Ah, the fun of email. One never knows where they might end up....
My "old, old" comment forwarded to the group about Jane's magnets was
very poorly stated: in my head it was connected, in a humorous way, to
our "old, old" magnets here.
Our magnets are weirdly similar in age to those at UCLA, with two
installed in 1985, another 1988, and two more from 1993. Only the two
from 1985 have been rebuilt. Our 1988 (Oxford 500) magnet we're
watching closely, but is still normal in boiloff and refills. I have
been relieved to hear that others have similar ages with their magnet
seals, and are also doing ok.
Charlie
Zhang, Weixing wrote:
> Hello:
>
> I have already sent out a summary for my previous subject.
> Since many people are interested in this topic, I am more than happy to take a survey. If you send me the following information, I will summarize and post it to the group at once.
>
> 1) Field Strength and maker of your magnet.
> 2) At what year it is energized (or when the seal was replaced).
> 3) Current helium and nitrogen boil-off condition (compared to original spec)
>
> Thanks,
> Weixing Zhang
>
> -----Original Message-----
> From: Charles G. Fry [mailto:cgfry_at_wisc.edu]
> Sent: Friday, June 12, 2009 2:16 PM
> To: Zhang, Weixing
> Subject: [Fwd: Re: AMMRL: When the magnet seal should be replaced? - EXCELLENT QUESTION]
>
> Weixing,
>
> Jane's suggest seems a very good one; wow, her magnets are old, old (I
> didn't really think they last that long, but we've got one 21yr old
> magnet ourselves). In any event, and in the interests of not have a
> large number of email hit all our inboxes, I am hopeful that you will be
> willing to have people email you with the data, and then summarize the
> results for the group. If so, would you please communicate such to the
> group. If you're too busy, let me know back, and I will either do this
> myself, or try to get someone else that's willing...
>
> Cheers,
> Charlie
>
>
>
>
>
>
> Jane Strouse wrote:
>> Dear AMMRLers,
>>
>> This is a really good question for a survey. Some of us have some
>> seriously old magnets out there. We have several that are doing just fine,
>> but I worry about this even in the face of no symptoms. I think it would be
>> great if people with older magnets would provide some data. Here are the
>> ages of our older (some ancient) systems (including two located in our space
>> that belong to someone else):
>>
>> Oxford 300 MHz wide bore - installed 1988
>> Oxford 500 MHz narrow bore - installed 1985 - dewar refurbished 1993
>> Oxford 500 MHz narrow bore - installed 1986 - dewar refurbished 1993
>> Bruker 500 MHz narrow bore - installed 1993
>> Bruker 400 MHz narrow bore - installed 1994
>>
>> All of these systems appear to have no problems, i.e. hold time is the same,
>> no increase in boil-off, etc. The two that were refurbished were relocated,
>> so we took that opportunity to do it while there was a "moving" budget; they
>> were not indicating any problems prior to the refurbishments.
>>
>> Jane
>>
>> Dr. Jane Strouse
>> Director, UCLA Molecular Instrumentation Center
>> (310)-825-9841 - voice
>> (310)-825-2280 - fax
>> strousej_at_chem.ucla.edu
>> http://www.mic.ucla.edu
>> Office: Room 1410 Molecular Sciences Building
>> Mail: Box 951569
>> Shipping: 607 Charles E. Young Dr. East
>> Los Angeles, CA 90095-1569
>>
>>
>> -----Original Message-----
>> From: Zhang, Weixing [mailto:Weixing.Zhang_at_STJUDE.ORG]
>> Sent: Tuesday, June 09, 2009 12:37 PM
>> To: ammrl_at_ammrl.org
>> Subject: AMMRL: When the magnet seal should be replaced?
>>
>>
>> Hello everybody:
>>
>> We have two 600 MHz magnets and both of them are over 10 years old.
>> I heard that the seal will age and need to be replaced at certain time.
>>
>> I would like to know:
>> At what condition (e.g. He/N hold time, boil off rate) the seal must be
>> replaced?
>>
>> What is the longest time that the seal can last?
>>
>> Thanks,
>> Weixing Zhang
>> St. Jude Children's Research Hospital
>> 262 Danny Thomas Blvd
>> Memphis, TN 38105
>> (901)595-3169
>>
>>
>> Email Disclaimer: www.stjude.org/emaildisclaimer
>>
>
--
~~~~~~~~~~~~~~~~~~~~~~~
Charles G. Fry, Ph.D. Tel: (608)262-3182
Director, MR Facility Fax: (608)262-0381
Chem. Dept., 1101 University Ave, Univ. Wisconsin-Madison
Madison, WI 53706 USA email: fry_at_chem.wisc.edu
Received on Fri Jun 12 2009 - 12:14:02 MST