Wavelength Tech Forum: X-Ray Spectroscopy

This month’s Technology Forum looks at the topic of X-ray spectroscopy and the trends and issues surrounding it. Joining us for this discussion are John E. Martin, with Spex SamplePrep, Bob Clifford, with Shimadzu, Drew Hession-Kunz, with Innov-X, and Mike Tice, with Strategic Directions, Intl.

How has portability changed the X-ray spectroscopy industry?

(Martin) The use of portable XRF systems has expanded the use of XRF in the market. The handheld systems have allowed metal sorting and quick screening of many applications. It must be realized that they are screening tools and not quantitative in many situations.

(Clifford) Although handheld fluorescence X-ray spectrometers affected expansion of the X-ray spectrometer market due to their ease of operation and low price, the sensitivity and precision are not satisfactory in many cases. In particular, the handheld or portable spectrometers tend not to satisfy users conducting microanalysis of metal samples.

(Hession-Kunz) Miniaturization of the key components of XRF, along with significant improvements in battery technology, have enabled near lab-quality analyses using relatively low-cost portable X-ray fluorescence analyzers. Our portables continue to press forward with ever-lower limits of detection and ever greater capabilities such as thickness measurement and lighter element analysis. Some of these technologies are migrating from our larger on-site instruments such as our ship-board oil and fuel analyzer or large automotive and recycling scrap systems.

Wherever these capabilities come from, users see the advantage of portables in the same light as a cell phone- they prefer to get answers where they are, rather than deal with the delay and cost of taking samples back to a lab or outsourcing to a contract lab. The new generation of analyzers now affords the breadth and LOD’s that the marketplace was looking for in on-site analysis, and they are willing to invest in.

(Tice) It's not just portability, but also the ease-of-use that has helped to really transform the business by taking XRF out of the laboratory and even out of the hands of trained spectroscopists. Relatively unskilled workers are now performing routine analyses on the factory floor and in scrapyards. This has really opened up the application space.

What do you see in the future for XRF?

(Martin) The design of more flexible XRF system whether EDXRF or WDXRF has pushed the use of XRF and increased the number of users. I see no reason that this expansion will slow down.

(Clifford) Fostering of chemical analysis engineers consumes significant time and costs. Thus, the XRF market will likely expand in the future – especially in the areas of semiconductors and the electronic material industry, which requires analysis of multi-layers with thin films and adherence to environmental regulation such as RoHS/ELV.

(Hession-Kunz) Developments in software and smaller, faster, and higher-capacity electronic components will continue to power future developments in X-ray spectroscopy. Look at Apple’s revolutionary new iPhone as an example. Some see its many features and benefits, and can turn them into fast payback by applying its technology to their needs. Similarly, the new X-ray fluorescence products will be driven by their capabilities and what they will offer the users. Users always lead manufacturers to new applications for a product this revolutionary, and our applications group is constantly amazed by the diversity of complex application questions our customers bring them. I am sure there will be many uses we haven’t even thought of that will become key markets over the next 5 years.

(Tice) Laboratory XRF will continue to provide incremental improvements in sources, detectors and software. In industries where the use of portable XRF has exploded, laboratory XRF may follow in order to provide more reliable and confirmatory measurements. Now that XRF is being more widely accepted by industry, it's possible that process instrumentation using XRF may become more common than just in the semiconductor industry.

Can XRD achieve the popularity of XRF?

(Martin) It is unlikely because XRD systems are more difficult to use and more geared for academic exercise. They require more attention by the operators and usually have a higher-level operator. Certain isolated procedures can be used in production settings but they are unlikely to expand like the XRF systems have.

(Clifford) Although the XRD market is expected to grow, in comparison to the demand for XRF, the growth will be relatively small. This is because the usage of XRD is mainly in the area of research and development, and the number of applications in the areas of production control and quality control is less than with XRF.

