sPHENIX discussion of the superconducting solenoid

["Than, Yatming (Roberto)" <ythan AT bnl.gov>]

Basically:
Next Tuesday: 8 days, 182 hours of cooling at 0.6K/hr, 144K return with 110K supply which bottoms out from our LN2 cooler.
We will attempt to switch and see how the flow resistance is and try to supply 5K helium from the plant liquid helium storage dewar and mix with warm gas to get a colder supply.
We will try and see how everything works and get it to 4.5K on Friday. Maybe we try a cold high pot test Friday??
Roberto

---

From: sPHENIX-magnet-l [sphenix-magnet-l-bounces AT lists.bnl.gov] on behalf of EdwardOBrien [eobrien AT bnl.gov]
Sent: Monday, December 18, 2017 5:56 PM
To: Yip, Kin; sphenix-magnet-l AT lists.bnl.gov
Subject: Re: [Sphenix-magnet-l] ~255-260 K

    Hi Kin,
     Thanks for the explanation.

    Ed

On 12/18/2017 5:53 PM, Yip, Kin wrote:

Hi,

 

Before last Fri., Roberto thought that we could use a new scheme, ie. the Plant (He) to cool directly.  But when they tried to do it last Fri., they realized that now since we didn’t have sub-cooler, this “new” wouldn’t provide

enough “pressure” (??).   So, they had to go back to use the Nitrogen cool-down mode, just like last time.

 

The rate would be like this until ~100 K or so and then they could use the He to cool which will go quickly

to 4.x K  (like in 3 days last time).

 

Say, now, it’s 260 K and it’s ~0.6K per hour.  It’d take 11.11 days to go to ~100 K, which is like ~Dec. 29 J

Then, it’d be additional 3 days or so to go to 4.x K.  

 

Kin

 

From: sPHENIX-magnet-l [mailto:sphenix-magnet-l-bounces AT lists.bnl.gov] On Behalf Of EdwardOBrien
Sent: Monday, December 18, 2017 5:37 PM
To: sphenix-magnet-l AT lists.bnl.gov
Subject: Re: [Sphenix-magnet-l] ~255-260 K

 

    Hi Kin,
     Thanks for the update. All preparations seem to be going well.  Does
    the rate of cooling ever change, or is it linear all of the way down?
    If it is linear then we have 18 days left to go.

     Ed

On 12/18/2017 5:10 PM, Yip, Kin wrote:

Hi,

 

I attach the latest screenshot of the Cryo HMI and you can see that the temperature sensors seem to be between 255-260 K.  The cool-down rate is

slightly faster than 0.6 K per hour.

 

--- Pablo Rosas is trying to finish his power supply test.   The last part should be the short-circuit (which he’s probably already started to set it up …

    I didn’t manage to catch him this late afternoon. )  

 

--- Frank Toldo/Paul Giannotti have connected all the strain gauge/linear pot cables and it seems that Frank just needs to finish all the termination

     tomorrow.

 

--- One of the strain gauge J cable has a deformed plug and Richard Meier has agreed to fix it, as he dealt with it before J 

 

--- Zeynep has moved her $40K PXIe in the 912 quench-detector Rack.  Frank has also helped provide us with power strip with long-enough cord.

 

Kin

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