Fred Ulmer, South East Regional Sales Manager, EDAX/Gatan
Roughly 10 years ago, I was introduced to the exciting world of research using Transmission Electron Microscope (TEM)/Scanning Electron Microscope (SEM) principles. Working first as a Gatan field service engineer, then service manager. It was my first crash course in these research principles. It was a lot to take in at the time, but the excitement and enthusiasm shown by a customer when they have their new piece of equipment installed and begin to generate data was such a payoff. It seems like every year that there is a new, exciting technique or technology to apply to user’s research that enables researchers to keep getting better data.
Recently AMETEK purchased Gatan, which allowed for a great partnership between already owned EDAX and newly acquired Gatan. Also, I switched to sales from service at this time, becoming the South East Sales Manager with Gatan, and shortly after, I became the EDAX South East Sales Manager. Again, a lot to take in at the time, but it was rest assuring that EDAX, like Gatan, is at the forefront of TEM/SEM research.
One of the most technological advances I witnessed was the introduction of the K2 & K3 direct detection cameras for TEM from Gatan. This technology has allowed users to achieve data that was previously unheard of. From cryo-techniques to direct detection Electron Energy Loss Spectroscopy (EELS), these systems have become a game-changer.
Figure 1. Breakthrough K3 result: 2.7 Å structure of the 20S Proteasome with the K3 camera and Elsa cryo-holder on a TF20. Data courtesy of Alexander Myasnikov, Michael Braunfeld, Yifan Cheng, and David Agard.
Unsure of how, or even if direct detection could be used in the SEM world, it was exciting to get word from EDAX that they were releasing a direct detection EBSD analysis system called the Clarity. This system is the world’s first EBSD detector based on direct detection technology. Current EBSD non-direct detection detectors have some drawbacks that include grain size and film thickness, causing localized blooming and some imaging artifacts in the EBSD patterns. So how does the Clarity overcome these drawbacks? It comes from the inherent design and technology of the detector. The Clarity does not require a phosphor screen or light transfer system. The technology uses a CMOS detector coupled to a silicon sensor. The incident electrons generate several electron-hole pairs within the silicon upon impact, and a bias voltage moves the charge toward the underlying CMOS detector, where it counts each event. This method is so sensitive that it can detect individual electrons. Coupled with zero read noise, the Clarity provides unprecedented performance for EBSD pattern collection. It can successfully detect and analyze patterns comprised of less than 10 electrons per pixel.
Figure 2. High-quality EBSD patterns collected with Clarity from a) silicon, b) olivine, and c) quartz.
Figure 3. Intensity profile across (113) band from the Hikari Super (blue) and Clarity (red) detectors showing improved contrast and sharpness with direct detection.
Direct detection will benefit many research areas like in‐situ microscopy, EBSD, 4D STEM, imaging beam sensitive materials, quantitative measurement of radiation damage, or quantitative electron microscopy. I am excited to see how the new generation of direct detection, like the EDAX Clarity, will continue to revolutionize the field of electron microscopy. Direct detection and electron counting are poised to advance electron microscopy into a new era. Let’s go direct detect!
I firmly believe that one of the factors that has helped EBSD advance as a microanalytical technique is that it makes beautiful pictures. Of course, these images are packed with valuable information regarding the microstructure of materials. But in addition to this scientific content, they catch your eye. In our lab, we have taken advantage of this by hanging the covers of different journals and publications that feature EBSD images collected with EDAX equipment (Figure 1). Some of these are images we have collected internally, and others are from our customers. It is a fun reminder of interesting work that has been done over the years.
Figure 1. Our EBSD cover collection.
We have had an exciting past 18 months with the EBSD product line at EDAX. We launched our Velocity high-speed CMOS camera, which delivers greater than 4,500 indexed points per second. We released the APEX Software for EBSD, our new data collection platform with powerful analytical capability coupled with an easy-to-use interface. We introduced our groundbreaking Clarity EBSD Analysis System, which is the first commercial direct detection system designed for EBSD. As part of the development, testing, and marketing of these new products, I have used these products to collect thousands of images, some of which are utilized to highlight the performance of these new tools.
So how do you choose what makes a good EBSD image? The first step is often picking an interesting sample, but interesting is in the eye of the beholder. Some examples are selected because they use specific materials, like aluminum, magnesium, or steel. I like samples that have interesting microstructures. Sometimes, this is from a novel processing approach, like friction stir welding or equal channel angular processing. Sometimes, it is from a multi-phase microstructure, where structure and chemistry can be characterized simultaneously with EDS-EBSD. Sometimes, it is application focused. In this example, I have selected a sample because it is an additively manufactured nickel alloy. Additive manufacturing is a market with growing interest, and the microstructure is important because it influences the final properties of the material.
Figure 2 shows an Inverse Pole Figure (IPF) map of this material, collected with the Velocity Super at >4,500 indexed points per second. This IPF map is colored relative to the surface normal direction, and I have included a (001) pole figure to show the crystallographic texture and a colored IPF key to help decipher the relationship between the colors and the crystal orientations, which is good practice. This image is interesting because it shows a (001) fiber texture, which explains why many of the grains are shaded red. This helps researchers understand how these grains were growing during the additive manufacturing process. But is it visually appealing? That’s a question I often ask as I share these images for different possible uses.
