LS intro and LS stage notes

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This post is a compilation of notes that I have on the LS (large sample) intro and specimen stage used on older PHI 5400 and 5600 LS systems.

To Replace the LS Intro Ribbon:
First remove the 4 screws that hold the ribbon tape to the stage dock slider. These would be the back 4 screws (towards the feed-thru).
Remove the LS feed-thru knob.
Remove the LS ribbon feed assembly (about 8 7/16” bolts) and pull it straight back.
Loosen the 3 screws that provide tension to the wheel by backing them out all the way.
Remove the 4 screws that hold the screw assembly in place and remove the screw assembly.
The old ribbon can be removed (2 screws compress the slot).
Spin the wheel in the direction that the tape would go into the system until the wheel stops. This is the Fully In position.
Put the new tape into the LS intro slot and attach it to the stage dock slider. Make sure that the slider can move in and out smoothly. Adjust the slider if needed until the motion is as friction free as possible.
Remove the 4 screws and pull the tape out of the LS intro.
Install the new tape to the wheel in the Fully In position. Tighten the 2 screws to compress the wheel and hold the tape.
Re-install the screw assembly and tighten the 4 screws that hold it in place.
Tighten the 3 screws by turning them in finger tight until there is a reasonable amount of tension on the wheel. There needs to be enough tension to hold the tape and spin it onto the wheel, but not so much as to make the wheel hard to turn.
Wind the tape onto the wheel by spinning the wheel backwards. Guide the tape onto the wheel so that it goes on straight. Keep about 6 inches of the tape out.
Replace the LS ribbon feed assembly and gently guide the tape into the slot.
Attach the LS ribbon feed assembly with 2 bolts just to hold it in place for now.
Reconnect the 4 screws and attach the tape to the stage dock slider.
Insert a screw driver into the feed-thru port and verify that the tape and stage dock slider move smoothly. Adjust if needed.
Connect the rest of the 7/16” bolts to the LS ribbon feed assembly and tighten all of the bolts. The seal is made with a Viton O-ring.
Use a new 1.33″ copper gasket and attach the feed-thru knob.
Verify that the ribbon moves easily and smoothly. If not, remove and inspect.
Installation Complete!

Adjusting the stage to the DOCK, LOAD and Bake-out positions.

The Bake-out position is set to values where the stage has minimum load on all of the axis and cannot be changed. It is very important to set the stage to the bake-out position before removing the motors. If you take the motors off when the stage is not set to the bake-out position, serious damage to the stage can occur.
The nominal values are listed below for DOCK, LOAD, Home and Bake-out. DOCK and
LOAD need to be set to line up with the LS intro ribbon. Home is set to a central location of the stage that it at the focal point of the analyzer.
It is very difficult to line up the stage to the DOCK and LOAD positions when the system is under vacuum due to the limited visibility of the LS chamber.
So, if you cannot get it to line up by making small adjustments to the Y, rotation and Z axis, then you will need to vent so that you can use a mirror and look down the intro into the system. When the system is up to air this is very easy to do.
Notes:
You can fine tune the Y axis by removing the motor and manually centering the Y axis of the stage to line up with the LS intro ribbon. Then, set the Y axis motor to zero (0) mm and put the motor back on the Y axis stage micrometer.

Notes on the LS Stage (30-520) Operation

Warnings!
*********

Great care must be taken during the operation of this stage.
Careless operation can easily result in damage to the stage and/or
vacuum system components. If you consider that the stage
mechanism is sensitive, common sense dictates that you must observe
every motion carefully, and THINK before clicking a stage control
button and entering position parameter values. Loading and
unloading the platen are especially critical.

Stage Motion
************

The stage may be moved by either adjusting a particular position
parameter individually, or selecting one of the preset positions.
The preset position selection will adjust all position parameters
accordingly.

Each of the stage motion parameters (X, Y, Z, Tilt, and Rotate)
may be adjusted individually in two ways.
(1) By selecting the “Adjust” button
next to the parameter, the stage will track the indicated
position as you scroll it with the up/down arrows. This generally
is the safest method for moving the stage when the platen is
close to objects (x-ray source, analyzer nose, etc.) in the
chamber. However, it takes much longer to move long distances.
(2) By typing in the desired parameter position(s), then clicking
on “Set” for one particular position parameter, or “Set All” for
all position parameters simultaneously. the stage will move
directly to that position.
This is the fastest method for moving to a custom position, but
is also the most dangerous if the typed value(s) was
inappropriate considering any obstacles in that motion path.

