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My Attempt at a DIY Ionization Gauge

Posted: Wed Jan 03, 2018 10:33 am
by ian_krase
Here's my take on a Bayard-Alpert gauge.

I honestly have no idea if this will actually work, it may very well need some tweaks. Once I get my hands on an electrometer and some more DIN rail power supplies, I will try actually driving this gauge to see if I can get some measurements out of it, and whether they agree at all with my actual ionization gauge.


The idea is to get some familiarity with electrostatics and ions for my future mass spectrometer project.

MVIMG_20180103_005711.jpg

Re: My Attempt at a DIY Ionization Gauge

Posted: Wed Jan 17, 2018 8:29 am
by ian_krase
It works!

Collector at ground, grid at about +28V, filament biased to between +2V and +5V to prevent electrons from hitting the collector.

The exact filament bias voltage needs to be adjusted to zero the gauge. Filament emission current is about 70 microamperes.

Collector current is read out on the nanoampere or 10-nanoampere range on my new Keithley 610C electrometer, and cleanly tracks my real ion gauge as I vary the pressure between 3E-5 and 9E-4 torr.

(Yeah, my chamber is kinda dirty and the massive amounts of Hysol 1C are not baked out yet.

Getting this all set up, without really having purpose-made wiring, is a bit of a spaghetti factory. I sadly still don't have the parts needed to short all unused feedthrough pins to ground.

Re: My Attempt at a DIY Ionization Gauge

Posted: Wed Jan 17, 2018 9:42 pm
by JoseRey
you should calibrate it with a functional gauge and make 5 runs, take data, calculate averages and standard deviation and plot it, it'd give you a great insight and would look much more professional

greeting

Re: My Attempt at a DIY Ionization Gauge

Posted: Wed Jan 17, 2018 10:11 pm
by JoseRey
Actually this reminds me of this cryogenic thermometer Cody's lab made

https://www.youtube.com/watch?v=VgdaRXKIDNQ&t=582s

Re: My Attempt at a DIY Ionization Gauge

Posted: Thu Jan 18, 2018 5:26 am
by ian_krase
Yeah, this is mostly not so much meant as an experiment in metrology as a way to practice ion sources. An ion gun will come later.

Re: My Attempt at a DIY Ionization Gauge

Posted: Thu Jan 18, 2018 1:30 pm
by JoseRey
Keep informing then