Ion gauge coated ceramics

Ion gauges work by using a hot tungsten filament to ionize gas molecules and then collect the ion current and convert that current to a reading in Torr, Pascal or millibar.

Over time the ceramics on the ion gauge feedthrough can become coated with tungsten or titanium. That coating is conductive and when the coating covers the entire length of the feedthrough then the resulting leakage current can affect the accuracy of the ion gauge or prevent it from working at all. The picture below shows an example of a coated ion gauge.

Usually once the ceramics are fully coated then the ion gauge needs to be replaced at a cost of $500.00 or more.

This blog post will show you how to remove the coating from the ceramics and restore normal operation of the ion gauge for about $15.00

The first thing that you will need to do is to buy some dental polishing tape.  I used some TDV diamond strips as shown below. You can get diamond polishing tape on Amazon.

With the filaments removed from the ion gauge, mount the ion gauge in a vise.  The ion gauge needs to be tight but not so tight that the flange warps.

Use the diamond strip in a back-and-forth motion to remove the coating from the ceramic.  Use a light touch as you want to remove the coating but not eat away at the ceramic any more than necessary.

Once you have the ceramic cleaned off, use a soft paint brush to clean the grid and to remove any small bits of ceramic from the flange. Note that all of the deposition does not need to be removed, but you want enough so that there is a gap on the ceramics which will eliminate any leakage current. The picture below shows the results after a few minutes of cleaning. Not very pretty, bit it does restore functionality.

Install a new filament set and you are good to go!  RBD Instruments sells ion gauge filaments for the PHI DGCIII controller.  Contact us for more information.

“A” Numbers for PHI units

Older PHI surface analysis systems use an A number for all the various power supplies that are part of a particular system.  I have no idea what the A stands for.  Below is a list of the A numbers for some of the PHI units.  I plan on expanding this list as more information becomes available.

The A numbers can be useful if you find a cable but do not know where it connects to.  If there is a label on the cable the A number can at least get you to the right unit.

Model numberDescriptionA number
96 AV/F preampA76
ABS selectABS/Heater select boxA114
AVCAuto valve controlA118
BoostivacIon pump controlA218
Bulk HeadBulk head panelA112
CMA/MCDDeflection DividerA277
DCGIIIIon gauge controlA47
DIGITEL 500Ion Pump ControlA137
E.C.L. PSAmp disc power supplyA259
Filter BiasSIMS multiplier filterA139
Power Dist.Fuse stripA143-2
Neut. Defl.Neutralizer deflection boxA223
Oven/PneumaticAir and power distributionA117
SPEC PSSpecialty power supplyA143-1
RF PSRF Generator power supplyA284
Vid MonVideo monitorA152
1182Amplifier discriminatorA236
11-065Ion Gun ControlA4
16-020Heat exchangerA78
16-050Heat exchangerA282
18-180Electron gun controlA268
20-020Heater controlA183
20-028AHeater controlA114
20-320Electron gun controlA159
20-327Electron gun controlA210
20-610Bertan HV supplyA71
20-622Electron gun controlA193
22-040X-ray source HV supplyA160
250MCD preampA250
257Interface boardA258
32-096X-ray source controlA79
32-096X-ray source controlA79
45-300Electronic consoleA194
71-205Motor control boardA127
72-030Neutralizer controlA191
   
74-062Digital Storage MonitorA188
72-250PSD supplyA141
74-500DASH electronicsA252
72-100Electron multiplier supplyA123
72-150AES analyzer controlA128
72-360Small area lens boardA167
72-700SIMS Quad ControlA283
73-057SIMS analyzer controlA139
77-067Ion Gun ControlA125
77-072DP scanning controlA230
79-170Scanning ElectronicsA186
81-175Scanning ElectronicsA187
80-360Analyzer ControlA124