The stage may also be moved to one of four preset positions.
Three (Dock, Load, and Home)
may be reset by the operator and the fourth (Bake) is set to a
predefined position and cannot be reset. They are described
as follows:

Preset Positions
1. “Dock” – puts the stage in position for sliding the platen on
or off of the stage itself from the intro chamber.
2. “Load” – raises the stage slightly from the “Dock” position so
that the intro ribbon may be disengaged
3. “Home” – a user defined position, usually used to move back to
a particular area currently under analysis. This
position may be redefined whenever desired.
4. “Bakeout” – moves the stage to the position where all tension-
ing springs are “de-energized”. The stage must be
moved to this position before removing the motors,
such as just before a bakeout.

When moving the stage with obstacles nearby and you are unsure of
the clearances, watch and be ready to click on the “Stop” button
to halt the motion of the stage.

To reset the “Dock”, “Load” or “Home” positions, simply move to the
desired stage position that you wish to reset it to, then click on
the “Reset (position)” button. It would be a very good idea to
note the original settings of “Dock” and “Load” before resetting
them, so that you can return to them if problems arise later with
the new reset position.

Transferring the platen
***********************

1. To transfer the platen from the intro chamber to the stage:
a) Set the stage to the “Dock” position.
b) Extend the intro ribbon until the platen is docked on
the stage. The proper position can be felt by
the engaging of a detent on the stage. The
platen will extend out both ends of the stage
by equal distances.
c) Carefully, select the “Load” position. This will
increase the Z axis slightly so that the ribbon
can release.
d) Withdraw the intro ribbon.

2. To transfer the platen from the stage to the intro chamber:
a) Set the stage to the “Dock” position.
b) Extend the intro ribbon until it engages the platen.
c) Start to withdraw the ribbon. The platen should follow.
d) Continue until the platen is in the intro chamber.

Operating Cautions and Hints
****************************

1. Always watch the platen and stage carefully through the view
ports during transfers.
2. If the platen stops moving, or disengages the ribbon during
the withdrawal, before the completion of the transfer,
attempt to move the platen back to the original position.
Then make a slight adjustment to one of the position
parameters (with the Adjust feature) and try again.
3. Be very cautious when making adjustments to the position
parameters when the ribbon is extended to the platen
and/or the platen is half on/off the stage. Make only
slight adjustments!

Amplifier Discriminator Tests

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One of the troubleshooting techniques that can be used to test the counting circuitry of an auger or XPS system is called “tickling the brick”.   The term came about from when the early PHI systems used the Princeton Applied Research (PAR) 1120 amplifier discriminator for pulse count detection of electrons. The 1120 kind of looked like a brick, and so the term “tickling the brick” was born.

Basically, tickling the brick tests the brick (amplifier discriminator) and the counting circuitry.   This is one of the first troubleshooting steps that you would take if you are not getting any counts at all with your auger, XPS or SIMS system.

The 1120 amplifier discriminator is still in use on many PHI systems, as is its newer replacement, the 1182.  The 1120 and 1182 are used with single channel detectors.

In addition to the 1120 and 1182 amplifier discriminators, the “tickling the brick” concept can also be applied to PSD and MCD detectors on XPS systems.

The procedures for each amplifier discriminator type are described below.

Amplifier-Discriminator

1120/1182 Test Procedure

  1. Set up a alignment (can be any range) and select the 1120/1182 as the signal input. For most PHI systems using AugerScan software, that will be PC1 input in the hardware properties dialog box.
  2. Remove the bnc input that goes between the analyzer and the 1120/1182
  3. Turn off the analyzer control and electron multiplier supply as they are not needed.
  4. Start the alignment acquisition and then stick a piece of wire into the bnc input of the 1120/1182. This wire will act like an antenna and you should see between 20 million and 30 million CPS of noise.
  5. Remove the wire and the counts should go to zero.

If the counts behave as expected then both the 1120/1182 and the counting circuitry are working properly.