(Hession-Kunz) XRD is a "popular" analytical technology for many applications. However, the portability and ease of use of XRF makes it a more accessible tool for applied, industrial applications than XRD. There are semi-portable XRD systems in the marketplace that are used in the field, especially for geological studies. The two technologies complement one another quite well – one for elemental analysis and the other for speciation of the element.

(Tice) Probably not. Although XRD provides information on molecular structure that is difficult to achieve in other ways, the number of applications that require that level of detail is limited. XRD can be used to identify compounds, but it competes with other nondestructive spectroscopic methods such as the various forms of infrared spectroscopy. These other techniques are already better established. For these applications, XRD would not appear to offer any particular advantage.

How have the new RoHS/WEEE directives impacted X-ray spectroscopy?

(Martin) The RoHS/WEEE directives have presented the XRF community with many opportunities and challenges. The directive is not specific on sample protocols and how the items under the directive can be tested by an auditing agency. The handheld systems advertise that they have the ability to fulfill the RoHS directives but they can only be effective in a screening method. Testing agencies at first will ignore this limitation and then more quantitative methods will have to be developed. The real problem is the vagueness of the directive when it comes to selecting a sample for testing. A secondary problem for XRF is calibration standards.

(Clifford) Since WEEE is a recycling directive, it does not have much influence on the analytical instrument industry. On the other hand, the RoHS/ELV directives have had a great impact on X-ray spectroscopy, fostering improvements in instrument sensitivity and precision, and lowering production costs.

(Hession-Kunz) Not only has the European Union version of RoHS/WEEE but the Chinese implementation caused tremendous change in the manufacturing of electronics but also in how companies manage their supply chains and inventories. We all have seen the surge in sales of XRF analyzers from electronics manufacturers and their suppliers. However, this has led to further uses such as their potential to identify counterfeit electronic components, which continues to plague the industry. Thus, entire new uses for component inspection with XRF are becoming very important. And there are others in the RoHS-exempt categories (such as aerospace, military and medial manufacturers) seeking solutions to identifying the ever-tightening supplies of Pb-compatible parts in the growing world of RoHS supplies.

(Tice) Over the past two years, hazardous substance regulations have been the driving force behind the XRF market. Both portable and benchtop units have become the standard industry solution to compliance. These trends should continue for at least the near-term.

What are some application areas for X-ray spectroscopy that could be explored further?

(Martin) One area will be the further expansion into the RoHS area as various suppliers try to satisfy the requirements. Because XRF systems are smaller and cheaper and because EDXRF can compete with WDXRF for accuracy and precision many application areas will be possible that were closed to the big WD system. With the smaller system, point of production samples can be measured and you can get real feedback on process control at a much lower cost then the very expensive automated system that know exist. An example would be analysis of hot metal in the steel mills at the Blast Furnace and not at the main lab.

(Clifford) As mentioned, thin-film and environmental analysis in the electronic material industry could be explored. Additionally, further microprobe analysis, microanalysis, surface analysis and high-sensitivity analysis will be required.

(Hession-Kunz) The older conventional thinking about instrumentation has changed dramatically. The current marketplace with a high mix of Gen-Nexter’s (AKA--Millennials, Generation Y, and Generation Next) is a fresh segment of users that grew up with technology, are extremely comfortable with it, and seek solutions using new approaches. The marketplace will demand more and more solutions using X-ray spectroscopy that take advantage of the continuing developments in computers and offer improved user interface. Also, the present workforce of highly skilled technical staff is retiring in record numbers without obvious replacements. Thus, this type of technology will seem more mainstream than it has in the past.

(Tice) One area that comes to mind is in forensics or 'first responder' applications, such as identifying unknown substances or suspected explosives or illegal drugs. Recently, Raman and infrared spectroscopy have been applied successfully to this area, and it seems that X-ray might be successful as well. Allied applications, such as homeland security or airport security, also exist. Although X-ray imaging forms the heart of scanning CT technology for baggage, X-ray spectroscopy is really just beginning to be used to supplement these systems, and there is still room for improvement. Handheld instruments in the hands of security personnel might also provide some benefits.

What do you think?

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