I decided to test my Veeco diffusion pump using the 1402 that I have just refurbished. At the present I am using my Web site for documenting my experiments, which I don't mind sharing; it is very convenient for me; decided to share photos of my experimental setup.
The following link shows a photo of the 1402 backing the DP:
I don't have yet any 2" vacuum pluming; attached to the top is a quick adapter for the TC and ion gauge tube to sample the pressure. I plan to have something more suitable in the future. The ion gauge should be rotated 90 degrees; the tungsten heater is drooping slightly which I understand affects its sensitivity value.
The next link shows the TC gauge that was zeroed after the DP reached 0.1 micron.
The next link shows the CVC ion gauge controller;
The emission current is 1 ma. corresponding to slightly higher than 0.02 micron reading. At 10 ma. the pressure settles to about 0.06 micron; as expected higher than that at 1 ma. I believe this is due to enhanced electron space charge cloud.
I got two of these for very cheap; I wanted something very basic to learn from; I was able to fine the manual with schematics on the Web; before using, the emission current and electrometer were checked ( using my DVMs) for calibration. I was very surprised after so many years how close to calibration they were.
The last link shows the DP that I modified for the cooling fan I found in my junk box:
Having no information regarding this DP; I decided to try using about 70 cc of the Specialty Fluid 704 equivalent ( at the time it was the cheapest that I could find); The Variac, for the heater, was finally set to 100 VAC corresponding to the above results; don't know for the this fluid type what the optimum Variac setting should be.
Regarding the ion gauge reading ( 1 ma. emission) assuming the typical sensitivity value given for ( N2 or air). I do know that I started with air; however what I don't know is what the ion gauge is ionizing ( out gas ; back streaming etc); Out gassing in the ion gauge itself; I didn't do much degassing yet. I don't know typically how close to the typical sensitivity value given should be trusted. I am a novice getting my feet wet just learning how to drive. My goal is to eventually get down near 10-6 Torr someday for electron beam experiments that I have in mind.
