John Thoburn wrote:
> Dear ammrlers,
>
> We have 400 MHz Oxford magnet with no vibration dampening, resting on
> a concrete floor of a single story builiding with no basement. We can
> see what we believe are room vibration effects - peaks 180
> out-of-phase equally dispaced about a central line of a chloroform
> sample. They are in some cases about half the intensity as the 13C
> satellites.
>
> While we expect to see some peaks, we are surprised how large they
> are. Will vibrational dampening eliminate these peaks? Does anyone
> have a sense of what is "good" or "acceptible" as far as these
> vibrational peaks are concerned, either with or without dampening? Are
> there any criteria or guidelines for this?
>
> Thanks,
>
> John Thoburn
> jthoburn@scuacc.scu.edu
> phone: 408-554-4796
> fax: 408-554-7811
>
> Department of Chemistry
> Santa Clara University
> Santa Clara, CA 95053
John,
We have a Inova 500 in the basement of a 5 story building (nothing below
us but earth). It has TMC antivibration legs. In the nonspinning
chloroform lineshape test we see no sidebands at all other than the 13C
satelites. Varian evaluated our site before we installed this instrument
and told us we were a little above specs for building vibration. They
have equipment to monitor this. If we depressurize the TMC legs we do
see some sidebands due to vibration.
Charlie
--
Charles L. Mayne
University of Utah
Dept. of Chemistry
315 S. 1400 E. Rm Dock
Salt Lake City, UT 84112-0850
Voice: (801)581-7413
FAX: (801)581-4763 or 8433
E-mail: mayne@chemistry.utah.edu
http://www.chem.utah.edu/chemistry/facilities/nmr/nmr.html
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John Thoburn wrote:
Dear ammrlers,John,We have 400 MHz Oxford magnet with no vibration dampening, resting on a concrete floor of a single story builiding with no basement.=A0 We can see what we believe are room vibration effects - peaks 180 out-of-phase equally dispaced about a central line of a chloroform sample.=A0 They are= in some cases about half the intensity as the 13C satellites.
While we expect to see some peaks, we are surprised how large they are= =2E=A0 Will vibrational dampening eliminate these peaks?=A0=A0=A0 Does anyone ha= ve a sense of what is "good" or "acceptible" as far as these vibrational peaks= are concerned, either with or without dampening? Are there any criteria or guidelines for this?
Thanks,
John Thoburn
jthoburn@scuacc.scu.edu
phone: 408-554-4796
fax:=A0=A0 408-554-7811Department of Chemistry
Santa Clara University
Santa Clara, CA 95053
We have a Inova 500 in the basement of a 5 story building (nothing bel= ow us but earth). It has TMC antivibration legs. In the nonspinning chlorofo= rm lineshape test we see no sidebands at all other than the 13C satelites. Varian evaluated our site before we installed this instrument and told us we were a little above specs for building vibration. They have equipme= nt to monitor this. If we depressurize the TMC legs we do see some sidebands= due to vibration.
Charlie
=A0=A0 --
Charles L. Mayne University of Utah Dept. of Chemistry 315 S. 1400 E. Rm Dock Salt Lake City, UT 84112-0850 Voice: (801)581-7413 FAX: (801)581-4763 or 8433 E-mail: mayne@chemistry.utah.edu ht= tp://www.chem.utah.edu/chemistry/facilities/nmr/nmr.html
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