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Sorry for the truncated last sentence. *Perhaps you could* measure the
voltage output from the board and see if that is normal.

Yuzhen

On Fri, Sep 28, 2018 at 10:31 AM Yuzhen Yan <[log in to unmask]> wrote:

> Hi Robert,
>
> If all of HVac, box/trap ratio, and signal intensity are fluctuating, to
> me this is a board issue. What you wrote also seems to be indicative of a
> faulty board:
>
> "We measured the Penning voltage and the trip point on the access points
> MP11/12/13 on the power distribution board of the Delta V. Voltage is
> between 2.1 and 2.2 Volt, which Isodat interprets as an extreme goor (or
> unrealistic?) vacuum. We are not able, of course, to switch on the ion
> source to see if we still have fluctuations on the signal. Wa also
> exchanged the cable between the Penning’s magnet housing and the board."
>
>
> FWIW, the Delta XP Plus in our lab recently had a similar (but not
> identical) vacuum/signal fluctuation issue. What's different is in our case
> is that box currents were stable. You could find a detailed description of
> symptoms in an email I sent back in Feb. It turns out to be a leak from a
> viton O-ring between the collector and amplifier housing.
>
> Perhaps you could
>
> Best,
> Yuzhen
>
>
>
> On Fri, Sep 28, 2018 at 6:35 AM Geldern, Robert van <
> [log in to unmask]> wrote:
>
>> Hi Wolfram,
>>
>> it is going through an UPS unit.
>> So I did not expect a problem here but I will see if I have the technical
>> equipment and knowledge to check.
>>
>> regards,
>> Robert
>>
>> > Am 28.09.2018 um 10:46 schrieb Wolfram Meier-Augenstein (pals) <
>> [log in to unmask]>:
>> >
>> > Hi Robert,
>> >
>> > Have you checked the power supply to the lab / IRMS? Is it stable and
>> within specs?
>> >
>> > Best,
>> >
>> > Wolfram
>> >
>> >
>> > Prof. Dr W Meier-Augenstein, FRSC
>> > Stable Isotope Forensics
>> > Robert Gordon University Aberdeen
>> >
>> > Sent from my BlackBerry 10 smartphone.
>> >  Original Message
>> > From: Geldern, Robert van
>> > Sent: Friday, 28 September 2018 08:27
>> > To: [log in to unmask]
>> > Reply To: Stable Isotope Geochemistry
>> > Subject: [ISOGEOCHEM] Unstable vacuum readings and signal on a Delta V
>> >
>> >
>> > Dear friends,
>> >
>> > after a week of struggling it is now time to ask four the wisdom of the
>> community.
>> >
>> > I am in South East Asia trying to get a Delta V Advantage running. The
>> main issue was originally a regularly oscillating (2 sec interval) high
>> vacuum reading (fast changes between 5.8 and 7.9 x 10^-8) together with
>> fluctuations of the box/trap ratio and signal intensity. All four
>> oscillated together, visible as an up and down pattern in a time scan. For
>> the signal intensity it seems that the amplitude of the intensity changes
>> depended somehow on the m/z measured and were smaller for m18 (50mV)  but
>> extreme für e.g. m28 (50V).
>> >
>> > With ion source off we did no see any noise anymore in the detector
>> and/or the filament but the vacuum reading was still flickering.
>> >
>> > What we did so far:
>> > - replaced the fore vacuum rotary pump
>> > - cleaned all tubings from the fore pump to the turbo and removed all
>> oil contamination
>> > - changed the oil wick of the large turbo (small is not installed)
>> > - checked ion source connections and changed filament, just in case
>> > - removed the Penning gauge and cleaned the tube mechanically
>> >
>> > After re-assembling everything the instrument started smoothly within a
>> couple of minutes. The turbo and fore vacuum sound is OK.
>> >
>> > However, vacuum readings are now far off and still flickering. Reading
>> on Isodat is now 6 x 10^-10 and 2 x 10^-9. This is totally unrealistic and
>> we do not get a green light on the vacuum LED on the front panel. Obviously
>> Isodat also thinks that is out of range? I did not find a documentation
>> about a lower end trip point, only about the upper set point (meaning when
>> your vacuum is not good enough).
>> >
>> > We measured the Penning voltage and the trip point on the access points
>> MP11/12/13 on the power distribution board of the Delta V. Voltage is
>> between 2.1 and 2.2 Volt, which Isodat interprets as an extreme goor (or
>> unrealistic?) vacuum. We are not able, of course, to switch on the ion
>> source to see if we still have fluctuations on the signal. Wa also
>> exchanged the cable between the Penning’s magnet housing and the board.
>> >
>> > From my current interpretation we might have 3 options:
>> > - a broken Penning gauge
>> > - a broken/not correctly working magnet housing
>> > - a problem with the power supply or reading of the voltage on the
>> Delta V board.
>> >
>> > What I would appreciate are thoughts about further tracing down the
>> problem. Unfortunately we do not have a new Penning gauge or Magnet housing
>> at hand. Any options to cheat on Isodat or how to check if board supplies
>> the correct power to the Penning or to somehow calibrate the Penning?
>> >
>> > I also fully open to new suggestions regarding the original problem of
>> fluctuations in vacuum-signal-filament readings.
>> >
>> > regards,
>> > Robert
>> >
>> > --
>> > PD Dr. Robert van Geldern
>> > Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) | GeoZentrum
>> Nordbayern
>> > Schlossgarten 5 | 91054 Erlangen | Germany
>> > [log in to unmask] | www.gzn.uni-erlangen.de
>> >
>> > ----------
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>> --
>> PD Dr. Robert van Geldern
>> Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) | GeoZentrum
>> Nordbayern
>> Schlossgarten 5 | 91054 Erlangen | Germany
>> [log in to unmask] | www.gzn.uni-erlangen.de
>>
>
>
> --
> Yuzhen Yan
> PhD Candidate
> Guyot Hall, Department of Geosciences
> Princeton University, Princeton NJ 08540
>
> --
> Yuzhen Yan
> PhD Candidate
> Guyot Hall, Department of Geosciences
> Princeton University, Princeton NJ 08540
>