Hi Ken,
“Tuning of all X band nuclei begins to fail” is not clear enough—does
the tuning move off resonance or are you unable to tune the probe for some
other reason? One possibility is that the 31P experiments may be causing your
coil (or some other component in the probe) to heat for some reason, which would
affect all the X nuclei, and if it warmed up enough and started warming up the
1H coil, could cause it to detune as well.
And after you turn it off for a while things cool back down and go back to
normal (I assume you see the same if you just don’t pulse for a while?)
Anyway, that seems like a possibility to me.
Cheers,
Mike
> From: main_at_ammrl.groups.io <main_at_ammrl.groups.io> On Behalf Of Sham, Shing
> Sent: Thursday, September 14, 2023 8:04 AM
> To: main_at_ammrl.groups.io
> Subject: Re: [AMMRL] P31 issues on Varian ,MR400
Hi Ken,
If the problem is coming from the x-band amplifier, should it affect the C-13
as well?
Just my 2 cents. Good luck.
Simon
> From: main_at_ammrl.groups.io On Behalf Of Kenneth Sharp-Knott via groups.io
> Sent: Thursday, September 14, 2023 8:56 AM
> To: ammrl_at_groups.io<mailto:ammrl_at_groups.io>
> Subject: [AMMRL] P31 issues on Varian ,MR400
Hello Spinlandians,
I have a weird issue that I've been observing for years.
On my Varian MR400 of several P31 experiments are run in close sequence, the
tuning of all X band nuclei begins to fail. In fact it also begins to affect
the tuning of the proton channel to a lesser degree. It also obviously impacts
the sensitivity of those experiments drastically .My suspicion is that the low
band amplifier begins to overheat.
Our solution has been to not allow P31 on this instrument as C13 doesn't cause
this problem. For various reasons, I would like to figure this out so that P31
is again available.
I'm doing some troubleshooting, but I think it begins to recover after being
off for a while. It might also be the synthesizer.
What is weird is that this consistently happens after running a series of P31
experiments.
Any thoughts on this?
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Received on Thu Sep 14 2023 - 07:32:58 MST