PCMAPII support has ended.

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As of January 1st, 2022, RBD Instruments has discontinued support for our PCMAPII interface boards used on legacy PHI / Perkin-Elmer scanning auger electron spectrometer systems such as the model 590 and 600. 

This blog post lists all of the documentation related to the PCMAPII interface board.  If your PCMAPII board develops a problem and this documentation does not help, please contact RBD Instruments for other options.

The links below will open up PDF files that you can view and print.

PCMAPII Installation, testing and calibration

PCMAPII Schematics

PCMAPII Summary

PCMAPII Ground jumpers

PCMAPII Jumper Rotation

PCMAPII Video buffer detail

SCA charging lens elements

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This blog will describe the symptoms and solution for lens elements that charge up due to an oxidized graphite coating.

Overview – The Physical Electronics SCA (Spherical Capaitive Analyzer) has a series of 2 or 4 lenses that focus electrons into the energy analyzer section of the SCA. The first two lenses determine the analysis area and the second two lenses focus the electrons into the SCA for optimal counts and energy resolution. The voltages applied to the lenses change as a function of the kinetic energy of the electrons being detected. The sketch below shows the general concept on an SCA that uses a Position Sensitive Detector. Most SCAs today have a MCD multi-channel detector but the lenses work the same way.

SCA Lens Concept

The 5600 XPS system lenses are constructed out of stainless steel. In order to reduce the secondary electron yield (a lower secondary electron yeild improves energy resolution), Aquadag is sprayed on the inside of the lens surfaces. Aquadag is basically pure carbon, and carbon has a low secondary electron yield.

Problem – unstable data at higher pass energies, larger analysis areas, or higher x-ray source power.

Normally charging presents itself as unstable data with very high spikes in the counts followed by rapid discharges. In this case, the problem presented itself more like a digital step problem with very repeatable steps in the data at particular eVs. Another interesting effect was the ratio of peak heights would also change as a function of the pass energy, analysis area or x-ray source power.

Initially the symptoms pointed to the MCD multi channel detector or the chevron plates. The MCD was pulled and inspected an no problems were seen. The chevron (channel) plates were replaced and that did not change the symptoms.

Another clue was that if the lens cables were removed from the SCA and the lens elements shorted to ground, the data looked correct. In addition, one lens could be grounded and the other lens could have voltage applied to it and the data would also look correct. However, if the area of one of the the lenses were changed (by selecting large area mode) the problem would return, even with the other lens still grounded.

The conclusion was that the surfaces of the lenses must be charging, but only at large areas where more electrons would fill the lenses.

The SCA lens was removed and the resistivity of the lens elements were measured. The resistance of the lens coating would vary from tens of ohms to thousands of ohms depending on where the measurements were made. These resistance measurements matched the symptoms as a high resistance surface would not conduct the electrons that hit the inside of the lens cylinders.

Aquadag works well to reduce secondary electrons. But if exposed to air for extended periods of time it (evidently) can form an oxide layer which increases the resistance of the coating substantially.

A clean stainless steel scouring pad with a very light touch was used to break the oxide layer without removing too much of the Aquadag coating.

stainless steel pad

The technique used was to lightly rotate the scouring pad inside the lens elements and then check the resistance of the lens coating. The resistance would gradually drop with each rotation of the scouring pad. When the resistance dropped close to a few ohms, no further scouring was done.

Lens element

When this process was completed, the inside of the lens elements were conductive but still black, so most of the Aquadag coating was still intact.

After reinstalling the lens, pumping down and baking the vacuum chamber, the SCA performed correctly.

The first step is to remove the bolts on the flange that hold the lens to the chamber. Then, tilt the SCA back so that it rests on the arm stop. Remove the aperture size knob and the two lens feedthroughs. Next remove the nipple. Then, remove the magnetic shield (4 long screws) and finally the lens assembly (2 screws).
Once the lens assembly is out you need to separate all of the sections in order to be able to use the scouring pad. The lens sections are held in place with screws and ceramics.
Close up of lens electrical contacts. The top one has been removed by unscrewing the rod CCW.

