Thanks for sharing Vaughn, nice setup. I'm also learning and
gathering equipment. I have a gauge controller that I can't find any
information about and will have to reverse engineer it to use. Can
you give me the links to the manual and schematics for your
controller (or email it to me) as it will help me understand mine a
bit better please.
I look forward to seeing your progress.
Don Black.
On 18-Feb-13 5:44 AM, Vaughn Mcdowell wrote:
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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.
