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

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.

 

 

 

 

 

It’s relatively common for us to receive very small volumes of material for analysis. Often this is the total amount available so getting the right answers is extremely important. When these come in as powders, the answer is always to run them on a zero background plate, but sometimes that’s not the case. Luckily, there are other options for analysis of very small quantities.

The most common application for filter-membrane sample holders has always been respirable silica quantification. This is mandated by OSHA and is an extremely common industrial hygiene test. Ambient air is sampled with a fixed or mobile suction system and particles are deposited onto a PVC membrane inside a sealed cartridge. Testing procedures are defined by NIOSH7500 and since this is a total quantification method (not a relative method), it’s critical that the entire sample is measured. Unfortunately, the measurement cannot be completed on the PVC membrane as received. Transferring the sample powder to an Ag membrane is accomplished by dissolving or ashing the PVC away, diluting the remainder in a solvent and depositing it onto the Ag membrane by vacuum filtration. The end result is an extremely low loss of analyte even for very small volumes of material.

This preparation method is also very useful for other types of samples which might have crystalline particulate suspended in a solution. Drying samples can be time-consuming, heating them to boil off liquid can cause phase transitions in the crystalline analyte, and handling dry powder in very small quantities is a very good way to lose material. Vacuum filtration solves all these problems.

 

Our most popular custom sample holder is the SC40F25 which is designed to hold the common 25mm Ag membrane filters used for this type of mounting. The anodized Al body is a time-tested design that works very well and causes almost no interference with the data, unlike the original injection-molded plastic parts. However, the most common method for retaining the membrane has always been to drop a metal support disk behind it and use an ID snap ring to retain both the disk and membrane. This can be a frustrating operation even for experienced hands. Snap rings are hard to control and the high spring tension gouges the inner diameter of the Aluminum body to the point that the holders must be replaced periodically.

After watching so many clients struggling with this system, we thought we could find a better option. The first step was a simple, laser cut acrylic backer instead of the metal disk. The acrylic was thicker which limited the depth to which the snap ring needed to be set. This was an improvement but still required the snap ring.

The next step was 3D printed plugs which could be pushed into the well. These supported the membrane and held it in the plane of diffraction at the same time. A standard pair of pliers was all the was needed to grab the plug and gently rotated it to release the membrane. This seemed like the ideal solution, but we heard from one user who claimed that the plug was causing an interfering peak in his measurements. We’ve been around the block with 3D printed sample holders in general and it’s definitely true that the common thermoplastics used will crystallize when cooled rapidly. This causes lots of problems for routine analysis of powders, but this was the first we’d heard of a peak being visible through an Ag membrane. Perhaps this user had a particularly thin membrane, but regardless, we needed a new solution, both for their lab and our own.

 

Our current solution is a laser cut “spring” backer which again combines the function of retainer and support in one part. The spring is easy to install by hand and can even be removed by hand, but forceps or needle-nose pliers make this easier. These have been working very well so we’re hopeful that this is going to be a long-term solution that we can share with our clients.

 

 

 

Posted by: In: Uncategorized 03 Jan 2018 0 comments Tags: , , , ,

Most of the zero-background sample holders we make are designed with permanently affixed plates. We prefer this dramatically as loose plate are constantly getting dropped, chipped, or lost. However, a permanently affixed plate also gives us the freedom to precisely (within about 0.02mm) set the depth of the plate below the plane of diffraction. This can make a big difference in the results depending upon the volume of powder loaded as the standard “flush mount” puts the plate exactly in the plane of diffraction. This works fine for very small volumes, but it does guaranty the there will be a displacement error of some magnitude regardless of the particle size or volume. For this reason, we always offer custom recessing as an option. The only drawback to the permanently affixed style of mounting is that the offset (or flush mounting height) cannot be changed. Our preferred solution is to simply create a set of holders with various depths to accommodate different sample thicknesses, but we had a request recently for an infinitely variable mounting solution.

Complicating the project is that the holder was to be used in a D2 Phaser with a 6 position autosampler which does not use the same style of base holder as the single-sample variant or any other Bruker XRD that we’re aware of. We discussed several options. The large number of heights needed made multiple holders, spacers, and any other solution that relied on discreet steps unacceptable. The thin-walled sample bases and relatively tight dimensions made a screw-in insert unrealistic as well. The final solution was to build a custom tool for setting the ZBH at a specific depth. This requires the user to work with bare Si plates, but it meets all the design criteria and we’re hopeful that this will work well for them.

The tool is made from acetal (Delrin) plastic which is extremely resistant to chemicals, adhesion, and abrasion. It’s actually an ideal material for threaded parts and machines very well.

Posted by: In: Uncategorized 03 Jan 2018 0 comments

I spent quite a bit of time during my college career in chemistry and electronics classes, but when I think back on the most influential aspect of my education, it was my physics classes that shaped my understanding of the world more than any of the others. There was something very “pure” about the process of isolating the variables necessary to describe a mechanical event or electromagnetic interaction. These numbers fit together like pieces of a puzzle until, all at once, the answer emerged. This concept of manipulating what was available to create what was needed seems to permeate much of our work at Texray and KS Analytical Systems and it’s the most satisfying part of it for me. We’re frequently approached with problems that require a custom solution.

Much of the custom work we do revolves around holding samples in various form while they’re being analyzed, but recently we’ve had a few projects more centered around improving processes which have been interesting. For our own lab, this might mean custom racks to keep tools organized and clean, sample tools to help us avoid cross-contamination or fixtures to aid in the safe handling of some of our more expensive apparatus. We just completed a project that I found interesting for a client in CA who is running seal-cell experiments which needed to be held secure to various working surfaces. The original method involved bolting them in place each time which proved time-consuming as volume increased. The answer was a relatively simple adapter plate designed by the client which needed a little design refinement and some basic fabrication.

