Issues after installing new electron multiplier

[TraceWA]

Hi all, long time lurker and learner, first time poster

Our lab has a thermo trace 1300 paired to an ISQ 7000. The electron multiplier was on its way out so I've gotten a replacement from thermo. I've replaced the multiplier before but this time it's been more problematic

Firstly I replaced the multiplier just before the easter long weekend, the manual recommends keeping the multiplier in vacuum for at least a day and I thought over the weekend would be perfect. Also gives plenty of time to get the vacuum nice and stable. I also made sure that the connection from the multiplier to the holder was secure as I've previously had issues with it getting dislodged while putting the assembly back in.

I come in yesterday and do my checks, there's no leak, the vacuum is in my normal operating range (around 60mTorr) and so I do as the manual says, I go into the air & water/Tune dialogue and I reset the multiplier values. Then I go into the autotune and set a tune that will set the detector gain to 3*10^5, this is the EI full tune that comes with the software.

Things seem okay, however at this point I notice the autotune is getting stuck at the "setting Q1 voltage" step. Checking the dashboard at the same time it seems the software is pushing up the voltage of the multiplier and then cycling through Q1 voltages, repeating ad nauseum until eventually giving up.

I've troubleshooted as much as I know how to, I even made sure that I didn't accidentally put the same one back in while I was meant to be changing them. It may well be that there's an issue with the quadrupole that i'm not aware of but as far as I can tell the only thing that's changed IS the multiplier. I'm starting to wonder if I simply got a dud or if there is something else that was wrong that the change revealed.

There doesn't seem to be any blockages or bits in the way, I made sure everything was clean.

I HAVE e-mailed thermo requesting assistance, if they have sent me a dud I'm hoping they'll make that right but I was wondering if anyone else has any input or advice?

Right now I'm going to put the old one back in and see if I can use the last tune file i had as I do need to get this system up and running ASAP. The old multiplier is very much near an end but it is my only other option right now.

[TraceWA]

Having attempted to check the previous one. It unfortunately is spent it seems. a very straightforward "voltage too high" error.

[TraceWA]

Update

working with thermo service rep, the best thing we can tell is that there's nothing inherently wrong with anything other than, most likely, the multiplier itself. diagnostics all come back clear, the multiplier is definitely seated correctly, nothing looks bad from her end. She says everything has been done correctly, there isn't really any good reason why i'm only getting noise.

Looks like we're going to try and RMA the multiplier back to thermo under warranty and try again with a new one. Not fun considering i'm in WA and everything Thermo is over east.

[LALman]

Sounds like you are on the right track. Good luck. Hope its not your sideboard (or Thermo equivalent). That would be your next thing to check if it were an Agilent MS.

[TraceWA]

Sounds like you are on the right track. Good luck. Hope its not your sideboard (or Thermo equivalent). That would be your next thing to check if it were an Agilent MS.

That's absolutely a concern, But I've been told that if that were the case I would see voltages not being correct in the dynode and the multiplier readouts in the software on top of a fail showing up in diagnostics, either way, i'm going to be spraying compressed air in a few spots to make sure there's no chance of dust being in the wrong place. I'm also going to be checking the ion source and the pathway there to make sure there's no blockages of any kind

[TraceWA]

I may as well update

The warranty electron multiplier arrived today. I've just installed it and powered the system back on. I never stopped trying to get the last one to work and By the end I could just about see what could be air/nitrogen. but orders of magnitude too small. the calibration gas also barely showed up above the noise.

I've also cleaned our ion source, I have it practically gleaming at this point. I also double checked the connection the ion source has to the instrument and that's rock solid (Just in case something was bent slightly or worn down) and ensured the calibration solution is filled (there's plenty) AND that the line from there to the transfer line (where it ends up) is tight.

Hopefully when all is settled down and conditioned I'll get a clean tune and put this ordeal behind me.

[TraceWA]

Welp, having left it for the weekend, the good news is i can now see tuning compound peaks. the bad news is it's still very very noisy and the most important feature (100) which is used for the initial tune is barely visible.

So now I can rule out the multiplier most likely. i'm seeing far better results. but still not functional.

I'm now focusing on the ion source.

I have noticed (i have two ion sources, i swap them out when one needs a cleaning) when i removed the ion source to test the other one (waiting for temps to stabilize right now) that there was an odd ion burn mark on it. I use the extractabrite source with VPI, meaning that as long as i cool it first i don't have to pump down to swap it. the end piece, i think it's the lens3/RF lens. It looks like the other lenses but has 4 flat prongs for interfacing with the instrument.


on one of them there was an intense, triangular ion burn, it looks like there was an intense focused beam there, possibly something is out of alignment? what it would be though i have no idea.



https://imgur.com/a/lXU2nyQ