“As part of an ongoing project of mine here, documenting the ongoing progress of my foray into the world of Ultra High Vacuum particle physics, it came to the part of the project that required some electronics and coding.
I purchased a surplus MKS series 903 IMT cold cathode vacuum gauge, with no controller or readout. For some background, ultra high vacuum systems need various sensor stages to properly measure the lack of gases in a chamber. As you get a stronger and stronger vacuum, the more complicated this measurement ends up.
At low vacuum, or rough vacuum, simple thermocouple gauges can do the job, but as you remove more and more from the chamber, you need something akin to an gas ionization gauge. The two most common methods are hot cathode and cold cathode gauges. Hot cathode gauges function like many vacuum tubes, in which they have a filament that boils off free electrons, which are accelerated towards a grid. Any gas molecules in the way will ionize and trip the sensor. Cold cathode gauges use a high voltage with no filament inside a magnetron to produce an electron path that also ionizes local gas molecules and trips the sensor.
My gauge is known as an inverted magnetron transducer gauge, made by MKS, which integrated the control electronics in with the gauge hardware itself. However, the output is a linear voltage that coincides with a logarithmic scale used for measuring vacuum. This is what we will be programming our arduino to do.”