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nanuc
NANUC Newsletter
November 2008
Nanuc800_2

Happy New Year to everyone,

We hope everyone had Happy Holidays and we wish everyone a very productive and successful New Year.
 
Sincerely,
 
NANUC Staff
National High Field NMR Centre (NANUC)
University of Alberta

 
IN THIS ISSUE
NANUC 500MHz
Infrastructure Monitoring
What's in your Dewar?
NMR Events
NMR Opportunities
Friends
Chenomx
JOIN OUR MAILING LIST
QUICK LINKS
The NANUC 500MHz
500_1
The NANUC 500 MHz was brought online in 1999.

Magnet
11.74T  51mm Oxford magnet (4.1K)

Console
Varian Inova console
XYZ gradients
4 complete channels with waveform generators

Probes

5mm HCN - xyz gradient

Computer & Power

Dell 755 with Linux running VNMRJ 2.2D-beta
4.0 kVa UPS for console
 
 The NANUC 500MHz system is the lab workhorse.  Many samples are initially run here before the 800MHz system to ensure sample stability.  Numerous small molecule spectra are run here for quality control and research purposes.  This magnet is by far the most stable in our collection with minimal drift and consistent shims.
Environmental, Infrastructure and Magnet monitoring
MonitorOutputLocal environmental conditions as well as magnet infrastructure status is monitored weekly in order to optimize performance and avoid expensive downtime.

So many variables can affect spectrometer performance from environmental temperature and pressure to electrical supply and cryogen performance.  Technical staff at NANUC rigorously monitor these variables to ensure optimal performance and maximum stability for spectra acquisition. 

The primary variable when dealing with NMR magnets is cryogen performance.  Cryogen levels are observed and documented during weekly scheduled liquid nitrogen fills.  Weekly boil of of liquid nitrogen should have a consistent value prior to filling.  Lower and lower weekly volumes may indicate outer vacuum container (OVC) issues, faulty filling procedures or level meters.  Cryogen performance can be observed via the boil-off gauge on the magnet leg.  Increases of He or N2 gas flow will be the first manifestation of OVC problems.  Increased He gas flow on a local 600MHz system was the result of deteriorating cryostat seals.  Quick recognition of the problem allowed for the safe de-energizing of the system and replacement of the seals in a timely fashion.

Environmental temperature and pressure play more and more of a role in spectrometer performance the higher the sensitivity becomes.  Room temperature conditions must be consistent in order to ensure a stable temperature for the sample within the magnet.  Varian's variable temperature (VT) systems have internal references within the console.  When there is a change in temperature at the console the VT will make appropriate adjustments to the heating of the sample in the probe.  At NANUC, the 800MHz console is in a separate room from the magnet.  A refrigeration unit in the console room., while keeping the room at an average temperature of 20°C, allowed the temperature to fluctuate 3°C.  The VT unit within the console compensated for this fluctuation by periodically heating the sample in the probe. The result was noise in the spectra associated with regular temperature fluctuations, not in the magnet room but in the console room.

Data from the monitoring computer is collected and modified and added to an Excel plot every week.  To download the data from the last 6 months of operations on the NANUC 800MHz .please click the PDF or EXCEL link to receive the desired file. (Jul.-Sept.) 2008-C.pdf 2008-C.xlsx (Oct.-Dec) 2008-D.pdf. 2008-D.xlsx
What's in your dewars?
Recently, when we were having pressure fluctuations within the upper bath of our 800MHz system we suspected that there may be a debris obstruction in the needle valve oriffice.  On pumped magnet systems, which the NANUC 800MHz is one, liquid helium is actively pumped from the upper helium bath through a cooling coil which cools a closed lower helium bath.  For more information on the mechanics of this see the pumped 800MHz portion of the NMRwiki

Figure 1
We have heard in the past that contaminants within liquid helium can be transferred to magnet helium dewar while filling.  In conventional static systems this is not as much of an immediate issue although the accumulation of debris, water and other condensed gases can present complications and dangers in the long run. It is difficult to determine the type of contamination may be present in a helium dewar.  It is always more efficient to maintain a small volume of helium at the bottom of the dewar to avoid the re-cooling process. This can cause accumulation of contamination and debris.

