sPHENIX discussion of the superconducting solenoid

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

Hello,

 

Please be reminded of today’s sPHENIX Magnet Biweekly Meeting at 1:30 pm.

 

You could read from Roberto’s  and Paul Orfin’s message below.  The cold weather froze the little moisture/water causing the fail-safe

ODH valve --- i.e Paul taught me : when something fails, it fails to close the valve to prevent more LN2 from coming in ---

to block the LN2 line.   I noticed it after 9 pm … I understood from Paul that he tried to ask CAS to try different things last night

but they only figured out/solved the problem this morning.

 

Now, the LN2 has been back.  Unfortunately, the temperature rose last night.   Not so much for the magnet coil which is still ~105 K now.

I made a plot : “2018-1-3 Magnet Coil Temperature.JPG” which plateau-ed after Paul shut down LN2 line when he realized that there was no

cold LN2.    But the temperature sensors at the splice joints (we added for the Extension) rose beyond 115 K at one point.   Presumably,

the large volume of Magnet Coil was more difficult to be warmed up (and cooled down) compared to the splice joint area.   So, we called off

the Hipot at least for today.

 

More discussion in the meeting ……..

 

Kin

 

 

From: Orfin, Paul
Sent: Wednesday, January 03, 2018 9:20 AM
To: Yip, Kin; Than, Yatming (Roberto)
Subject: RE: LN2 LOST

 

Kin,

 

Air line blockage was freed.  LN2 line has finally cooled down and is beginning to fill the precooler.  We are looking to replace the control air line with a larger diameter to limit any internal frost build up.

 

We will begin cooling again today.

 

Thank you,

Paul Orfin
Cryogenic Systems, Collider-Accelerator Department
Brookhaven National Laboratory
Telephone: (631) 344-2899

 

From: Yip, Kin
Sent: Wednesday, January 03, 2018 9:18 AM
To: Than, Yatming (Roberto) <ythan AT bnl.gov>
Cc: Orfin, Paul <porfin AT bnl.gov>
Subject: Re: LN2 LOST

 

Hi,

 

You will try to restart/cool down the plant today ?

 

Kin

 

 

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

From: Than, Yatming (Roberto)

Date: Wed, Jan 3, 2018 8:13 AM

To: Yip, Kin;

Cc: Orfin, Paul;

Subject:LN2 LOST

 

 

Kin,

We lost air to the isolation valve at the liquid nitrogen storage dewar.

We froze water and plugged the line, and the valve closed on the spring Failed Closed air actuator.

 

 

 

Attachment: 2018-1-3.JPG
Description: 2018-1-3.JPG

Attachment: 2018-1-3 Magnet Coil Temperature.JPG
Description: 2018-1-3 Magnet Coil Temperature.JPG