Hi Zdenėk,
My guess would be that your analysis is the right one, the field having drifted
out of the range the BSMS can correct (the 'field' setting), due to the loss
over time of current in the superconducting coil. The quick solution is to
adapt the configuration of the spectrometer ('cf'): lowering the base frequency
(BF, probably 400.14 MHz), to e.g. 400.06 MHz, should move the lock signal
back into the usable range. Afterwards you may want to adapt your parameter
sets using 'paracon'.
In order to recover the initial base frequency of 400.14MHz, reboosting the
current in the coil would be required.
Regards,
Reiner
________________________________
From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> on behalf of Zdenėk To šner via groups.io <zdenek.tosner=natur.cuni.cz_at_groups.io>
Sent: Sunday, July 23, 2023 11:00 PM
To: main_at_ammrl.groups.io <main_at_ammrl.groups.io>
Subject: [AMMRL] tuning range shifts on BBFO probe
I would like to ask for opinions on our recent problem on Bruker Avance III=
HD 400MHz with a BBFO probe and a sample changer. It is our workhorse for
routine chemical characterization and runs under icon automation. The system
has been running nicely for almost 7 years. Recently, atma fails regularly
to tune the probe - the optimum tuning shifted towards the "left" border of
the tuning range. Two weeks ago, only chloroform samples had the optimum
tuning out of the range while water samples could still be tuned.. It seems
the tuning range continues to drift and most solvents cannot be tuned now.
What could be the cause? (Resetting the probe files / atma self-re-calibration
does not help)
Best regards,
Zdenėk
--
RNDr. Zdenėk Tošner, Ph.D.
Tel.: +420 221 95 1323
E-mail: zdenek.tosner_at_natur.cuni.cz<mailto:zdenek.tosner_at_natur.cuni.cz>
Laboratory of NMR Spectroscopy
Charles University in Prague
Faculty of Science
Albertov 6, 128 43 Praha 2
http://www.natur.cuni.cz/en
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Received on Mon Jul 24 2023 - 01:52:13 MST