Lingchao and fellow NMR enthusiasts,
I am also interested in how the AMMRL community suggests to go about this. We are preparing to quench our old Oxford 400 magnet (1986 vintage) in preparation for a new Bruker system. Bruker suggested (unofficially) cracking the vacuum on the magnet and having a flow of nitrogen and helium gas over the liquid in the magnet. Any thoughts or suggestion? Things to watch out for? Safety concerns?
Justin Mobley, Ph.D.
NMR Center Director
University of Kentucky
Department of Chemistry
Justin.Mobley_at_uky.edu
(859) 218-5777
> On Mar 6, 2018, at 2:41 PM, Lingchao Zhu <lzhu_at_chem.wisc.edu> wrote:
>
> Hello AMMRL,
>
> We have an old Thermo LTQ FT Ultra Mass spectrometer waiting for its retirement. (Model: Finnigan LTQ FT Serial No: SN06036F) It has a horizontal Oxford magnet(Part No: AJH0280) and we are not going to reuse this magnet. We don't have any magnet book or charging rod of it. According to the student in the lab, it has 7T magnetic field.
>
> Without too much information from the lab, we decide to dry-quench this magnet, meaning we will let the cryogen boiloff itself to induce a quench. I have following questions to ask and would appreciate any input from AMMRL community:
>
> 1. Should we let the liquid nitrogen go dry completely first and then waiting for all liquid helium boiloff? Or we need to keep filling liquid nitrogen until the liquid helium level is low then stop filling liquid nitrogen? Which way is safer?
> 2. Please see the attached photo for top part of this magnet. It has helium exhaust port built on top of it so when quench happens all the helium gas will blow out through this big pipe. Anything we need to check before the quench happens?
> 3. Any other important notes before the quench? We will definitely block the lab room when the cryogen is low.
>
> Thank you.
>
> Lingchao
>
>
> --
> Lingchao Zhu, Ph.D.
> Instrumentation Tech, MR Facility
> Department of Chemistry, University of Wisconsin-Madison
> 1101 University Ave, Madison, WI 53706 USA
> Tel: (608)262-8196
> Fax: (608)890-0468
> Email: lzhu_at_chem.wisc.edu <mailto:lzhu_at_chem.wisc.edu><horizontal magnet.JPG>
Received on Tue Mar 06 2018 - 16:08:33 MST