XPS Info - Issues

This page describes some of the technical issues we've run into and how they were solved:

The turbo pump of the analysis chamber should always be on so if it is off there is a problem.

One reason for this to happen can be that if the valve (V4) between the turbo pump and the backing pump doesn't open, sometime after loading a sample, the pressure inside the analysis chamber may increase. If the pressure becomes too high, the PLC will shut down the turbo pump as a safety measure... The reason for the valve not to open can be the pressure of the compressed air being too low. This should be set to 4.5 bar.

In any case notify the technician, because this is a serious issue and as a side effect the communication with the detector may be lost...

There are several possible reasons why the autoheight function might fail.

One reason is a bit trivial. In that case the stage runs into one of its limits. Setting the right starting point and range of operation will avoid this situation. The maximum height that can be reached is 38 mm.

Another reason is also a bit trivial. If the flood gun isn't being used and the sample is a good insulator, then the autoheight function runs as expected but at the end either goes to the wrong height or halts the experiment. The reason is that in that case the signal is shifted to (much) higher binding energies and the oxygen peak, commonly measured during the autoheight procedure, cannot properly be meaured.

Yet another reason is more serious. In that case the stage moves up and down exactly as expected, but after the final step the program stops (with an error). The most probable cause is that the communication with the detector fails, in which case the assistance of the technician (to reset the XPS) is required.

If one suspects that the top camera in the analysis chamber is misaligned, e.g. that the point of measurement doesn't coincide with the location of the X-ray spot, then there is a simple trick to establish this.

On the top-left of the 'Optical View' page select the pre defined position 'Phosphor'. Press the arrow to move there. Turn the internal lights off. Open the X-ray control dialog from the diagram on the 'Sample' page. Turn on the X-ray gun. Allmost immediately the X-ray spot will light up.

If the X-ray spot isn't at the center of the image then the camera is misaligned. Until this has been solved by the service engineer, the XPS can still be used but one should take into account that there is an offset (either horizontally or vertically or in both directions).

If one of the cameras is off, or rather not working, then, in most of the cases, the quickest way to turn it back on is applying the following procedure:

  • close the Avantage software
  • run the server stopper program
  • run the search device program and perform a search for devices
  • start the Avantage program
  • check the result

If this still doesn't work, then run the first two steps and then detach the camera for 10 seconds. After that run the remaining steps. The cameras can be reached by removing (lifting and pulling) the cover with the LEDs.

At this point the cameras, or just one camera, can still be missing. Check the video channels list to see whether or not all camera have been properly assigned. The correct assignment is:

Sample View : DFx41AF02
Height Adjust: DFx21AF04#2
Tranfer View: DFx21AF04

The video channels list can be found by the following sequence of choices:

- Preferences
-- UI Preferences
--- Optical/Platter View
---- Optical View
----- Video Channels

In charging an insulated sample isn't properly compensated then all peaks will become broader (and lower) than expected, or all peaks may appear at two positions due to differential charging.

One way, in general, to prevent this issue, is to make sure that the sample is properly connected to the sample holder. For example if a clamp is used to fixate the sample, then put it close to the point of interest.

If the peak broadening or peak doubling appears on multiple samples, then it is worthwhile to try to optimize the flood gun.

While an experiment is running the flood gun control program can be openened, for example by clicking the flood gun LED on the task bar or by clicking on 'Flood Gun' on the sample page.

An expert user (normal situation) can change the X Shift and Y Shift voltages that control the position of flood gun. These voltages can be used to optimize the collected current. In engineering mode also the Focus votage and the Gas Cell voltage can be changed in order to optimize the collected current.

While changing the voltage the effect can be followed in an experiment e.g. a C1s Snap measurement within an iteration.

If Avantage reports that the sampleblock isn't on the stage and leaves the transfer arm extended, then there may be a serious problem. If this happens for the first time, then it can be tried to place the sampleblock back into the park position after which the sampleblock can be moved onto the stage again.

If the option to move the sampleblock to the park position would also pressurize the loadlock, then first use the option to move the sampleblock onto the stage. The system then oddly enough reports that the sampleblock is already on the stage, but after this it should be possible to put the sampleblock in park mode without pressurizing.

If Avantage doesn't allow to retract the transfer arm, then it can still be tried through the 'Vacuum Details' program. This is a program that can be started via the button on the 'Sample' page in Avantage, but also via the shortcut on the taskbar.

If the error persists the help of the service engineer may be required. In any case report the error to the technician.

The vacuum in the loadlock should be below 2*10-7 mbar before a sample can be moved into the analysis chamber. There can be several reasons why this level can't be reached. Common reasons are: too many samples, some grease on the hatch, a hair on the O-ring etc. If it is obvious what is the cause, it is also obvious what is the solution. Sometimes it is necessary to repeat an action and since it takes quite some time to get to the right vacuum level it is advised to pay special attention performing such an action; take away not one but a few samples if there are too many samples, clean the hatch a few times if that seems to be required and doublecheck the O-ring if you've discovered a hair.

The vacuum in the analysis chamber should be 5*10-8 mbar or less. If the vacuum is too high it could be resolved by moving the sample holder into the analysis chamber or by opening the bypass valve, valve V3. Valve V3 can't be controlled directly, but by turning on the flood gun it will be opened. Shutting down the flood gun again will keep valve V3 open!

If it seems that the vacuum gets better and better, then it may be a forewarning of a failing sensor. If the sensor of the loadlock fails, it can be replaced by the technician. If the sensor of the analysis chamber fails, it has to be replaced by the service engineer.

XPS info / ChemE / Delft University of Technology
version 20221117
anything else...
© 2000 - 2023 All rights reserved.
Design by Bb.