If you are experiencing this problem please contact RBD Instruments for more details.

80-365 analyzer control notes

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This blog post is a compilation of notes which are helpful when troubleshooting or calibrating the 80-365 (and 80-366) SCA analyzer control.

The 80-365 SCA analyzer control provides all of the voltages to the SCA (spherical capacitive analyzer) used on older PHI XPS (X-ray photoelectron spectroscopy) systems. Those include the retard voltage, the pass energy, the lens voltages and the electron multiplier voltage.

To troubleshoot or calibrate the 80-365, follow the calibration procedure in the 80-365 manual. Note that high voltages are present on the 80-365 boards, always refer these types of measurements to technicians who have been properly trained in working with high voltage!

If are unable to repair the 80-365 yourself, please contact RBD Instruments and we can repair the boards for you.

80-365/66 Lens Board DAC bit test

To test individual bits:  Write out on DR11 A CSR 1   

Note:   Write the low order byte out first, then the high order byte. If you get out of sequence you need to turn off the card rack power to reset the board and start over.

Lens 2

Measure from the left side of R62 to the right side of R94/G4

BitLow byteHigh byteDAC voltage
0160016000.0000
1160216000.0012
2160416000.0024
3160616000.0049
4161016000.0098
5162016000.0195
6164016000.0391
7168016000.0781
8160016010.1563
9160016020.3125
10160016040.6250
11160016081.250
12160016102.500
13160016205.00
1416FF163F10.00

Lens 3

Measure from the right side of R70 to the right side of R94/G4

BitLow byteHigh byteDAC voltage
0180018000.0000
1180218000.0012
2180418000.0024
3180618000.0049
4181018000.0098
5182018000.0195
6184018000.0391
7188018000.0781
8180018010.1563
9180018020.3125
10180018040.6250
11180018081.250
12180018102.500
13180018205.00
1418FF183F10.00

80-365 Lens board calibration notes

For XPS and AES, the output voltages are positive, and the fine supplies are negative.  Make sure that you set the polarity before programming on dual polarity boards.

1310 is + polarity for L3

1320 is + polarity for L2

Common data values

L2            Output C53/G5                  Fine Supply    – lead ground side R143   + lead right side R142/G5

1801,1800 – Adjust R45/A3 for -20V on fine supply

1800, 1808 – Adjust R77/B4 for – 20V on fine supply           Adjust R67/G3 for +409.6V on C53

18D4, 1830 – Adjust R67/G3 for +2500.0 V on C 53 output.  Readjust R77/B4 for -20V on fine supply

1800, 1800 – zero

L3            Output C41/E5                   Fine supply         – lead ground side R127/E5  + lead left side R120/E5

1601, 1600 – Adjust R52/C3 for -20V on fine supply

1600,1608 – Adjust R87/D4 for–20V on fine supply      Adjust R59/E3 for +409.6V on C41

16D4, 1630 – Adjust R59/E3 for +2500.0V on C 41 output. Readjust R87/D4 for -20V on fine supply

1600,1600 – Zero

NOTE:    If you have issues with the +5V supply dropping and voltages not loading properly, look at the local power supply board.  You may need to replace the 3524 regulator on the local power supply board.

80-365/66 Pass Energy board DAC bit test

To test individual bits:

Pass energy range = is 0 to 10V on the DAC = 1920 or 2145 depending on the model number of your analyzer control.

Write out on DR11 A CSR 1   

Note:  Write the low order byte out first, then the high order byte. If you get out of sequence you need to turn off the card rack power to reset the board and start over.