Figure 2. IPF Map of an additively manufactured nickel alloy collected with the Velocity Super at >4,500 indexed points per second.
One possible approach to improving the visual appeal of this map is to superimpose it with a grayscale image derived from other EBSD measurement metrics. Figure 3 shows the same IPF map combined with an Image Quality (IQ) map and a PRIAS (center) map. The IQ value is derived from measuring the brightness and sharpness of the diffraction bands within the EBSD patterns. The PRIAS map is calculated from the intensity of the signal onto an ROI positioned within the center of the EBSD detector. Both signals show microstructural contrast and add supplemental information to the IPF map.
Figure 3. IPF map combined with Image Quality (left) and PRIAS center (right) contrasts.
How about the colors, though? Is it too red? I hear that sometimes, but I wonder if it is because of the rivalry between the University of Utah (red – where I went to school) and Brigham Young University (blue – where some of my co-workers went to school). What can I do about this? One approach is to specify the IPF map relative to a different direction than the surface normal direction. Figure 4 shows an IPF map where I have selected a  sample vector. While it is harder to relate this to the fundamental additive manufacturing process, it does show how you are not limited to specific sample directions. This can be useful if, for example, the thermal gradient present during processing it not aligned with the sample normal direction. In this case, it gives us a different color distribution representing the same microstructure. Is this better?
Figure 4. IPF map relative to the  sample direction.
I have been looking at these maps for 25+ years now, so sometimes it is the new and novel that catches my eye. Figure 5 shows the same microstructure colored using a Quaternion Misorientation scheme. Here a reference orientation is used as a baseline, and the misorientation from this reference is used for coloring. Our OIM Analysis software has a wide range of different methods for visualizing microstructures. I personally really like the way this one looks. It is as much art as science.
Figure 5. IPF map with Quaternion Misorientation coloring.
When images meet those aesthetic criteria, they can be used for marketing, publications, covers, and even clothing. Figure 6 shows a scarf printed using an IPF from a skutterudite material. The crystallization of this material looks a bit like exploding fireworks. I have heard plenty of times that we should be in the tie or T-shirt business with the array of stunning images we can produce. I am always amazed that beyond visual appearance, the information on orientation, grain size and shape, deformation, and phase, among other things, that can be easily represented with EBSD. I hope to continue to find interesting examples to share with you. Special thanks to Tara Nylese for sharing the photo.
The seasons are changing here in the mountains of Utah. Autumn is at least one of my four favorites! I have made my home here, largely because of the drastic seasonal changes in climate and the ability to participate in gravity fed activities, like skiing and mountain biking. My personal life has become a game of maximizing my time in the mountains within the confines of what the weather and other commitments allow. Do I ride my bike at 5,000 feet elevation or 9,000 feet elevation? Do I pull out the skis or the fat tire bike for riding on the snow? Do I have to ride early in the morning when the ground is frozen to avoid the mud? Maybe I just escape to the desert for a weekend. No matter what the weather decides to throw at me, I have an answer. If I ever get bored, then mother nature will change things up for me soon enough. I have learned to adapt and enjoy the constant change.
Figure 1. A perfect autumn day on the trail.
Figure 2. Escaping to the desert. Maybe I will see Dr. Stuart Wright there.
Figure 3. Not enough powder for skiing? No problem.
Recently in my professional life, I have had to apply some of the same attitudes toward change. After spending my entire career with TSL, then EDAX, then AMETEK; I decided to leave and work for Gatan about five years ago. I was just shy of my 20-year anniversary with EDAX. It was a nice change of pace and scenery. I really enjoyed learning new products and getting in touch with cutting edge Transmission Electron Microscope (TEM) research applications that Gatan is involved with. Then the climate changed and AMETEK acquired Gatan! Things had come full circle, just like the seasons. Fortunately for me, selling EDS and EBSD is like riding a bike (pun intended)! I now get to associate with some old friends again and sell both Gatan and EDAX products. I’m trying to convince myself that there are never too many products to sell, just like you can never have too much snow. However, sometimes I wish there was more time in the day.
Figure 4. It’s impossible to have too much snow!
I am looking forward to the constant change that will come with the combined power of EDAX and Gatan products. Can we offer Gatan sample preparation equipment to EDAX Scanning Electron Microscope (SEM) users? We sure can! Check out the latest EDAX Insight newsletter to see an example. Can we offer heating stages to EDAX SEM users? Absolutely! Can we leverage the power of Electron Energy Loss Spectroscopy (EELS) and Energy Dispersive Spectroscopy (EDS) together with diffraction for the ultimate microanalysis experience for TEM users? I hope so! It will take some work, but like climbing mountains, it will be so worth it!
Figure 5. You can’t enjoy the descent without the hard work of climbing.
I am looking forward to being able to offer my customers more solutions to their research problems. No matter which way the wind blows; I expect to have the answer in the form of the combined EDAX and Gatan product portfolio. What research problems are you trying to solve? Let’s see what we can do together. See you out there!