microCMA Length, the Long and Short of It

Print Friendly, PDF & Email

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

Monochromator upgrade for PHI 5600 XPS system

Print Friendly, PDF & Email

Installing a monochromator

This blog post shows the steps required to install a monochromator upgrade on a PHI 5600 XPS system.

The components of a monochromator upgrade include the monochromator housing, the crystal substrate and aligner, the mono X-ray source, and the X-ray source aligner.    If your X-ray source is a 32-095 then you will need to replace that with a 32-096 that can drive two x-ray sources (standard dual anode and mono source). An additional water line is included to complete the cooling circuit between the standard and mono X-ray sources.

monochromator schematic

Step by step procedure:

First, vent the vacuum chamber.

Use a new 4 5/8” copper gasket and install X-ray source X Y Z aligner to the monochromator housing.  It is much easier to install the X Y Z aligner onto the mono housing before the mono housing is mounted to the chamber.

X Y Z aligner

Use a new 6” copper gasket and Install the monochromator housing to the chamber on the flange that is opposite of the hemispherical analyzer.  It is heavy and so you will need at least two people to mount the monochromator housing to the flange on the chamber. 

Once mounted tighten the nuts on the flange.  In my experience, going in a circular pattern is the best way to tighten flanges on UHV chambers.   The trick is to not over-tighten the nuts or bolts as you go around.  Start out with just a little bit of torque and gradually increase it as you go around.   One or two of the nuts on the back of the monochromator housing are exceedingly difficult to get to.  A ½” U-shaped or half-moon wrench makes getting to those nuts easier. 

Or you can simply cut a standard ½” wrench in half. 

Once the nuts are tight and there is no gap between the flanges it is sealed.

Install the mono crystal substrate into the top mono flange assembly:  Use gloves and very carefully remove the crystal substrate from its box and unwrap it, being careful not to touch the crystals.  There are 3 recesses in the crystal block that line up with flat spaces on the mono flange assembly. 

The crystal substrate is held in place with 3 clamps.  The clamps mount on a guide screw and then there are two spring loaded set screws that provide tension to hold the crystal substrate in place.  

Tighten the set screws to where they just start to tighten up, and then about 1/16” more.   Do not over-tighten the set screws.  They should be tight enough to hold the crystal substrate in place firmly, but not so tight that the springs inside the set screws are fully compressed.

Next, install a new rectangular Helicoflex type monochromator gasket into the top of the monochromator housing. It will sit into a recess and should be centered in the recess.

Put the mono housing shutter in the bakeout position.  The chamber will be baked out and so the shutter will need to be set prior to the bake out.  Also, you can see how the shutter works before the top mono flange is installed.

Install the top mono flange assembly onto the top of the mono housing.  This can be done by one person.  Make sure that the crystal substrate does not touch the sides of the mono housing as you lower the mono flange assembly.   There are two guide pins to hold the mono flange assembly in place.   The serial number on the mono flange assembly should line up with the serial number on the mono housing.

Install the bolts into the holes in the mono flange assembly and tighten them.   For this flange, use little torque as you tighten the flange in a circular (rectangular) pattern.  The bolts are coarse threads and you want to tighten the flange evenly. 

Once the bolts are tight and there is no gap between the two flanges then it should be sealed.

Use a new 6” copper gasket and mount the 10-610 mono X-ray source to the 6” flange on the X Y Z aligner and tighten the nuts until there is no gap between the flanges or until the nuts are very tight, which ever comes first. 

At this point the chamber can be pumped down and baked out.   Make sure that all the housing parts and O-ring seals are removed from the 10-610 mono source prior to bake out.

The pictures below show the components of the 10-610 X-ray source as they are reassembled after the bake out.

After the chamber has been baked out, refer to the 10-610 mono X-ray source and 10-420 monochromator manuals for outgas, operation, and alignment information.

High-speed Support Improved in Latest Actuel Release (1.7) for the 9103 Picoammeter

Print Friendly, PDF & Email

RBD has released Actuel version 1.7 for the 9103 Picoammeter, with improvements for high-speed data acquisition and (especially) data logging and graphing.

The latest version can be found here.

If you do not have a high-speed 9103 Picoammeter and are already running Actuel version 1.6, there no reason to download the latest version. However, high-speed users will find a number of improvements.

Oscilloscope emulation

Although Actuel was not designed to have an oscilloscope emulation (with features such as triggering), at higher speeds you can come close to emulating scope current monitoring.

In the Data Window, click the Show Options button and select “Last” from the Graph Options. You can scroll in increments as low as 0.1 second, but you can type in a smaller increment, such as “0.05” in order to display at higher resolution.

Last time option in Actuel
Using the “Last” time option in Actuel

(Note: The graph display options can get out of sync with data collection if you change and option when recording or after stopping and clearing data – it may be necessary to re-enter the value or reset recording. We’re working to make this smoother in the next version.)

For smoother real-time graphing, use standard-speed at 25 mS unless faster rates are needed

The 9103 can run as fast as 25 mS per sample in standard-speed mode, and 2 mS per sample in high-speed. In order to optimize faster data acquisition in high-speed mode, the 9103 collects 10 samples per message, as opposed to 1.

However, note that if you are collecting data at 25 mS in Standard-speed, your PC will be updated with new data every 25 mS. In High-speed, you’ll be updated every 250 mS.

For that reason, the Acutel software always collects data in standard-speed mode at 25 mS and above, regardless of the high-speed mode settings. It is recommended you do the same if you are writing your own software to control the 9103.

That also means that for real-time graphing, you may not want to sample at a rate of, for example, 24 mS, if you can achieve the same results at 25 mS. At faster rates, the delay in caused by receiving 10 samples per message is less noticeable, but it’s visible at rates of 20 mS- 25 mS if you are graphing only the latest points in relatively high resolution:

Actuel 25 mS Standard Speed

Actuel – 25 mS Standard Speed

Actuel 25 mS High Speed

Actuel – 24 mS High Speed