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Re: [Actris-acsm] Fwd: HB change and consequent AB drop during IEcal

Chronological Thread 
  • From: Véronique RIFFAULT <veronique.riffault AT>
  • To: MariCruz Minguillón <mariacruz.minguillon AT>
  • Cc: John Jayne <jayne AT>, Philip Croteau <croteau AT>, actris-acsm AT
  • Subject: Re: [Actris-acsm] Fwd: HB change and consequent AB drop during IEcal
  • Date: Tue, 8 Jul 2014 14:30:12 +0200 (CEST)
  • List-archive: <>
  • List-id: <>

Hi MariCruz,

we have not experienced that but there is something that seems equivalent in the AMS FAQ:

In particular,
"Heater bias is tied to ground
  • This indicates a short somewhere in (probably) the TOF
  • Thermocouple wire touching anywhere on the assembly would induce this problem
  • Note that the HB voltage is also applied to the thermocouple, owing to its placement at the heater tip"
which would explain why you get problems with the vaporizer temperature if you have a problem with the heater bias voltage and the heater board ...
There are some indications of tests that you may also try to perform on your heater board (but not sure it is the same :/ )

Sorry, not sure that really helps,

De: "MariCruz Minguillón" <mariacruz.minguillon AT>
À: actris-acsm AT
Cc: "John Jayne" <jayne AT>, "Philip Croteau" <croteau AT>
Envoyé: Vendredi 4 Juillet 2014 10:09:57
Objet: [Actris-acsm] Fwd: HB change and consequent AB drop during IEcal

Hi ACSM-users

I hope your are doing well. We had a problem with our ACSM, and I would like to ask you in case you have an explanation/solution.

We performed an IEcal and sulfate RIE cal and we got a change in HB reading (although the set HB was NOT changed), with a consequent AB drop. Moreover, the vap T also changed, without changing the set V.

I am attaching the diagnostics plots from 24 to 27th June so that you can see:

- 25th June, I tuned SEM and HB to get AB signal at 10-7.
- 26th June: IEcal and sulfate cal
- 27th June: keeps sampling with still low AB

The IEcal constant was lower than usual (about 2.4, while the last one was about 5.2), but the AB during calibration was about 0.5e-7, so the ratio (IEcal constant/AB) is very similar, so it makes sense. But, still I think it is not good to do the IE cal with such a low AB.

What can be the reason for this HB change? How to avoid it?

Afterwards, I did the following:

- We stopped scanning

- We turned off vap and ionizer settings

- We stopped the prisma, close the DAQ

- We disconnect the power from prisma and connect again

- Everything on again with the same settings it was before and during IEcal

- Check AB signal with the mz cal mode scan: 0.95e-7

So now I get the same AB signal as before without changing any settings. I started scanning again.

And now the vapT signal is not stable, it decreases from 600C to about 580C, and these fluctuations seem to track those from AB signal. Is this an electronics problem? or something else?

Thank you in advance for your help. Best regards


Prof. Véronique RIFFAULT
Ecole Nationale Supérieure des Mines de Douai
Département Sciences de l'Atmosphère et Génie de l'Environnement
941, rue Charles Bourseul - CS 10838 - 59508 Douai Cedex - France
Tél. : (33) 327 712 604 / Fax : (33) 327 712 914

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