Auger spectrometer

AUGER SPECTROMETER

June 12, 2000

Directions for using the Auger spectrometer at the soft-landing set-up.

Put the crystal in the target holder of the flow cryostat. Move the target up. At the correct position, the bayonet of the bayonet catch is precisely centred with respect to the CMA.
Move the CMA to ~5 mm from the crystal surface.
Switch the input of the current integrator to ground.

Switch Olivetti M24 on.
Start programm CONTROL by typing the following commands:
```
    cd \cntr
    control
```
Switch BIN crate on.
On the timing filter amplifier (TFA), select integration time '100 ns', differentiation time '100 ns', and set the amplification to the maximum value.
Turn the lower-level of the constant-fraction discriminator (CFD) to the minimum value.

Connect the output of the electron gun to input filt of the CMA.
Connect output entrees balayage to input defl of the CMA.
Connect output foc. to input foc of the CMA. Terminate output grill with 50 ohm.
Connect output analyser modulated hv to the multimeter.
Connect output programmed hv to input cyl ext of the CMA.
Connect the 10 kV high-voltage supply to the multiplier.
Connect the energy output of the multiplier to the input of the pre-amplifier, connect the output of the pre-amplifier to the input of the TFA, and power the pre-amplifier from the rear of the TFA (9-pins D plug).
Connect the output of the TFA to the input of the CFD via an oscilloscope.
Connect DAC 0 to the '100V' input of the KEPCO.
Connect the TTL output of the CFD to logic gate in (terminate the coax cabel with 50 ohm at the input of the gate), connect logic gate out to sca 0, and connect clk on to ext gate. Put the gate switch in position ext.

Switch filament stabilisation to Ie. Turn emission to zero. Set switch in position AES. Turn primary high voltage to zero.
Switch 220 V on with the green toggle switch. Switch the high voltage on with the red toggle switch on the left side.
Select measuring point Ep. Turn the high voltage to -3.0 kV.
Select measuring point filament and CHECK WHETHER EMISSION IS ZERO. Switch filament supply on with the red toggle switch on the right side. CAREFULLY increase the emission to 1.8 A.

Turn the high voltage to zero.
Switch 220 V on with the red toggle switch. Switch the high voltage on with the white toggle switch.
Turn the high voltage to +3.5 kV.

Switch 220 V on with the green toggle switch. Switch the high voltage on with the red toggle switch.
Select measuring point Ecma. Wait half a minute before turning the scan voltage to -1500 V.
Look for pulses on the oscilloscope.

To import the proper CONTROL settings,type command
```
    xct set_aes\ep
```
Check whether DAC0 is connected to the '100V' input of the KEPCO. Turn the scan voltage to 2950 V.
Start the measurement by typing command
```
    sin
```
Use key F10 to toggle from alpha-numeric to graphics display mode. Display spectrum by typing command
```
    ldis 0 0 50
```
Move 'marker 3' to the right spectrum using the keys UpArrow/DnArrow. Move 'marker 3' to channel #25 using the keys LftArrow/RgtArrow.
Adjust the position of the CMA until the primary peak is in channel #25. Optimize the peak shape by varying the voltages of x and y deflections, Wehnelt and focus.

To import the proper CONTROL settingsype, type command
```
    xct set_aes\1000
```
Connect DAC0 to the '1000V' input of the KEPCO.
Adjust the emission current such that the counting rate is < 10⁵ counts/s at a scan voltage of 1000 V.
Turn the scan voltage to zero.
Reset the spectrum by typing command
```
    res 0
```
and start the measurement with
```
    sin
```
Stop the measurement gracefully with command
```
    set swp 1
```
Data acquisition will stop at the end of the current scan.

Calculate the derivative dN/dE by typing command
```
    diff 0 1 smooth
```
Larger values of parameter smooth improve statistics, but increase the line width. In general 10 is a good choice.
Display the result with command
```
    ldis 1 1 scl -100 100
```
Adjust the scale with the keys +/-.
CONTROL command
```
    auger
```
will do the rest. For further details, type
```
    help auger
```

Open a new data file by typing command
```
    open 1 auger/run nnn
```
where nnn is a new unique identification number.
Write nnn plus details of the sample in the Auger lab-book.
Reset run number with command
```
    run 1 label
```
where label is a brief description of the sample (e.g. InCu(001)).
Write spectrum to disk with command
```
    wrt 0 2
```
Eventually, transfer Auger spectrum to the unix cluster for archiving.