AN ANALYTICAL XRAY SERVICES LABORATORY
Feel free to call us: 940-784-3002

The D2 Phaser 6-position autosampler uses a completely different sample holder that their other systems. We’ve just completed our first production run of these blanks so they’ll be ready for custom orders. Contact KSA for more information.

XRD patterns are complicated by a variety of undesirable effects. Some of which are easy to deal with, others are unavoidable. One of the issues we see often is scattering and diffraction effects that are actually being caused by the sample holder itself. These effects can usually be modeled out, but simply knowing which artifacts are being generated from scatter off the sample holder vs amorphous content or phases present in the sample itself can make the difference between an easy analysis and a grinding, iterative march toward a final result. One of the most common effect we see is scatter from plastic sample holders. Most of the sample holders we produce are either Aluminum or PMMA plastic, but either way, one of the easiest ways to avoid undesirable scatter is to simply enlarge the sample well. We’ve been doing this for decades on the standard, non-rotating sample holders by cutting a large, rectangular well rather than the standard, 25mm circular well.

This week we did a little experiment to see just how much larger our sample well needed to be to eliminate the common PMMA hump at ~13 degrees 2Theta (Cu energy). It turns out that an increase of only 5mm in diameter made a huge difference in the total scatter even with very “wide-open” optics. See the scan images below for a real-world picture of the difference we saw. This may not seem like a significant problem until you’re looking for phases with D-spacings down in that region near the hump. Analysis of clay minerals can become particularly complicated. This is a great example of why we love talking to clients and XRD users around the world.

MDI Jade has been our goto analysis suite for powder XRD data for decades now. Powerful, versatile, and well supported, it’s earned a following second to none in the industry. What began as a simple suite of MS-DOS-based programs in the early 1990s has blossomed into a full-featured toolset for just about any kind of powder XRD analysis one could need. As computer hardware and software platforms evolved, Jade grew right alongside them with more powerful features, faster processing, and even greater flexibility.

Several years ago it became apparent that the core programming of Jade was going to become a limiting factor in its development. Enter Jade 2010.  Built from scratch on next-generation architecture, Jade 2010 freed up the developers at MDI to implement many of the changes they’d been wanting to add for several years. The result was a beautiful new interface with streamlined and reorganized menus that greatly improved the user experience. The new structure allowed for much more integration between features that had once been modular, making them easier to use as well as more powerful. The original Jade suite (now on version 9.8) became Jade Classic and it became clear that there was a sunset coming for the venerable program. The only complaint we ever received about Jade 2010 was that it was only available as an annually-licensed product. Each year the users would need to renew their subscription to continue using the software. This gave me pause just as it did many of our clients, but the rapid pace of development almost necessitated this as new changes and updates were taking place monthly rather than yearly as they had in the past.

Fast forward a few years and we’ve had another big change. Jade Classic (9.8) has been discontinued and Jade 2010 has become Jade Pro. It’s still all-inclusive with all the advanced capabilities available on every license. It’s also still an annually licensed program. Development will continue free from the limitations of the old core programming and the distraction of maintaining two completely separate products.

This alone wouldn’t be such big news, but there is a new option that we’ve been waiting for years to see. Jade “Standard”.  We now have four additional products available to users with more limited needs and budgets.

Jade Standard level 1 includes all the basic pattern analysis and manipulation tools that users would need for many of the more common projects as well as some of the more advanced features that were only offered on the premium Jade+ (plus) program before.

Jade Standard level 2 includes all the level 1 functionality, plus Search/Match (2a) or Whole Pattern Fitting/Rietveld (2b).

Jade Standard level 3 includes both Search/Match and Whole Pattern Fitting.

All Jade Standard products are perpetually licensed (One-time purchase, lifetime license).

Several of the ancillary tools offered by MDI are still available as always including Ruby, ClaySim, and RIQAS.

We’ve been waiting a very long time to be able to make this announcement and I must say that the way this has been implemented couldn’t be better for ourselves or our clients.

Please contact KS Analytical Systems for more information and upgrade pricing.

We often receive requests for small powder wells to be ground into our zero-background sample holder plates. I usually try to talk the requestor out of this as it has limited usefulness for most applications, but there are some reasons one might benefit from this type of holder. It’s for these special cases that we’ve always offered custom ground wells in our ZBH plates and we continually improve our process to give our clients exactly what they want and need to get their work done.

There are three reasons I try to avoid this.

