The 20-610 Electron Gun Supply provides the electron beam high voltage for the PHI 600 and 660 scanning Auger systems.  As part of the energy linearity and elastic peak calibration, R108 on the high voltage control board in the 20-610 must be adjusted.  To adjust R108 the 20-610 needs to be pulled out of the electronics rack and the cover needs to be removed to gain access to R108.  This blog post shows how to install a modification to the 20-610 that allows R108 to be adjusted from the front panel without needing to pull out the unit or remove the cover from the 20-610 unit.

Parts needed:

3 pin male and female micro pin connectors (available at Digikey, Amazon, eBay…)

5k ohm 10 turn precision panel mount potentiometer

Vernier dial with lock

3 feet of thin wire 24 to 30 AWG)

Solder and heat shrink

Soldering iron and solder sucker or copper braid

Procedure –

Make sure that the 20-610 electron gun supply is turned off and unplugged.

Remove the 20-610 from the electronics rack. You will need to remove the large high voltage cable and the small Remote Programming connector.

Remove the cover from the 20-610

In the space between the power switch and the Beam Voltage meter find a spot that is centered and drill a 5/16″ hole using a stepper drill. Make sure that the potentiometer will clear the Beam Voltage meter and the power switch -measure twice!

Prep the 3 pin connectors by soldering wires to each pin and using heat shrink to insulate the exposed pins. The wires should be about 6″ to 8″ in length.  The purpose of the connectors is to be able to separate the 100 Control board from the front panel potentiometer in case the 100-control board ever has a problem and needs to be removed to troubleshooting.

Solder 3 of the wires on either connector to the potentiometer. The order of the wires does not matter at this point.

Mount the 5k ohm potentiometer to the front panel using the vernier dial.

Remove the 100 board from the 20-610 and unsolder R108

Solder the remaining 3 wires to the R108 thru holes on the 100 board.  The outside two wires do not need to be in any particular place, but the wiper on the new 5k ohm potentiometer needs to into the center hole on the old R108 location.

Measure the resistance on the old R108 and adjust the new panel mount R108 so that it has the same resistance as the old one.

Route the wires so that they are out of the way and then replace the cover on the 20-610 and reinstall it in the electronics rack. Plug the high voltage cable (push it in all the way and then screw down the collar), install the Remote Programing connector (it lines up like a V) and the power cord.

You are now ready to calibrate the AES linearity and elastic peak position –

Auger energy calibration on 600 and 660 scanning Auger systems

This procedure requires sliding the 20-610 high voltage supply out and removing the cover to gain access to the beam voltage offset potentiometer, R108. Turn off the 20-610 when sliding it in out or in, and when removing or installing the cover.

Procedure:

1. Load a sample of pure copper.

2. If you are using AugerMap software, set the magnification to 10,000X and use the Area Scan mode to minimize sample topography effect on the Auger signal.

3. Perform an elastic peak alignment and adjust the Z axis sample position to obtain maximum counts and best peak shape.

4. Sputter the sample clean until no carbon or oxygen is present.

5. Re-acquire the elastic peak to ensure that the sample is at the optimum position: highest counts and best peak shape. When the elastic peak is differentiated, the positive and negative excursions should be equal and symmetrical.

6. From this point on, do not move the sample!

7. With the beam voltage at 3kV, acquire a survey from 30eV to 1030eV, using .5eV/step, 50 ms/point.

8. Differentiate the survey and check the peak positions against the correct values as listed in the PHI handbook or other reference. A typical value is 920eV for the high energy peak and 60eV for the low energy peak on copper.

9. Note: If using AugerScan software, you can simply adjust the scale factor in the AES Hardware Properties dialog box rather than adjusting the 32-150. If necessary, adjust R58/G3 (AES fine gain) and adjust R61/H3 (AES coarse gain) for proper peak position on the high energy peak. You can acquire an alignment with a range of 900 to 940, .5eV/step, 15ms/point and do the adjustment in real time. For copper, set the n/e peak to approximately 917eV. When differentiated, the high energy Cu peak should be 920eV.

10. Acquire another survey and check that the differentiated peak positions are correct. Document the results for future reference and file it in the system calibration log.

11. Acquire another elastic peak, but do not move the sample!

12. If the elastic peak is not centered at 3kV, then adjust R108 in the Bertan 20-610 High Voltage power supply to center the elastic peak.  If you do not have enough range on the R108 potentiometer you can change R107 and R109 as shown in this blog post – https://www.rbdinstruments.com/blog/20-610-3kv-adjustment/

Calibration is complete.

From this point on, every time you set the elastic peak, the sample will be at the focal point of the analyzer (maximum signal and best shaped peak), and all of the Auger peaks will be in the correct positions.