We have Avance 400 MHz (Bruker). Our reading did not change for long time (couple weeks) as well. We called for the service and supplier determined the ice formation around the sensor. But, I think 4 days is not long time for the same reading unless the history of your NMR is different. We have sometimes for both NMRs same reading for 4 days and then it changed- it is normal for our spectrometers.
Thanks,
Ana Gudzon
Chemist ,Q.A. PDF
Covidien
60 Middletown Ave
North Haven, CT, 06473
United States
Office: (203) 492-7431 or lab (203) 492-7507
-----Original Message-----
From: Gopinath Tata [mailto:gopi_at_umn.edu]
Sent: Tuesday, February 18, 2014 4:10 PM
To: ammrl_at_ammrl.org
Subject: AMMRL: Helium fill problems
Hi,
I was doing helium fill for our 700 Agilent magnet on Friday Feb.14. It usually takes 30 minutes. But this time within 10 minutes helium was coming out, and I stopped the filling. The helium reading went from lowest number to highest instantly. The number did not change from past four days.
I have a feeling that there may be some ice formation. please let me know if you have any suggestions.
Thanks,
Gopinath
--
Tata Gopinath, PhD
Research Assistant Professor
Department of Biochemistry, Molecular Biology, & Biophysics http://www.chem.umn.edu/groups/veglia/people.htm
http://www1.umn.edu/nmr/ss.html
University of Minnesota
Minneapolis , MN 55455
Phone: 612-625-2715
Received on Wed Feb 19 2014 - 09:01:46 MST