thur. depending on the Cryo situation.

In any case, we are running higher and higher current into the Magnet :-)     I just went to check the magnetic field as the Magnet did see current.  So, I attach the Magnetic field plot
this afternoon.  You can see the peak of ~28 G at 10 A and then ~23 G at 8 A where Carl stayed for a long time.   The Magnet and the probes are working :-)

Hopefully, this temperature sensor issue could be resolved when we go up to 75 A.  After that, Carl told me that we'll go back really to "our" (5000 A) power supply. 

I chatted with Joshi this afternoon, he also encouraged us to go to hundred(s) of A to see :-)

Kin

-------- Forwarded Message -------- Subject: Fw: temperature sensors outside kapton --- the reason for reading high temperature ?? Date: Mon, 22 Jan 2018 12:16:10 -0500 From: Yip, Kin <kinyip AT bnl.gov> To: Anerella, Michael D <mda AT bnl.gov>

Kin

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

From: Kin Yip

Date: Thu, Jan 18, 2018 6:03 PM

To: Than, Yatming (Roberto);Plate, Stephen;Anerella, Michael D;

Cc: Tallerico, Thomas N;Meier, Richard;

Subject:temperature sensors outside kapton --- the reason for reading high temperature ??

Hi Mike and Steve,

[ I have repeated myself to Roberto/Tom/Richard and Steve. ]

In pictures IMG*.JPG, you can see "X" which were the positions where Carl et. al. had marked the locations where the temperature sensors should be placed at the Extension End (underneath the ValveBox). 
In reality, it's slightly off (to the other side) and you can see from the pictures Extension End*.jpg  --- sensors underneath underneath those white tapes.

Somehow these two temperature sensorss   read >~ 25 K even after a long time of cooling.    Roberto seems to think that it's because the temperature sensors are mounted outside the Kapton
insulation.  Agreed ?


By comparison, the other two sensors placed at the Magnet Ends can be viewed in "TT1789 (Magnet End).jpg" at bldg. 902  before being taken to bldg. 912. 

After installation, you may find them in :

https://collab.external.bnl.gov/sites/sPHENIX-Magnet/Pictures/High%20Field%20Test/Another%20side%20of%20the%20junction%20(Magnet-Extension).jpg

also on the kapton with black cables/wires attached.   Somehow these pair of sensors at the "flex" read 5/6 K .  Because the kapton shielding is less thick ???

Kin

On 01/18/2018 03:56 PM, Than, Yatming (Roberto) wrote:

 

Kin,

Do we have pictures of to show where the temperature sensors were installed for the splice joints.

Steve is looking into why we are reading 25K and the 2^nd joint.

 

Roberto

 

 

 

 

 

 

 

 

 

 

Roberto Than

Cryogenic Systems, Collider-Accelerator Department
Brookhaven National Laboratory
Building 1005S, MS 1005S, Room 212
Upton, NY 11973-5000
Telephone: (631) 344-7165
Cell 631-487-6842 
E-mail: ythan AT bnl.gov

 

From: Plate, Stephen
Sent: Thursday, January 18, 2018 3:22 PM
To: Than, Yatming (Roberto) <ythan AT bnl.gov>
Subject: sPHENIX Valve Box Extension
Importance: High

 

Hi, Roberto.  Mike Anerella informed me that the sPHENIX valve box lead extension is not functioning as expected.  Since I am available to investigate the issue, he has assigned to me the task of looking into why the leads in the connection box at the magnet end are warmer than they should be.

 

I have the Creo model of the extension assembly.  Can you provide me with a schematic or a sketch that shows me the placement of the thermometers on the buswork in the extension along, with their steady state reading?  Of course I’m assume here that you have been able to reach steady state.  Thanks.

 

Stephen R. Plate

Brookhaven National Laboratory

P.O. Box 5000

Bldg. 902A

17 Cornell Avenue

Upton, NY  11973

plate AT bnl.gov

631-344-4475