  1. It adds cost. The very small grinding tools required for this cut very slowly. This is partially to avoid building up heat in the plate which will shatter if it goes too far. In the foolishness of my youth I once tried to score large wafers with a CO2 laser. After two passes it would explode leaving about 50% waste material, but it got the job done. Heat is your enemy when it comes to very hard materials like this. We also don’t use pre-ground plates. Each one is machined from a flat plate after it’s been mounted in the sample holder to ensure perfect alignment with the plane of diffraction while also giving us the freedom to cut any shape/depth we could want. I.e. if one wanted a square or oval shaped pocket, we could machine that. All this flexibility adds up to additional work/time which adds to the cost of each holder.
  2. It’s often unnecessary. If you have enough material to fill most wells, it probably won’t be transparent to x-rays anyway. I find that many users of sample holders with wells could get by without them by simply using a smaller well in a standard sample holder. The additional scatter from PMMA plastic may or may not be a problem, but if the user can live with it, it’s a huge cost saver.
  3. As soon as we break the surface, we’re no longer dealing with a monocrystalline material. I’ve never seen any practical evidence that this causes a problem, but it’s always concerned me that grinding these plates essentially creates a polycrystalline material at the surface of the well. I would love to hear from anyone who’s ever seen a weak Si pattern superimposed on their data.

One alternative I often recommend is recessing the entire plate by some number of microns to accommodate different particle sizes if that’s a concern. I believe that many XRD users are asking for sample wells in their ZBH simply to avoid the displacement error inherent in mounting their powder on top of a plate which has already been fixed at the plane of diffraction. Recessing the plate allows us to retain the polished surface of the ZBH and allows us to mount it with at least the same degree of precision that a well would provide. Precision mounting adds about as the same cost as grinding, but it definitely has benefits. To my knowledge, KSA is the only company offering this type of mounting.

So that was an awful lot of reasons to avoid this, but there is one very big benefit of using a ZBH with a ground well. This allows you to run very small volumes of sample material while maintaining a very consistent irradiated area. Imagine the same volume of powder spread across a flat plate. Each time this is done, a slightly (if not significantly) different surface area of the plate is likely to be presented. The end result of this will be variations in intensity and perhaps preferred-orientation. Particle statistics change with varying numbers of crystallites in the plane of diffraction as well. This is all complicated by the changes in the irradiated area throughout a normal scan with divergent-beam optics.

The well pictured here is 12mm in diameter and 0.2mm in depth and a good example of the kind of custom work that is most common for us.

 

XRD sample prep is like a box of chocolates. You never know what you’re going to get… So many materials are fluffy or sticky that even after fine grinding, it’s common to have some clumps that just don’t want to break up. This became a problem for one of our clients using our side-loading tool so they added a piece of mesh to the mouth of the funnel. Their next order included a request for some type of removable solution for this so we mounted some coarse mesh in an acrylic frame that sits nicely on top of the funnel and makes it very easy to sift through sample material as it’s being loaded. We love these so they’ll be an option on all future orders!

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Clay minerology is a fascinating subset of the common powder XRD applications we work with. It seems like every lab has their own unique way of handling the various challenges presented by clays and hence the need for myriad solutions. Most recently we worked with a lab which processes large volumes of clay samples in their various Bruker XRD system and they needed a sample holder that would accommodate their 26 x 26mm glass slides on which their clays are mounted. The solution was a custom holder with a square recess for the plate which is simple enough, but in cases like this, one must take into account the real-world challenges of machining as well as usage. The edges and corners of the glass slides are the least precise part of the plate so the holder has a “moat” around the perimeter to eliminate binding or shifting due to those issues. The center is also relieved as this area does almost nothing to improve precision of the mount, but will cause dramatic displacement errors if any debris gets between the holder and plate in that area.

These were a little time-consuming to make, but the end result worked beautifully. The client was very happy and we’re happy to have another design to offer to other labs with similar needs.

 

I’ve spent time in hundreds of different businesses over the last 20 years as I traveled around the country working in labs and it’s given me a strong appreciation for the concept of “workplace culture”. It’s not really a spectrum in the sense that there are extremes on each end and compromise in the middle, but more like “culture” in the truest sense of the word. It’s a complicated system of expectations, relationships, and accomplishments. Obviously some of these systems “work” and others… Not so much.

I like to think we do pretty well at KSA and Texray. Mainly because, after many years of experimentation, I’ve come to the conclusion that I can’t change people (surprise!). An old friend at a major manufacturer of X-ray instrumentation once commented to me that when he hired a new tech, he’d know within a month if they were going to last. My first thought was that it would take longer than a month to make the new hire into the tech you needed, but I realize now that his statement embodied the same lesson it would take me years to learn. You can train, reward, chastise and incentivize all you want, but the people you hire are either right for your group or they’re not.

Around here we have easy days and hard days. It comes with the territory, but I think everyone knows that they’re appreciated and supported in what they do. Individual projects are encouraged and we try to loosen up enough to have fun without compromising performance. Behind it all is a sense of pride in the fact that we work very hard to surpass the expectations of our clients.

 

 

 

 

 

I spend a great deal of time meeting with XRD and XRF users throughout the year, but usually in the context of some problem or time-sensitive project. Luckily I’ve been able to attend the Denver X-ray Conference fairly consistently over the last few years. It’s a great time to catch up with other users who are as deeply invested in X-ray spectroscopy and crystallographic analysis as we are. The vendors always put on a great show in the exhibit hall and poster sessions.

