of course, I don't think this and I realise the title is controversial, but hopefully attracts some thoughts. It is worth thinking about for the following reasons:
innovation - with one global manufacturer it is increasingly hard to demonstrate 'value' to purchasing departments and it technique-wise it hasn't *really* advanced much in the last few decades.
cost - It's increasingly expensive to run (I have an £80k pa service contract which is completely unjustifiable), whilst new equipment is simply replicating the old with few added advantages (see above)
alternatives - Other techniques are increasingly cost effective and offer 'more' to the uneducated user e.g. LA-ICPMS, multiple large EDS detectors on SEM's, SXE detectors etc.
I obviously would like to move to a new instrument - but, if I were honest, I am struggling to see what the utility and business case is for users in the next decade. At best I can see the return of national centres given the financial pressures on research funding worldwide, especially in the earth and planetary sciences. I'd obviously like to be wrong.....
You bring up some good points.
Quote from: jon_wade on November 28, 2025, 09:51:38 AMinnovation - with one global manufacturer it is increasingly hard to demonstrate 'value' to purchasing departments and it technique-wise it hasn't *really* advanced much in the last few decades.
Well, I agree that hardware-wise the microprobe hasn't developed hardly at all. We keep hearing about solid state detectors on WDS but it never seems to happen.
But on the software side, I think we've seen a few improvements over the last few decades, if I say so myself. For example we can acquire and rigorously quantify x-ray maps where every pixel is treated as a point analysis for ALL quant corrections:
https://epmalab.uoregon.edu/pdfs/Donovan_2021_Amer_Min_2021-7739.pdf
Not to mention better background corrections, TDI corrections for beam sensitive samples, etc., etc., including logarithmic dead time corrections good to 400 kcps.
This last correction allows us to acquire quantitative x-ray maps at much higher beam currents than was possible in the past, thus reducing pixel dwell time and hence total acquisition time, while still maintaining quantitative accuracy:
https://pages.uoregon.edu/donovan/download/Donovan-etal-DeadTime-2023.pdf
Back on the hardware side of things, the problem is that there was not much competition to begin with and now there's even less as Cameca ends EPMA production and companies seek to silo their product lines where there is the least competition . E.g., Cameca moving to SIMS and Atom probe and Thermo vertically integrating their products.
Quote from: jon_wade on November 28, 2025, 09:51:38 AMcost - It's increasingly expensive to run (I have an £80k pa service contract which is completely unjustifiable), whilst new equipment is simply replicating the old with few added advantages (see above)
Instrument maintenance is a major cost of ownership. This is exactly why we hired a dedicated instrument engineer for our CAMCOR facility. Yes, he's not cheap, but we get instant response and he costs less than service contracts for a dozen instruments!
And any new major instrument (TEM/SIMS/etc.) you buy is multi-millions of dollars these days and the staffing and maintenance over its lifetimes is 5 to 10x of the original purchase price.
Quote from: jon_wade on November 28, 2025, 09:51:38 AMalternatives - Other techniques are increasingly cost effective and offer 'more' to the uneducated user e.g. LA-ICPMS, multiple large EDS detectors on SEM's, SXE detectors etc.
Each technique has it's advantages and disadvantages. If one requires the best attainable compositional accuracy, well, WDS/EDS EPMA is still the way to go... and yes, this could be a long discussion, but I will just point out that one can buy a JEOL microprobe with two EDS detectors or a SXES and an EDS with 5 WDS spectrometers.
Quote from: jon_wade on November 28, 2025, 09:51:38 AMI obviously would like to move to a new instrument - but, if I were honest, I am struggling to see what the utility and business case is for users in the next decade. At best I can see the return of national centres given the financial pressures on research funding worldwide, especially in the earth and planetary sciences. I'd obviously like to be wrong.....
Well you're not completely wrong. Business models matter and the days of a single faculty buying (and maintaining!) an instrument of this class is simply no longer feasible. Which again, is one reason why we built a centralized facility at Oregon:
https://camcor.uoregon.edu/
The fact is this center was designed so we can perform *for profit* activity. We actually bring in 80% of our income with 20% of our billable hours. Because we charge industry 10x what we charge faculty and students.
It's now only academically relevant which is the same thing.
Most questions that are asked by industrial users in revenue generating sectors can be answered by other techniques cheaper and faster. Alloys can be identified by spark OES or XRF. Microanalysis is done more easily and at massively lower doses using EDS. Even mineral distribution and the like are now solidly the domain on SEM and automated mineralogy. Soon even for major and trace analysis you'll probably see the market lean towards LA-ICP-MS and combined LIBS and people just not caring that it's destructive.
