[Esr-users] Hal B Buffer work

[Steven Lassiter]

Lets us know your schedule when you have it and we will work with you and Cryo on getting all this done.

Steven
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From: Esr-users <esr-users-bounces at jlab.org> on behalf of Steven Lassiter <lassiter at jlab.org>
Sent: Thursday, April 28, 2022 1:42 PM
To: Denny Insley <dinsley at jlab.org>; Amy Comer <acomer at jlab.org>; Cryo <esr-users at jlab.org>
Subject: Re: [Esr-users] Hal B Buffer work

Hi Denny,

We are in the process of re-calibrating the liquid level probes on the SHMS magnets, before the meters are replaced with newer units. Then we will repeat the re-calibration with the new meters. Both Helium and LN2 probes.

This procedure requires the warm return for the magnet being calibrated to open at the end of the calibration process, to remove the heat buildup within the magnets He supply U-tube. This is normally just a small burp and ESR doesn't see any changes or additional load.

But there is always a chance that the system burps too much - ie yesterday when a He supply valve was shut too fast (had functioned well two times prior the week before) and the sudden drop in He flow results in the Hall's transfer line stalling. Then all the magnets starve and more of them go on warm return, loading up ESR's recovery. ESR placed another recovery pump on online for additional capacity, but the system recovered without needing it (I think).

Also, as this is the last month before the hall closes up, Hall C will be doing spectrometer check outs, ramping magnet to full currents. There is a possibility that some magnets (the HB and the SHMS dipole) may experience some re-training, but this is unlikely - still a chance.

So there can be additional loads on the the warm return coming up. Also any warm return burps from the other halls will result in a current lead flow interlock to the Hall C magnets, resulting in a fast discharge (not a quench),  which will produce even more warm return flow back to ESR.

The Hall C schedule is to preform probe calibrations tomorrow and next week, followed by spectrometer check out around the middle of May.

Hope this helps.

Steven
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From: Denny Insley <dinsley at jlab.org>
Sent: Thursday, April 28, 2022 12:24 PM
To: Steven Lassiter <lassiter at jlab.org>; Amy Comer <acomer at jlab.org>
Subject: Hal B Buffer work

Good afternoon,

    I wanted to touch base with you about the work that we are going to have to do on our buffer Dewar.  We have to reconfigure to accept a new transfer line to the incoming polarized target.  To do that we are going to have to go to warm return and let the buffer Dewar warm up some before removing the distribution can and stabbing the new transfer line.  I will let you know more precisely when we are ready to start once we finalize a plan.  Let me know what concerns or questions you may have as I am not sure what you have in the works at the moment.

Thanks,


Denny Insley

Physics / Hall B Work Coordinator

dinsley at jlab.org

office: 269-6071

cell: (757)897-9060


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