NetNotes
using either the zero loss peak or a peak that is in both phases and does not have a chemical shiſt . You must also take care of eliminating X-ray peaks in your EELS data; otherwise they are identifi ed as unique phases. If you do this, you minimize the number of factors (components) identifi ed. Masashi Watanabe and Paul Kotula gave excellent tutorial talks at M&M’13 on the topic. Both are available online for viewing. You might have to contact John Mansfi eld for the link because I don’t have it available as I write this. T e advantage of the MSA approach is that your analysis gives you an image and so any inhomogeneities across your interface in terms of the concen- tration profi le would easily be identifi ed. It is also a totally unbiased analysis approach. Masashi is the author of the MSA plugin for DM and it is available through HREM Research. Paul is a co-author of the AXSIA soſt ware and a co-patent holder for it as well. I would highly recommend that you look up their publications on the topic, as they are very good reference articles to have. We just started using the AXSIA technique aſt er having Paul Kotula give us a tutorial at the Army Research Laboratory and are fi nding it a very powerful. It’s a bit more trickier with EELS that with XEDS, though. Scott Walck
s.walck@comcast.net Tue Mar 10
Digital Micrograph has a host of tools for dealing with 3-D data sets. There is a menu labeled “Volume”. This will allow you to rotate or project the data along any direction needed. For your application, you would want to project the data along the “y”. You will now have a 2D dataset with the projected intensity along the interface in the X-Dimension and Energy in the Y-Dimension. To save this as a series of files, you would then use the “File: Save As Series...” menu item. You can choose EMSA format for the file type and the EELS header information and calibrations will be preserved. You can also use the “Text” format, and then you only get the intensities. You can write a simple script in Digital Micrograph to do this. Below is an example. It took about 4× longer to document that actually write. For more information about scripting, there is a good reference section in the Digital Micrograph help file. You can also get a lot of information at the DM Script site at TUGraz
http://portal.tugraz.at/portal/page/portal/felmi/DM-Script . Also, a simple script to project a spectrum image into a line scan is available from Ray Tweston. Ray D. Twesten
ray.twesten@
sbcglobal.net Tue Mar 10
Image Processing: Bruker Esprit 1.9 offl ine software We just installed Bruker Esprit 1.9 offl ine soſt ware. Some problems
happened. T e fi rst one is when I was trying to do QMap for some existing ChemiSTEM HyperMap data, all the QMap images are just black but not with diff erent colors as usual. T e second one is when I wanted to make a new QMap method, an error happened like “cliff -lorimer: wrong primary energy in standard library”. So, I guess there may be some parameters need to be changed? I change the “Voltage range” to 200 KV in the “Microscope information” already. Qiang Wang 13qw9@
queensu.ca Sun Mar 29
Generally when you receive the message that you have a “wrong primary energy in standard library” it means that your spectra or map was recorded at a diff erent energy than that used to build the Esprit library. Go to the menu “Database”, then top right open the button “Standard Library” and select “new”. Accept to change the current library and fi ll the data for the new one: -any name you like, - elevation is the take-off angle, probably 18° or 22° for Titan or Osiris respec- tively, - azimuth the angle between the goniometer axis and the diode positions 45° - sample tilt that you used to record the data. Philippe Buff at philippe.buff at@epfl .ch Mon Mar 30
70 Instrumentation: high-resolution sputter coater
We have 3 FEI FEG SEMs in our building: a new FEI FIB, a 4-year-old FEI nanoSEM, and a 15-year-old FEI XL30 SFEG. We also have 2 older sputter coaters. A Polaron E5100 (1988) and a Denton Desk II. Both use mechanical pumps. Our Polaron is no longer working. T e problem of course is the visible grain at high mags (>50K×) with gold, gold/palladium, etc. It doesn’t matter if it’s the Polaron or the Denton. Same result: visible grain over 50K×. I need to justify with written rationale to our directors why we should consider buying a high-res coater. Simply stating “to complement our 3 FEG SEMs” is not enough of a reason to spend the money. T ey prefer I fi x the Polaron. Any ideas/ feedback from those who have already crossed this bridge would be helpful. Also, does anyone have a resource for parts for Polaron coaters circa 1988 models? Fred Hayes
fahayes@ucdavis.edu Tue Mar 31 At the risk of sounding too salsesman-y, I’d like to off er my thoughts on your situation. First, congrats on having 3 FEGs at your facility! T at’s always a good problem to have! A couple things to consider: As for the coaters, I would start with the following approach. First, fi gure out the size of the features you are looking for. You should have an idea of the grain size put down by each of your coaters. If the coating thickness or grain size exceeds the size of the features you are looking for, you will never see them. I would try stating it in such a way that you may be missing important information or obtaining inaccurate information from your samples because it is highly possible small features have been completely obscured by the thickness and or grain size of the metal coating you are currently using. I would recommend either an osmium coater or a high vacuum iridium or platinum coater, as you will be able to lay down much thinner coatings with grain sizes that may not even be visible. If you are working at very low accelerating voltages, know that almost all samples, regardless of how carefully they were prepared or stored, build up a thin layer of hydrocarbon material on the surface. When working below 2 kV, this contamination contributes signifi cantly to the image formed. Ideally it should be removed with a UV cleaning cycle (although a very low power plasma clean may work on some materials). Doing so may give a much better, and more accurate surface image, and may eliminate the need for a metal coating in some instances. In the end, I think a valid way to frame your request is by stating that you want to use the equipment and tools that will get you the most accurate data from your samples, and not leave your results open to questioning or second-guessing. If it results in saving time (samples come out right the fi rst time) or money (new systems come with warranties, less prone to breakdowns) that might also help. Jeff rey Hall
jhall@2spi.com Wed Apr 1
Instrumentation: carbon coater problem
Our lab had an EMS 450 carbon coater sitting on the counter top. I located the roughing pump in storage and am trying to make the system operational. All electrical operation seems to be working. I dumped out the old pump oil and replaced with new oil. Upon fi rst pumping down the system, the vacuum gauge leveled at 5 × 10− 1 mbar. I worked with the vacuum pump connections and was able to obtain 2 × 10 − 1 mbar. I ordered new seals for the jar that forms the vacuum chamber [the old seals are at least 10yrs old]. T e new seals just came in, and there was no improvement to the level of vacuum. One of the observations that I have made is that I obtain the best vacuum when I turn on the system in the morning. If I leave the system running, the vacuum level will steadily worsen, holding fi nally at 5 × 10− 1 mbar. Once I have cycled the system, I can never reach that level again unless I wait until the next
www.microscopy-today.com • 2015 July
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