The only places where EPMA remains relevant is in trace analysis in academic geology and possibly in the nuclear sector. I'm still not sure how well EDS detectors deal with radioactive samples, but I'm reasonably certain a WDS would cope better.
If you're looking for ways to save the EPMA it needs to become something that bolts on to an SEM. That means spectrometer geometries that are more adaptable to flexible mounting strategies and some way of doing absolute positioning in the chamber without colinear light optics. Maybe an offset rangefinder.
EPMA won't go away as long as there's some government lab out there with deep pockets willing to pay for bespoke equipment, but it will become more expensive in real terms for no marginal gain in capability as time goes on.
Quote from: Jacob on December 12, 2025, 08:37:47 AMThe only places where EPMA remains relevant is in trace analysis in academic geology and possibly in the nuclear sector. I'm still not sure how well EDS detectors deal with radioactive samples, but I'm reasonably certain a WDS would cope better.
I would argue that as long as SEM people using EDS refuse to utilize standards for major element quantitative analysis, WDS EPMA will still be useful.
Unless one only needs +/- 30% accuracy... and then I guess EDS is good enough ;D
https://smf.probesoftware.com/index.php?topic=302.msg2890#msg2890
Quote from: Probeman on December 12, 2025, 09:03:58 AMQuote from: Jacob on December 12, 2025, 08:37:47 AMThe only places where EPMA remains relevant is in trace analysis in academic geology and possibly in the nuclear sector. I'm still not sure how well EDS detectors deal with radioactive samples, but I'm reasonably certain a WDS would cope better.
I would argue that as long as SEM people using EDS refuse to utilize standards for major element quantitative analysis, WDS EPMA will still be useful.
Unless one only needs +/- 30% accuracy... and then I guess EDS is good enough ;D
https://smf.probesoftware.com/index.php?topic=302.msg2890#msg2890
That's kinda the thing. "Good enough" won and nobody noticed or cared. Your next "microprobe" might just be a normal SEM, a rockin' EDS, a set of standards, and DTSA-2. It's literally a quarter of the cost with cash left over for a shitty parallel beam WDS or the Oxford one to check that box. Is it as good? No. Is it as good per dollar? Yes. Way better, in fact.
Quote from: Jacob on December 12, 2025, 10:43:47 AMQuote from: Probeman on December 12, 2025, 09:03:58 AMQuote from: Jacob on December 12, 2025, 08:37:47 AMThe only places where EPMA remains relevant is in trace analysis in academic geology and possibly in the nuclear sector. I'm still not sure how well EDS detectors deal with radioactive samples, but I'm reasonably certain a WDS would cope better.
I would argue that as long as SEM people using EDS refuse to utilize standards for major element quantitative analysis, WDS EPMA will still be useful.
Unless one only needs +/- 30% accuracy... and then I guess EDS is good enough ;D
https://smf.probesoftware.com/index.php?topic=302.msg2890#msg2890
That's kinda the thing. "Good enough" won and nobody noticed or cared. Your next "microprobe" might just be a normal SEM, a rockin' EDS, a set of standards, and DTSA-2. It's literally a quarter of the cost with cash left over for a shitty parallel beam WDS or the Oxford one to check that box. Is it as good? No. Is it as good per dollar? Yes. Way better, in fact.
It's not "good enough", it's that 99% of SEM users don't know better. Do you know how I know that? It's because they publish their standardless EDS results with 6 significant digits! That is ignorance, not just "good enough".
That is why we're trying to develop a global set of standards which will help with SEM/EDS, but again, the main problem is that most people are lazy and if the vendor software makes it more painful to use standards, most people will do the easy thing even if it's crap.
Call me a radical, but I am firmly against crap science...
I used to joke that the main advantage of WDS over EDS, is that with WDS one MUST use standards! :)
I am shocked to discover that people are out there doing poor science.
But seriously, for the people that care they'll figure it out. For the problems that matter (boosting wafer yield by a tenth of a percent, stopping corrosion on bridges, etc) they'll figure it out. Microprobe just isn't the go-to technique anymore for solving these types of problems. You can rail against it but it's not changing.
The global set of standards thing is a bit of a red herring. Pure metal standards are good enough to drastically improve the quality of analysis across the board and they're already available.
Maybe sell a Probe Software junior edition for cheap that's EDS only if you want to push things in the direction of standards?
