Using the CMapp Extended Conditioning Feature for the microCMA

CMapp (software for the microCMA) versions 1.2 and greater now have a feature which allows for extended conditioning of the integrated 3kV electron gun.

To access this feature, first make sure that the Beam Voltage and Filament Current in the Electron Gun Controller are both turned off.

Open the conditioning dialog box by selecting the System / Conditioning… menu command or by pressing the Conditioning Icon on the task bar. Next, follow these steps:

Conditioning Icon
CMapp Conditioning Dialog
CMapp Conditioning Dialog
  1. Check the Filament Degas box and set the time in minutes that you want the filament current to ramp up. For new installations the degas filament current value is imported from the factory properties file and can be set for a time of 60 minutes. After the electron gun has been fully conditioned you can reduce the Filament Degas Time to as short as 5 minutes.

  2. Next check the Beam Conditioning box and set the starting voltage to 0 and the ending voltage to 3000. For new installations this can be set to 120 or 180 minutes. That is how long it will take to bring the beam voltage all the way up. After the electron gun has been fully conditioned you can reduce the Beam Conditioning Time to as short as 5 minutes, but 20 or 30 minutes is the recommended minimum Beam Conditioning Time.

  3. Next check the Filament On box. Checking this will keep the filament on while the beam voltage is being ramped up. This helps to condition the electron gun by letting the heat from the filament keep the electron gun warm.

  4. Make sure that the Multiplier Conditioning box is not checked and then check the Extended Conditioning box. If the Multiplier Condition box is checked then the Extended Conditioning box is grayed out.

  5. With the Extended Conditioning box checked, enter the amount of time that you would like to let the electron gun sit with the filament current on and the beam voltage at 3kV.  Typically, this time is set to 120 to 180 minutes.

  6. Press the Start button and the Conditioning routine will ramp up the filament, then ramp up the beam voltage, then hold the beam voltage at 3000V and keep the filament ON until the time runs down.

The Extended Conditioning feature helps to outgas the electron gun and condition the electron gun ceramics which in turn helps with the stability of the electron beam and data signal to noise.

Learn more about Auger Electron Spectroscopy and RBD’s microCMA.

microCMA Length, the Long and Short of It

RBD Instruments’ microCMA compact Auger electron energy analyzer is designed to fit on a standard 2.75″ / 70 mm CF flange. This makes it possible to add surface sensitive AES (Auger Electron Spectroscopy) to an existing vacuum chamber, as long as there is an available port.

The standard length of the microCMA analyzer is 11.1″ / 283 mm which works well for most 8″ / 200 mm diameter vacuum chambers. This standard length factors in a Z translator that is used to move the microCMA to the sample for analysis and to retract the microCMA when it is not in use. 

However, what if your flange-to-chamber distance is much longer or much shorter than the standard length? There is a 4.5″ / 114 mm limit on how short the microCMA can be due to the geometry of the analyzer section. For longer flange-to-target distances, the analyzer section can be extended as needed. The photo below shows a short 5″ microCMA and a long 21″ / 533.4 mm microCMA.

microCMA Auger Electron Spectrometer

No matter what your flange-to-target distance is, if you have a 2.75″ / 70 mm flange available, it is possible to add the surface-sensitive analytical AES technique to your chamber. The microCMA and Auger Electron Spectroscopy are especially useful for MBE chambers and other research experiments that deposit thin films and where surface-sensitive elemental analysis is required.

For more information on the microCMA visit RBD Instruments’ website here – microCMA

Auger Spectroscopy

Auger Spectroscopy (AES) is a nondestructive and semi-quantitative surface analysis technique that works well for elemental analysis of surfaces on UHV compatible conductive and semi-conductive materials.  It is well suited for the analysis of thin films and coatings.

This ultra-high vacuum technique has high surface sensitivity (<100 Å) and a low detection limit.  It can detect all elements except hydrogen and helium.

Following are links to a variety of Auger Electron Spectroscopy tutorials which explain in detail the principles of AES, the instrumentation, and the applications:

Wellesley College AES  (pdf)

Hong Kong City EDU AES (pdf)

University of Delaware AES (pdf)

Johns Hopkins University Principles of AES

Auger_Electron Spectroscopy ( Power point download)

RBD Instruments’ microCMA is an affordable compact Auger Electron Spectroscopy (AES) cylindrical mirror analyzer package which is small enough to add to existing vacuum chambers.  For applications which require elemental information on the top most mono layers of specimens, AES can be the perfect solution. More information…


Click on the above image for a short video demo about the microCMA