To set the DAC back to zero between bits, write out 1a00 twice

The following table shows the voltage on the DAC measured from TP24 / C2 to TP24B /C2  

0000 0000 0000 0001

bit 0

0.022 V

1a01, 1a00 = .0001525 V on the DAC

0000 00000000 0010

bit 1

.044 V

1a02, 1a00 = .0003052 V on DAC

00000 0000 000 0100

bit 2

.088 V

1a04, 1a00 = .000 6V on DAC

0000 0000 0000 1000

bit 3

.019 V

1a08, 1a00 = .00122 V on DAC

0000 0000 0001 0000

bit 4

0.35 V

1a10, 1a00 = .00244 V on DAC

0000 0000 0010 0000

bit 5

0.7 V

1a20, 1a00 =.00488 V on DAC

0000 0000 0100 0000

bit 6

1.4 V

1a40, 1a00 = .0097 V on DAC

0000 0000 1000 0000

bit 7

2.8 V

1a80, 1a00 =.019 V on DAC

0000 0001 0000 0000

bit 8

5.63 V

1a00, 1a01  =.039 V on DAC

0000 0010 0000 0000

bit 9

11.25 V

1a00 ,1a02  = .078 V on DAC

0000 0100 0000 0000

bit 10

22.5 V

1a00 ,1a04  = .156 V on DAC

0000 1000 0000 0000

bit 11

45 V

1a00 ,1a08   = .3125 V on DAC

0001 0000 0000 0000

bit 12

90.02 V

1a00 ,1a10  = .625 V on DAC

0010 0000 0000 0000

bit 13

180.03 V

1a00,1a20   =1.25 V on DAC

0100 0000 0000 0000

bit 14

360.06 V

1a00 ,1a40   = 2.5 V on DAC

1000 0000 0000 0000

bit 15

720.13 V

1a00 ,1a80  = 5.0 V on DAC

All Bits:

1A00, ,1aFF   = 10 V on DAC

1920 or 2145 VDC on the output across C56

80-365 / 366 Pass energy board range note

The 80-365 and 80-366 pass energies have different maximums.

The 80-365 is 1920V

The 80-366 is 2145V

Make sure that you have the correct procedure when you calibrate the board.

Measuring the Pass Energy output voltages

There are some scale factors involved when measuring the pass energy voltages.   

If you are measuring the pass energy voltage across C56 on the pass energy board, the scale factor is approximately X 1.34.  For example, if you set the pass energy to 187.85, the output voltage across C56 is 187.85 X 1.34 = 251.8 VDC.   You can calculate any pass energy actual voltage value by multiplying the pass energy in the software (set up an alignment or survey) by 1.34.

If you are measuring the test points in the filter box, the scale factor is to divide by 1.7.    For example, a pass energy of 187.5 divided by 1.7 = 110.3 VDC.  If you set up the pass energy to 187.5 in the software, you will see approximately 110.3 VDC between the IC and OC test points in the filter box. The resistors in the filter box divide the voltages so that they are correct on the IC, OC and MR contacts in the analyzer.

To summarize –

C56 output on pass energy board = Pass Energy X 1.34

Test points in filter box = Pass Energy divided by 1.7

80-365 Local Power supply board notes

Capacitor Voltage Comments
C33 22V +/1 1.5V   adjust R27 Transformer output before regulator
C35 +15 Pass energy board power
C36 -15 Pass energy board power
C34 +5V Pass energy board power
     
C9 22V +/1 1.5V  adjust R3 Transformer output before regulator
C10 +15 Lens board power
C7 -15V Lens board power
C12 +5V Lens board power
     
CR35 cathode to CR36 anode +225V Pass energy board power
CR 37 anode to CR36 anode -225V Pass energy board power
     
CR17 cathode to CR17 anode +150V
CR18 anode to CR17 anode -150
 

TIP: If the voltages are low when the pass energy or lens boards are installed, most likely the issue is a weak 3524 regulator. Replace it with a new SG3524N

80-365 Retard supply bytes

bitlow byte (hex) hi byte (hex)DAC V
0110012000
1110112000.00015259
2110212000.00030518
3110412000.00061035
4110812000.0012207
5111012000.00244141
6112012000.00488281
7114012000.00976563
8118012000.01953125
9110012010.0390625
10110012020.078125
11110012040.15625
12110012080.3125
13110012100.625
14110012201.25
15110012402.5
16110012805
All11FF12FF10