This post explains some tests and calibrations for the 20-805 analyzer control which is used on older Physical Electronics (PHI) ESCA, XPS and AES surface analysis systems. The 20-805 analyzer control is typically used to control the 15-255G and 25-260 double pass cylindrical mirror analyzers.
20-805 Analog AES Input Test Procedure
This section explains the procedure for testing whether or not the 0 to 10 volt drive signal from the PC137A or RBD147 interface unit is working properly.
Equipment needed: DVM and BNC adaptor cable
The 20-805 has a gain of 200:1 and the analyzer scale factor is 1.7. This means that the ratio between eV detected and the DC voltage applied to the outer cylinder of the analyzer is 1.7 to 1. For example, to measure a 1000eV electron, 588.823 DC volts must be applied to the outer cylinder.
To calculate what the Analog or Input voltage should be for a particular eV, use the following formula:
Analog or Input voltage = eV divided by 1.7 divided by 200.
Example: 2000 eV divided by 1.7 = 1776.47 divided by 200 = 5.8823 volts on the Analog or Input cable.
Procedure:
- Turn the power off on the 20-805 analyzer control.
- Remove the Analog Input cable and connect it to a DVM.
- Set up an elastic peak alignment with a lower limit of 100 and an upper limit of 100. (This will put the sweep voltage at a single fixed value).
- Acquire the alignment and measure the voltage on the Analog or Input cable. The voltage should be about .294 volts DC.
- Set up an elastic peak alignment with a lower limit of 2000 and an upper limit of 2000.
- Acquire the alignment and measure the voltage on the Analog or Input cable. The voltage should be about 5.88 volts DC.
If the Analog or Input voltage is correct, then the D/A on the PC 137A or RBD147 is working properly.
20-805 Pass Energy Supply Test
The 20-805 Pass Energy Supplies provide the proper voltages to the PHI double pass CMA when used in the XPS mode.
To test:
- Short out the Analog Input on the back of the 20-805 with a bnc shorting plug. This will ensure that the high voltage output is zero.
- Set the pass energy switch on the 20-805 to 100.
- Measure between the HV and IC connectors on the back of the 20-805. The voltage there should track the Pass Energy switch on the front panel with-in .5 volts.
- Check that the HV to IC voltage matches the front panel for all pass energy settings.
- Measure between the IC and OC connectors on the back of the 20-805. The voltage there should track the Pass Energy divided by 1.7 on the front panel with-in .5 volts.
- Check that the IC to OC voltage matches the front panel for all passed energy settings.
| Pass Energy Setting | HV to IC voltage | IC to OC voltage |
|
10 |
10 |
5.88 |
|
25 |
25 |
14.7 |
|
50 |
50 |
29.4 |
|
100 |
100 |
58.8 |
|
200 |
200 |
117.64 |
If the voltages are not correct, check the 20-805 Pass Energy Supply capacitors and TIP53 transistors.
The 20-805 gain is 200:1. You can use AugerScan to send out specific voltages on the D/A output (analog input) cable –
1) With the RBD147 on, run AugerScan.
2) Select “Diagnostics” from the “System” menu.
3) At the bottom of the dialog box, make sure the option for “Hexidecimal” is checked.
4) In the Address field for RBD147, enter 10
5) Individually enter the following in the Data field, and hit the Write button for each while checking the 20-805 control voltage:
8000 (0 V)
9FFF (1.25 V)
BFFF (2.5 V)
FFFF (5 V)
7FFF (10 V)
AES Calibration when using a 20-805 Analyzer Control – For a 10-155 or 15-255G Analyzer.
This section explains how to calibrate the AES peak energies and 2 kV elastic peak crossover.
Tools needed: Insulated adjustment screwdriver (pot tweaker)
Copper foil or gasket material.
Procedure:
- Read this entire procedure before starting the calibration.
- Load a sample of copper foil into the system and set the beam voltage on the 11-010 electron gun control to 2kV.
- Position the sample to the focal point of the analyzer using the AES Align routine. At this point it does not need to be exactly at 2kV, just make sure that the peak is maximized.
- Sputter the sample clean. Note: If you do not have a sputter ion gun on your system, then scrape the sample with a razor blade or exacto knife before you load it into the system to remove the surface carbon and oxygen.
- After the sample is clean, re-acquire the elastic peak and re-check that the peak is at maximum counts and beast shape. Do not worry if it is not at 2kV crossover, that will be adjusted later.
- From this point on, DO NOT MOVE THE SAMPLE!
- Acquire an alignment from 900 to 960 eV and differentiate the data. The peak should be at 920 differentiated. If not, adjust the scale factor in the AugerScan Hardware Configuration menu a little bit and re-acquire the alignment and check the position. A large scale factor number will move the peak down in eV.
- Re-peat and adjust the scale factor as necessary until the differentiated copper peak is at 920eV.
- Change the alignment settings to 2kV default and re-acquire the elastic peak. But, DO NOT MOVE THE SAMPLE! If the peak is not at 2kV, then adjust P1 in the 11-010 to move the peak so that it is at 2kV. Caution! There is high voltage present in the 11-010, do not perform this adjustment unless you are qualified to work on high voltage. Refer servicing to qualified personnel.
Location of P1 in the 11-010 Electron Gun Control is shown above.
- Once you have the 11-010 adjusted to 2kV, change the beam voltage to 3kV and acquire a survey from 30eV to 1030eV, 1 eV per step, 50 ms per point, and 3 sweeps.
- When complete, the survey should look like the date below after it is differentiated:
Calibration Complete!
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