Cleaning Electron Multiplier?

[James_Ball]

I know that some electron multipliers like the ETPs can be cleaned with solvent, but can the new Triple Axis Detector horns from Agilent be cleaned in such a way, and if so what solvent would be compatible?

Our new 7000QQQ has been having a problem were after a while we get a constant background across all mass ranges, like a wall of spectral hits for almost ever mass at about 400 counts even with the emission off. We had the HED/Detector assembly replaced after two weeks service and now it is doing it again. I have a call into Agilent for service but I was wanting to see if it could be just something on the detector(shouldn't be since I haven't run anything but volatiles standards on it so far). I have the assembly that was taken out the first time and thought I could try cleaning it to see if maybe that would work. It is probably just a faulty board somewhere in the system but who knows.

[Bigbear]

Cleaning what? If your rough pump isn't backstreaming then according to theory all the EM "sees" are electrons. Sounds to me like it's something electronic.
I would call Agilent again.

[lmh]

I've heard of people trying to eke out a little more life from very old EM-horns in older quadrupole systems, but even there it was always a bit of a marginal activity. If you have a new instrument, you shouldn't have to do anything so drastic (or certainly not for quite a while). Yes, contact Agilent!

[James_Ball]

Agilent sent a new HED/EM assembly so I will install that probably tomorrow. From working with the 5973s I know you can get noise if the HED becomes contaminated and the one in the 7000 has way more surface area than the ones in the 5973s so more to be contaminated I imagine.

I remember many years ago J&W let some bad columns get past QC and we got one of those and it wiped out the analyzer on a 5971 because the phase cooked off the column, I don't think this is happening here, but it does make me wary from past experience.