PSD Position Sensitive Detector Preamp Test Procedure

PSD

PSD

 

 

 

 

 

 

 

 

  1. Set up an alignment (can be any range) and select the PSD as the signal input. For most PHI systems using AugerScan software, that will be the PSD input in the hardware properties dialog box.
  2. Turn the card rack power OFF.
  3. Remove the bnc inputs to the PSD that goe between the analyzer and the PSD. These are the little white wires that go from Preamps A and B to the analyzer.
  4. Connect a test clip to the center pins of each of the little white wire bnc connectors.
  5. Start the alignment acquisition and then with your fingers touch the ends of both of the test clips that go to the center pins of each of the little white wire bnc connectors. The test clips will act like an antennae and you should see about 50K to 80K CPS of noise. Both clips need to be touched at the same time. NOTE: The clips go to the wires, not the BNC connectors on the analyzer.
  6. Remove the test clips and the counts should go to zero.

If the counts behave as expected then both the PSD preamp and the counting circuitry are working properly.

Make sure that the card rack power is OFF when you reconnect the PSD cables to the analyzer.

MCD Amplifier/Discriminator Test Procedure.

MCD

MCD

 

 

 

 

 

 

  1. Set up an alignment (can be any range) and select the MCD as the signal input. For most PHI systems using AugerScan software, that will be the MCD input in the XPS hardware properties dialog box.
  2. Turn the card rack power OFF.
  3. Unscrew the MCD amplifier discriminator from the analyzer flange and carefully remove it. NOTE: Use care when reinstalling it after the test procedure to make sure you do not bend any pins. Also make sure that the card rack power is OFF when you reinstall the amplifier discriminator on the analyzer flange
  4. Turn on the card rack power and start the alignment.
  5. There are 20 socket connectors visible on the end of the MCD amplifier discriminator. Each of those connectors (except for the middle 4) represents one of the 16 channels that are connected to the MCD detector inside the analyzer.
  6. Start the alignment acquisition and then stick a wire into each of the open pins on the end of the MCD preamp, one at a time. The test clips will act like an antennae and you should see about 20K to 80K CPS of noise when the clip is inserted.
  7. Remove the wire and the counts should go to zero.
  8. Repeat steps 6 and 7 for each of the other pins on the end of the MCD amplifier discriminator.

If the counts behave as expected then both the MCD amplifier/discriminator and the counting circuitry are working properly.

BCF Database for AES

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Version 1.0 of the Backscattering-Correction-Factor Database for Auger Electron Spectroscopy program provided by NIST provides BSFs of homogeneous materials.

From the NIST website: This database provides values of backscattering correction factors (BCF) of homogeneous materials for quantitative surface analyses by Auger electron spectroscopy (AES). These BCFs are obtained from Monte Carlo simulations based on two models of electron transport in the material, a simplified model and an advanced model. One assumption for the former model is that the primary-electron beam is unchanged, in intensity, energy or direction, within the information depth for Auger-electron emission. This assumption becomes progressively less useful as the primary energy becomes closer to the core-level ionization energy for the relevant Auger transition or for increasing angles of incidence of the primary electrons.

BCFs can be calculated from both models so that users can readily ascertain the magnitudes of differences in BCFs from each model for materials and analysis conditions of interest. Analysts can readily specify the experimental conditions of interest (primary-beam energy, primary-beam angle of incidence, and, for the advanced model, analyzer-acceptance solid angle), the likely or estimated sample composition, the subshell of the element to be ionized, one of three available formulae for the inner-shell ionization cross section, and, for the advanced model, the Auger-electron transition of interest. The user can also select different numbers of trajectories in the Monte Carlo simulations so that tradeoffs can be made between calculation time and precision of the resulting BCF value. While simulations with the simplified model are generally faster than those with the advanced model, BCFs from the advanced model are considered more reliable. The results of a BCF calculation can be stored in a file for later use.

System Requirements: Personal computer operating on Windows 95, 98, NT, 2000, ME, XP, Vista, or 7, and hard disc space of at least 50 MB.System

Price: No Charge

You can download the program here – https://www-s.nist.gov/srd_online/index.cfm?fuseaction=home.main&productID=SRD154