Quote from: Jacob on December 14, 2025, 09:11:21 AMBut seriously, for the people that care they'll figure it out. For the problems that matter (boosting wafer yield by a tenth of a percent, stopping corrosion on bridges, etc) they'll figure it out
Then again, maybe not.
Currently vendors estimate that 98 to 99% of SEM EDS analyses are performed standardless, so I guess at least that means there's plenty of room for improvement. :D
I do continue to have hope that creating a set of global standards, as Will Nachlas and others are working on, will help in this regard. It will certainly help those that care about the accuracy of microanalysis.
Quote from: Jacob on December 14, 2025, 09:11:21 AMMicroprobe just isn't the go-to technique anymore for solving these types of problems. You can rail against it but it's not changing.
Well that's one opinion I guess.
Look, if people decide they don't care about accuracy or precision well, maybe you're right. But I don't "rail against", I educate. There's always room for improvement, and I include myself in this regard.
Quote from: Jacob on December 14, 2025, 09:11:21 AMThe global set of standards thing is a bit of a red herring. Pure metal standards are good enough to drastically improve the quality of analysis across the board and they're already available.
I agree and disagree.
Yes, the use of simple pure metal standards would "dramatically improve" the current situation over not using any standards with EDS. And maybe "dramatic" improvement indicates the current situation is possibly not "good enough".
I disagree in that there's plenty of elements that cannot be utilized as pure elements. Alkalis, halogens, alkali earths, rare earths, light elements, etc., etc.
And yes EDS, with it's much poorer spectral resolution, is less sensitive to chemical state than WDS, but some elements will still benefit from using the pure oxide, nitride, carbide or boride, as opposed to the pure metal, especially light elements and also many other elements as mentioned above.
Quote from: Jacob on December 14, 2025, 09:11:21 AMMaybe sell a Probe Software junior edition for cheap that's EDS only if you want to push things in the direction of standards?
I've considered that, but there's an easier way...
I once went around to the various EDS vendors and suggested that if they really wanted to improve the scientific accuracy of their quantitative analyses, maybe they should get rid of the standardless "quant" method.
The reply was invariably: "you want us to make our customers get standards?"
And my reply was always: "yes". :D
Speaking of quant EDS: I've been working for a couple of years now on a follow-up to DTSA-II.
My goal: Removing as much friction as possible when making standards-based analyses with EDS. While DTSA-II does produce accurate results, its workflow is clumsy and sub-optimal. By integrating a database and providing a basic but comprehensive standard block suited to EDS analysis, it is possible, with current generation detectors, to collect and reuse standard spectra for extended periods of time. The result is a really accurate and productive tool for point spectra and X-ray spectrum images.
I wouldn't expect a large audience for this software as most people today think of EDS as qualitative-only. But there is a core (mostly frustrated WDS people) who would appreciate it.
Currently, the tool is "command line only." I find it extremely productive as such, but I would imagine the learning curve is more than most people would accept. I find the only reason you need an interactive (GUI) tool is to perform 'qual'. Otherwise a command-line tool that outputs results as CSV/Markdown/Text/LaTeX is excellent for volume work and for importing into the next tool in your analysis pipeline. It also outputs plotted spectra as PDF/PNG/SVG for integration into reports. (PDF is great for LaTeX)
I am working on a basic GUI but, IMHO, GUI development is tedious and I frequently get sidetracked adding a new feature to the command-line tool.
This has been a side project (at home in my spare time). It is not open source and I'm unlikely to give it away for free like DTSA-II. (I don't think I can make much money from it but it would be a nice side project to remain in this community for retirement.)
The advent of Free Electrons by the provision of a FE gun should have made EPMA so much more useful and powerful. But... we have stuck to the age old model of hourly costing so that the EPMA sits idle most nights. Those with a tame EPMA within their empires will realise the electrons come off the gun anyway and utilise the machine overnight.
I have one of the most used EPMA's and it maps most nights. Data for free with excellent S/N, no deadtime issues and overlap issues - don't make me laugh.
When you are doing trace level mapping and forced to do bkg corrected mapping the EPMA is the only way to get the high spatial and spectral resolution - rebirth is just around the accounting corner.
There's some hope in recent interest regarding critical metals. These happen to be heavier elements with many overlapping lines that even XRF instruments struggle with. LAICPMS does not have the spatial resolution. WDS is ideal for this, and many commercial clients are interested in these things now.
In some cases they just want pretty maps, so we don't even calibrate with standards. Just map on the peak, and avoid EDS-style interferences.