The first three days of the week are filled with technical workshops focused on an array of topics. There are always some introductory classes for both XRD and XRF for new users to attend and then there will be additional topics which are usually more advanced. The educational opportunities alone are well worth the attendance fee. Each session is run by an expert in the field and questions, even from industrial users, are welcomed. The sessions are strictly non-sales oriented as well which lends the event a very egalitarian feeling. See the full program here.

Plenary sessions and more sales-oriented meetings occur later in the week and are a great way to get a feel for the cutting edge technology being released by the various vendors. The exhibit hall opens a few days into the conference so everyone has a few days to see all the different booths. We always spend a great deal of time at the Materials Data, Inc and Bruker-AXS booths in particular.

The conference moves between Westminster, CO just North of Denver, Chicago, IL and Big Sky, MT. I’ve never made the trek up to Big Sky, but I hear it’s beautiful. Some attendees only come when it’s up there.

I’d love to connect with as many of our readers as possible so contact us if you’ll be there and I’ll be sure to see you while I’m at DXC-Big Sky!

The dreaded “amorphous” hump created by x-rays scattering off plastic sample holders has plagued XRD users for decades. It’s a serious enough problem that we make a good volume of these holders from Aluminum which works very well for loose powders. The plastic scatters xrays at around 13 degrees 2Theta (Cu anode tube) which make a real mess of most geological patterns and isn’t fun to model out for Rietveld refinement. Zero background holders like our ZBH-32 work wonderfully in standard sample stages designed for a single sample at a time, but the large plate isn’t compatible with the autosampler.

 

I recently had a request for a hybrid holder which would allow for analysis of very small volumes of materials while retaining compatibility with the autosampler. This is almost identical to our standard powder holders, but with a well designed specifically for our small ZBH plate.

Key features include:

  • 6061-T6 Al material (anodized or as-machined)
  • Si(510) plate
  • Raised sample well minimizes the area of the sample holder in the plane of diffraction. (Original Siemens design)
  • Beveled well walls minimize the area of Al in the plane of diffraction
  • Other small modifications are made to improve reliability of these holders in the autosampler

One of the fundamental facts of lab-based X-ray production is that our x-ray tubes emit much more than the pure KA1 lines we rely on for material characterization and quantification. Most XRD users are familiar with techniques and hardware for the reduction or elimination of KB1, W LA1 and Bremsstrahlung, but take for granted the inseparable pair of KA1 and KA2 (referred to as the “doublet”). Luckily for us, these energies are present in strict proportion such that we can factor their paired presence into most XRD analysis to the point that one might barely notice their effect. However, the fact remains that we will see peak broadening at lower angles and completely independent additional peaks at higher angles due to this superfluous discrete emission.

Separating the doublet cannot be accomplished electronically or through absorption/attenuation such as might be effective for KB1 energies. It must be done in the primary-beam with an additional diffraction event. Primary-beam monochromators are generally classified by the number of diffraction events required for a photon to pass completely through the device. Single-bounce, 2-bounce and 4-bounce geometries are common with the latter providing the best energy resolution allbeit the lowest intensity (photon flux). My limited experience suggests that while the single-bounce models retain enough intensity to have some application in powder XRD, the others are relegated to HR-XRD applications such as XRR.

The alignment for any of this hardware is not for the faint of heart as it begins with coarse adjustments using fluorescent screens in the beam path. This was essential for us given how dramatically misaligned the monochromator had become after so many attempts to bring it back into operation. We actually needed our SDD system to verify that we were tuning for Cu KA1 energy rather than the KB1 emissions because some of the most basic aspects of the alignment had pushed way beyond their intended position.

Along the way we built ourselves a motorized remote adjustment tool which we’ll return to the user as small adjustments are required on a regular basis with this kind of monochromator to retain maximum intensity. It’s quite useful and even versatile enough to allow for the adjustment of multiple control knobs.

One final note regarding intensity. It’s easy to get excited about energy resolution like this, but bear in mind that we’re looking at ~20x reduction in intensity due to the inherent losses involved in the primary diffraction event. This data was collected at 10x the normal speed and at half the normal 2Theta step increment so it looks very good, but one would need a compelling reason to slow their data collection this much.

Another side effect of performing your energy discrimination in the primary beampath is that other issues such as fluorescence effects (incident x-rays exciting elements in the sample causing high background intensities) are harder to avoid than they would be with a diffracted-beam monochromator. The 4x reduction in intensity inherent in the diffracted-beam monochromatization makes it a poor choice to eliminate these effects when the incident intensities are already so low. We recommend energy-dispersive detectors such as our SDD-150 to eliminate extraneous energies without sacrificing net intensity. We’ve also worked with the Bruker LynxEye XE-T detector which has a very high energy resolution compared to other position sensitive detectors (PSD). Contact KS Analytical Systems for more information on these options.