sPHENIX discussion of the superconducting solenoid

[Kin Yip <kinyip AT bnl.gov>]

Hi,

Thanks Bob for doing the calculation.   Bob asked me the issue of NEW voltage taps and any current-limiting resistance for the
extension that we're going to build ?

Do we already have new voltage taps and current-limiting resistance for the extension ?  I heard people mention it but I'm not
sure whether they're already built-in.  I understand that they're easy to add when we do the assembly but it'll be a shame if we
somehow forget about them.

... Paul just told me that he didn't include them ... but maybe, I'll look for Piyush (or who ??) to make sure that we have the taps/current-llimiting
resistance when we do the assembly ...

Kin

-------- Forwarded Message -------- Subject: RE: Closing this ticket this way ?? Date: Wed, 6 Jul 2016 10:56:12 -0400 From: Lambiase, Robert <lambiase AT bnl.gov> To: Kovach, Paul E <kovach AT bnl.gov> CC: Yip, Kin <kinyip AT bnl.gov>

This time with the attachment.

 

Bob

 

--------------------

 

Hi Paul, 

 

I’d still like the sketch I asked for below, But I can say the lead design is very conservative.

 

·         With a current of 4.7kA and a time constant of 33 seconds, the Miits requirement is 4.7² x 33 / 2 = 364 Miits ·         The smallest cross section of the stabilizing copper is 46mm x 12.7mm.  This gives a cross section area of 4.6 x 1.27 = 5.84cm². ·         The cross section of RHIC 30 strand superconductor (dipole cable) is 0.1166cm x 0.973cm.  Two are being used, so the area is 0.227cm².  I remember that the 23 strand cable had a critical current of 11kA in 0T field, so two 30 strand cables might be overkill.  It won’t hurt anything to have two. ·         According to the calculation, 364Miits will bring the temperature up to about 20K.  That is a big hunk of copper you have there.

 

I have given Kin the basis for my calculations.

 

Bob

 

 

------------

 

Hi Paul,

 

Because I’ve been away from this for a bit, could provide a little more information?

 

It would be ideal for me if you had a sketch which showed each segment from the coil to the outside world.

 

Each of the segments in this sequence would show what superconductor is used (where superconductor is used),  the cross sectional area of the stabilizer, where the voltage taps are, and whether each of these segments were in place for the 100 Amp test.

 

This would give me a better idea of all the pieces are, allow me to correlate the links to the 100 Amp test data, and make sure all the inputs to the quench detector are accounted for.

 

Thanks,

 

Bob

 

From: Kovach, Paul E
Sent: Tuesday, July 05, 2016 9:40 AM
To: Yip, Kin
Cc: Mills, James A; Lambiase, Robert; O'Brien, Edward; Anerella, Michael D
Subject: RE: Closing this ticket this way ??

 

The jpeg called “sphenix extension lead bus” is the copper busses that carry the superconductor through the extension. They are the same dimensions as the copper leads in the Ansaldo lead box and have the superconductor soldered along their length. They are 46mm x 15mm cross section. The flags on the end are 46mm x 50mm lap area as in the valve box.

The JPEG’s called “sphenix lead bus jumpers” and “sphenix lead bus” are the copper jumpers that connect the lead bus extension to the valve box leads at the far end. Their cross section is 46mm x 12.7mm.

The JPEG called “sphenix lead assy” shows the laminated copper flex leads at the magnet end of the extension connected to the lead extension bus. Their cross section is 46mm x 15mm.

The JPEG called “sphenix copper flex bus” shows the flex leads connecting the extension leads to the magnet flags.

What this means is that all the copper busses connecting the original magnet lead flags to the original lead box flags are 46mm x 15mm cross section except for the short jumpers at the lead box end of the extension which are 46 x 12.7mm cross section. All the lap joints are the same as the original Ansaldo joints (46mm x 50mm).

The super conductor is doubled RHIC dipole superconductor.

Roberto has assured us that there will be no temperature gradient along the leads.

 

 

From: Kin Yip [mailto:kinyip AT bnl.gov]
Sent: Friday, July 01, 2016 3:52 PM
To: Kovach, Paul E
Cc: Anerella, Michael D; Mills, James A; Lambiase, Robert; O'Brien, Edward
Subject: Re: Closing this ticket this way ??

 

Hi Paul,

Based on the conversation that we've just had with Bob Lambiase (on the phone), it seems useful
or even necessary that you show us the stabilizer and the superconductor (you're picking or have picked),
and then Bob can calculate to see whether it'd hold in a quench.

Since the extension is going to be made soon, I feel that we should do this calculation as soon as possible.

Just to reinforce what I said minutes ago : we'll appreciate if you can send us the stabilizer/superconductor
details as soon as possible.   Your cooperation will be most appreciated.

Kin

On 07/01/2016 03:00 PM, Kin Yip wrote:

Hi,

I've just talked with Paul in SMD.   His philosophy is that he's built everything the same as BaBar did and in fact, he kind of had to
in order to match with the old material/structure that BaBar has left us.    Since the BaBar stuff worked during quench or whatever,
it should also work for us.   He told me that he can't do any other verification.

Obviously, we're building the extension and I guess nobody seriously object to this.   It's too late anyway.   

May I or we close the ticket by saying along the line like what I've stated above  ??

Kin

On 06/23/2016 04:29 PM, Kin Yip wrote:

Dear Paul and Mike,

Ed is asking ... and I found this email that I sent to you in Feb. 2016.   It's about the ticket 34:
(in https://www.phenix.bnl.gov/~irina/sPHENIX/allcomments.php ):

"Verify that the temperature rise and energy loss due to a quench, at the transition from the superconductor/aluminum matrix to superconductor/buss flags, will not melt the superconductor or adversely damage the connection. If through calculations, it is shown that there is not enough thermal mass to stabilize this transition, ensure that an effective redesign of the joint will be made. (P. Kovach) "


Have you got any note (of any kind) or written something  to show that the above concern has been addressed so that we may close this ticket ???

Please help !

Kin

On 02/09/2016 12:33 PM, Kin Yip wrote:

Hi Paul,

Some paperworks/bureaucracy.

There are a few items in the RTS (https://www.phenix.bnl.gov/~irina/sPHENIX/allcomments.php) with your name.

The following one is probably done ?

  34

open

1.2

Magnet

Magnet Valve Box Extension Review

Verify that the temperature rise and energy loss due to a quench, at the transition from the superconductor/aluminum matrix to superconductor/buss flags, will not melt the superconductor or adversely damage the connection. If through calculations, it is shown that there is not enough thermal mass to stabilize this transition, ensure that an effective redesign of the joint will be made. (P. Kovach)

Magnet Oversight Committee (J. Mills)

P. Kovach

Since you've made the extension, can you write a statement to answer to the above question/request  so that we can this tikcet ??
That's, can you please just reply to the email with the statement so that I can help you close the ticket ?

Kin

 

 

 

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