                                                                      Figure 2
This accumulation was observed in the NANUC 250L helium dewar when the filling tube extension (Figure 1) was brought out of the dewar with a core sample consisting of ice and other frozen gases.  After that incident the dewar was cleaned and a great deal of debris was found.  Ice and contaminating gases dried up or evapourated fairly quickly so it was difficult to evaluate how much there was.  Other physical debris included hair, rubber, brass filings and an O-ring! (Figure 2)

If you own your own helium dewar it might be worthwhile to warn it up and clean it out.  You may be surprised with what you find.  If you utilize rental dewars be sure to ask your supplier about their dewar cleaning schedule.  To be safe never place the filling rod all the way to the bottom of any dewar.  Who knows what you could be sucking up.
Events
September
Sept. 7-10       SMASH 2008, Small Molecule NMR Conference                              Santa Fe, New Mexico, USA
Sept. 8-15       Structure determination of bio macromolecules by solution NMR     Beijing NMR Center Beijing, China
Sept. 10-13     38th National Congress on Magnetic Resonance                             Bressanone / Brixen, Italy
Sept. 15-20     9th International Workshop on Magnetic Resonance                        Rostov-on-Don, Russia
Sept. 21-24     Reunión Bienal del GERMN / Reunión Ibérica de RMN                    Sevilla, Spain
October
Oct. 4-5                  21st Annual MOOT NMR Symposium                                                Windsor, Ontario, Canada
November
Nov. 12-14             47th Annual Meeting of the NMR Society of Japan                            University of Tsukuba, Japan
December
Dec. 7-11                 ANZMAG 2008                                                                                        Couran Cove, Queensland, Austrailia
February, 2009
Feb. 11-15               Magnetic Moments in Central Europe                                                             Otocec, Slovenia
Feb. 28 - Mar. 4       Biophysical Society 53rd Annual Meeting                                                       Boston, MA, USA
March, 2009

March 29-Apr 3      50th ENC, Asilomar                                                                             Pacific Grove, CA, USA
April, 2009
April 18-24              17th ISMRM Meeting                                                                      Honolulu, Hawaii, USA
April 21-22             2nd Int'l. Meeting on NMR & Quant. Analysis                                     Stockholm, Sweden
August
August 30-Sept. 4     10th International Conference on MR Microscopy                  West Yellowstone, Montana, USA

If you know of an upcoming NMR related event or are hosting one please send us the information and we'll post it.
Opportunities
Institution                             Position                         Location                     Contact / Link
Varian                                  Field Service Representative            Toronto, ON                           Varian NMR Canada
Varian                                  Research and Development              Palo Alto, CA                            Varian NMR
Varian                                 Technical Support Engineer               Walnut Creek, CA                      Varian NMR
Bruker                                 MRI Service Engineer                        Billerica, MA                              Bruker Biospin
University of Guelph           Post Doctoral Fellow                          Guelph, ON                                 L. Brown
Structural Proteomics         Post Doctoral Fellow                          Toronto, ON                                M. Deeton
University of Western Ontario     Post Doctoral Fellow                  London, ON                                G. Shaw
University of Western Ontario     Post Doctoral Fellow                  London, ON                                 J. Choy
University of British Columbia   Post Doctoral and Graduate        Vancouver, BC                         McIntosh Lab

If you have an NMR related position available please contact us and we'll post it.
NANUC staff are available for questions regarding NMR experiments, procedures, and support infrastructure.  If you have any questions regarding NMR and what it can do for you please contact us.  Collaboration opportunities are always available.

Sincerely,
 
Deryck Webb
National High Field NMR Centre (NANUC)
101 NANUC Bldg.
University of Alberta
Edmonton, Alberta
T6G 2E1
ph - (780) 707-0857
fax - (780) 492-9174