High Vacuum Gauges For Dummies

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ian_krase
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High Vacuum Gauges For Dummies

Post by ian_krase » Fri May 19, 2017 6:52 am

Does anybody have a source for a simple, practical guide on what kinds of high vacuum gauges (probably mostly ion gauges of the cold and hot types) are out there, what are good types to buy used, what is compatible with what? There seems to be a lot less accessible non-vendor-specific documentation on these than there is on heat loss gauges.

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Dennis P Brown
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Re: High Vacuum Gauges For Dummies

Post by Dennis P Brown » Fri May 19, 2017 12:52 pm

Don't know of any up-to-date sources but theory of operation on many types of gauges can be found in wiki.

For high vacuum I bought two hot filament ion gauge tube readers with cables (these tend to be very cheap; don't forget the cable is needed and tubes are universal on pin connection; I only purchase from people that allow returns) and an ion gauge tube with a proper KF adapter system included (notice the logic here); again, fairly cheap compared to the cold cathode systems.

The cold cathode systems cover a huge range - from 10^-8 torr up to tens of torr. Just too expensive for me. The similar hot cathode systems are not as common now but might be cheaper for that reason.

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Re: High Vacuum Gauges For Dummies

Post by Andrew Seltzman » Fri May 19, 2017 4:53 pm

I would strongly recommend going with a full range gauge with both digital and analog output. They are available pretty cheap used and will cover atmosphere to 1e-10 torr.

The MKS quattro 999 has integrated piezo, pirani, and hot cathode and will automatically switch the hot cathode on/off at the appropriate pressure to avoid filament damage. It has both rs232 and analog outputs and is programmable to correct for gas type automatically. I have control code written in matlab for these gauges if you need it.

http://www.ebay.com/itm/MKS-Series-999- ... Sw8gVX~JjY

http://www.ebay.com/itm/MKS-Series-999- ... SwiylXCB8y

Also the MKS 901p is an analog/digital loadlock transducer with both pieze and micro-pirani detectors (atm to 1e-5) (also gas type programmable), I have some of these but haven't tested them yet:

http://www.ebay.com/itm/NEW-TAKE-OFF-MK ... 2459958508

Here is a good reference from MKS:
https://www.mksinst.com/product/categor ... goryid=523
Andrew Seltzman
www.rtftechnologies.org

ian_krase
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Re: High Vacuum Gauges For Dummies

Post by ian_krase » Sun May 21, 2017 1:35 am

Thank you very much everyone.

Am I correct in my impression that the glass tube hot cathode ion gauges are broadly all compatible with each other as long as the cable pinout is correct? How does one get the calibration -- which I understand to be somewhat unstable on ion gauges -- or is it intrinsic to the tube to some degree?

I actually have a loadlock pirani/piezo gauge similar to that one you linked, but bulkier and with the pirani part based on the Convectron 275. So far I've primarily used the pirani component. It has a built in display, which is a help with my somewhat compact system -- I have a somewhat "analog"-ish preference.

I'm surprised to hear that cold cathodes are expensive -- there seem to be a number of cheap ones on Ebay.

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Re: High Vacuum Gauges For Dummies

Post by Jerry Biehler » Sun May 21, 2017 5:01 am

Generally you can use any hot cathode tube on any B-A controller. There are some more odd-ball tubes out there as well as controllers that are pretty specific. You just have to do proper research on the controller you are looking at. Most older controllers will work with the standard nude or glass ion gauge tubes. FWIW cold cathode gauges are considered to be less accurate than hot cathodes.

I have a couple of the pfeiffer full range gauges and they are pretty nice. I wrote a little arduino program to decode the analog output.

ian_krase
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Re: High Vacuum Gauges For Dummies

Post by ian_krase » Tue May 23, 2017 8:42 am

How about the MKS/HPS 919? There's a bunch on Ebay for super cheap.

Only problem is that it doesn't have the pinout for its cable in the manual. Does anybody know it?

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Re: High Vacuum Gauges For Dummies

Post by Jerry Biehler » Wed May 24, 2017 8:44 am

MKS 919 is very common and will run standard tubes, I have a relabeled one. The manual is online somewhere, thats where I got it. If it does not have the cable it is going to be annoying since they use the high power D-Sub connectors for the filament/degas power.

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Re: High Vacuum Gauges For Dummies

Post by ian_krase » Sat May 27, 2017 8:49 am

Jerry,

I bought one. (An MKS 919)

I don't have the cable, but I can source D-sub high current connectors or make appropriate modifications. However, I'm curious as to whether you can send me the pinout to the cable / the D-sub connector. The manual doesn't contain it (assumes you have the factory cable) and so I'm trying to reverse engineer.

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Re: High Vacuum Gauges For Dummies

Post by ian_krase » Fri Jun 23, 2017 4:56 am

I found a mobile connector (similar to connectors used for ham radio mics) that was rated for both the relevant currents and relevant voltages, and used it.

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