The project started with basic drawings so the first step was a few prototypes in acrylic plastic courtesy of the laser cutter. Small changes were made until it was ready for an Aluminum version. Here it is in action!

Posted by: In: Uncategorized 21 Jun 2017 0 comments Tags: , ,

KS Analytical Systems and Texray Laboratory Services are deeply invested in the future of science and technology in the USA. We work with undergraduate, graduate and post-doc students regularly and encourage them as much as possible with support through Texray as well as technical information. Watching XRD and XRF users in higher education develop and test their ideas is always interesting, but these are not the students who are being lost from STEM fields. The battleground for the engineers, chemists, and physicists of tomorrow is happening at a much younger age so we’re always looking for opportunities to support teachers who are working to show their students that these fields are not just endless equations and tedious experiments.

With the whole country waking up to the need for more STEM graduates, there’s no shortage of organizations and competitions set up to give kids a chance to get their hands dirty with technology. We started out by sponsoring a local high school robotics team and, most recently, a high school team entered in the NASA Human Exploration Rover Challenge. The video below is from last year and I love how they describe their early failures and determination to improve. These are not your ordinary shop-class kids. Most had never used even basic hand tools. This competition put them completely outside their comfort zone.

The 2017 competition brought new challenges and more restrictive design constraint intended to push the teams further into the realm of custom components. The obvious answer for most of these vehicles had been common bicycle wheels and tires from the beginning. Their light weight and high strength make them very attractive, but taking the easy way out is not what being an engineer, let alone a NASA engineer, is all about. Using the equipment and capabilities at hand the Parish Episcopal team developed a wheel that took everyone by surprise (including myself). Multiple layers of cardboard were sandwiched together and coated in a polymer bed-liner material intended for pickup trucks. The toothed pattern of the cardboard layers created exceptional traction and the rubber coating made them extremely durable. The 2017 rover was not without its weaknesses, but these wheels were a subject of interest to everyone from the spectators to the organizers. Parish fielded two teams which finished 26th and 27th out of a 99 team field which included universities and high schools from all over the world.

The first video is from a TED talk given by two of the older students in the program from 2016. The second is from the 2017 competition and includes some race footage.

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!

A great many factors affect the quality of data one can collect on any given instrument, but there are times when simply holding the aliquot is a major hurdle. We spend a great deal of time working out the best ways to hold odd samples and even create custom hardware to do so in some cases. Click here for some of our other posts related to the various sample holders we work with. Choosing the best sample holder for a given project is one thing, but there are also times when a completely different stage is required.

The most common stage is the simple, single sample stage. This relies on three pins to define the plane of diffraction. The sample holder is pressed against these pins by a spring loaded plunger beneath it.

Posted by: In: Uncategorized 01 Apr 2017 0 comments

The days of inconsistent coffee are over. The world’s leader in elemental and crystallographic analysis instrumentation is bringing the same cutting edge technology used in their research-grade laboratory instruments to the food service sector. The “Brewker” B8 percolation instrument has revolutionized the hot beverage industry by applying the same stringent repeatability techniques employed in their XRD and WDXRF machines to the humble coffee maker.

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Key features:

  • Six lab-grade thermocouples monitor water temperature throughout the brewing process to ensure optimal consistency from the top of the grounds to the bottom.
  • The internal water purification module produces high-grade distilled water from any tap source. Subsequent particulate filtration, UV sterilization and ion-exchange operations are performed simultaneously because honestly, if you wouldn’t put it in your HPLC, you shouldn’t put it in your coffee.
  • Hall effect flow rate sensing controls the filling rate to within 0.001 L/m. A variable speed pump with high frequency bypass system adjusts fluid pressure 200 times every second.
  • Primary water is heated by the integrated inductive furnace and platinum boiler for the highest purity possible.
  • The effects of ambient temperature fluctuations are mitigated by the in-situ microwave temperature stabilization system which maintains water temperature to within 0.02 degrees C from the boiler to your cup.
  • The “Grounds Control” system integrates a proprietary laser particle size and CCD based shape analyzer for ultimate control.
  • A fully automated Nitric acid flush cycle guarantees that residual contamination does not exceed 100ppt from cup-to-cup.

 

Optional:

  • For the highest quality coffee possible, “Brewker” exclusive Poly Crystalline Diamond (PCD) coated Pt coffee mugs are recommended.
  • Basic and premium coverage support contracts are available on an annual basis. Remote diagnostics are possible when the B8 is connected to your site LAN.
  • All temperature and flow rate tolerances may be reduced by 50% when the “Brewker” B8 is equipped with the optional line voltage conditioner and UPS module.
  • The “Starbucks” discrimination function extends the Grounds Control capabilities to include protection against inferior, consumer-grade coffees.
  • GC/Mass Spec and ICP quality assurance system analyzes aromatics and final composition.
  • For the ideal grind, there’s no better option than the new McCone Micronizing coffee grinder. The combined shearing and impact action of 50 individual elements offers unparalleled particle size and shape consistency.
  • Free NSF grant proposal consultation for all degree-granting academic institutions! The only thing that makes this coffee taste better is knowing that the American taxpayer funded it!

IQ/OQ/PQ documentation is available along with full 21 CFR Part 11 data logging and audit trail generation. Don’t let your break room be the weak link in your GMP protocol.

Contact our sales department for a quote today. You can’t put a price on the world’s most precise cup of coffee, but you’d better believe we’re going to try.

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.