History of EPMA

[John Donovan]

I'm starting a new topic on the history of EPMA instruments and whatever else (software, people, etc.) that we want to talk about.

I'll start with some comments I made in response to Paul's mention of the shaw.dat k-ratio measurements which were apparently made on a MAC EPMA instrument long, long ago (fortunately the glass materials seem to still be available for new measurements).

Secondly. These measurements were made either on an ARL or the MAC probe and are subject to discussion regarding the instrumental stability in the case of the ARL (and takeoff angle not directly comparable to all other measurements made at 40 deg), and in the case of the MAC, non-normal beam incidence.

Since the ARL (SEMQ) was known for it's relatively high 52.5 deg takeoff angle (it was my first EPMA instrument when I arrived at at UC Berkeley), I'm guessing that the 38.5 degrees in the shaw.dat file means these measurements were done on a MAC probe?   I never saw one of these instruments myself, but if I google "MAC EPMA 38.5", the first search result returned is a talk by a guy named Paul Carpenter that gave a presentation at UofO in 2007 entitled "Electron-Probe Microanalysis: Instrumental Calibration, Standards, Quantitative Analysis, and Problem Systems":

http://epmalab.uoregon.edu/Workshop2/Carpenter_Oregon_Workshop_2007.pdf

It's only 118 slides long, so just a brief overview!  But in scanning through it I find results on slide 33 from the "Shaw" dataset measured on a MAC probe with a takeoff angle of 38.5 degrees.  I also found a link to a talk by John Fournelle that mentions the ARL EMX and MAC instruments from 1960 on slide 27:

www.geology.wisc.edu/~johnf/g777/ppt/10_Historical_Development.ppt

So I guess the EMX and MAC instruments were both made by ARL prior to their SEMQ model? 
john

Then Paul responded:

Thanks for reminding me about the MAC takeoff angle of 38.5 degrees. ARL did not mfg. the MAC probe. I think it stands for Materials Analysis Corporation.

Cheers,

Paul

[John Donovan]

Interesting.  It makes sense because I seem to remember now that the EMX probe was what ARL manufactured before the SEMQ. I think I even saw one once "in the wild", but can't remember where.  Does anyone know what takeoff angle the EMX had? 

Oregon may have had a MAC probe at one time.  After I arrived here I found a standard mount labeled "MAC standards".  I attach a drawing of the unusual layout below.

I'm more familiar with the subsequent history of the ARL SEMQ.  ARL was eventually bought by Bausch & Lomb, then split and sold off to Shimadzu and Advanced Microbeam. Shimadzu still sells new EPMA instruments in Japan (and China also). And they all have a 52.5 degree takeoff angle!
john

[John Donovan]

Then Anette responded:

Thanks for reminding me about the MAC takeoff angle of 38.5 degrees. ARL did not mfg. the MAC probe. I think it stands for Materials Analysis Corporation.
Paul

Yes, ARL did not manufacture the MAC probe but both came out of California apparently.

Wittry (2001, M&M) has much more information on the MAC probes, started in 1960 by Macres, who studied under Ogilvie at the MIT: "The competitive pressure forced on the industry by ARL with its high take-off angle, dictated that new instruments also have a high take-off angle. However, ARL’s inverted lens design was patented, so the MAC 400 achieved its 38.5-degree take-off angle by inclining the sample. Many of the leaders in the microprobe community strongly objected to the use of an inclined sample, as all the quantitative algorithms were either developed or substantiated using normal electron beam incidence on the specimen."

The University of Minnesota had a MAC probe at one time and I still have one spectrometer. For fun, here is a list of commercial sources for EPMA, coming out of an ASTM booklet from 1972.
Anette

[John Donovan]

Anette also wrote:

Does any one know what takeoff angle the EMX had?

It was also 52.5. I attached the Wittry paper that goes into all the details of the various spectrometer designs very nicely.

Oregon may have had a MAC probe at one time.  After I arrived here I found a standard mount labeled "MAC standards".  I attach a drawing of the unusual layout below.

Thank you for that layout! I have the exact same standard block! Except that the Be was killed before my time and then I killed the Mg and Mn metal unfortunately (and I am still looking for advice how to best re-polish this mount with a wide range of hardnesses).

Shimadzu still sells new EPMA instruments in Japan (and China also). And they all have a 52.5 degree takeoff angle!
john

They are also now on the American market. They have a "show room" Shimadzu Lab in Arlington, Texas (http://www.uta.edu/sirt/cefms/equipment/EPMA/EPMA.php) and someone bought one at least in Brazil (?).

Anette

[John Donovan]

Hi Anette,
How right you are about polishing a standard block with material hardnesses that range from from Al2O3 to Au!

The only person I can think to ask is Tim Teague at UC Berkeley.  He can polish anything.  He's close to retirement so don't hesitate to contact him!
john

[Karsten Goemann]

Hi John, could your MAC standard block also be from these guys:

http://www.macstandards.co.uk

[John Donovan]

Hi John, could your MAC standard block also be from these guys:

http://www.macstandards.co.uk

Hi Karsten,
Interesting.

I'll bet you are correct!
john

[Probeman]

You learn something new everyday!

One of my students asked why the element fluorine has the same root as fluorescence.  So we did some wiki searches and found that the word fluorescence comes from the Latin word "fluo" which means "to flow". 

https://en.wikipedia.org/wiki/Fluorescence

Now why would that be?  Well it turns out that the word fluorescence originates from the fact that the mineral fluorite was one of the first minerals that fluorescence was observed in!  Due to REEs apparently.  But why "to flow"?  Well, because fluorite was used as an early "flux" material (note the same root!) to remove oxides to lower the melting point when smelting ores and brazing metals.

https://en.wikipedia.org/wiki/Fluorite

And what does this have to do with fluorine?  Well of course fluorite was the first material from which fluorine was attempted to be isolated from (dangerous work!).

https://en.wikipedia.org/wiki/Fluorine

I wish I could have said that my high school Latin came in handy but I've forgotten more than I remember!
john

[Anette von der Handt]

Hi John, could your MAC standard block also be from these guys:

http://www.macstandards.co.uk

Hi Karsten,
Interesting.

I'll bet you are correct!
john

I don't think so. I have the exact same standard block (elements and layout) and it definitely predates MAC Ltd (founded in 1981 according to their webpage).

To my knowledge, it was a standard block that came with the MAC400 electron microprobe.

[Anette von der Handt]

When I was hunting for some old papers I found ads for various electron microprobes among the digitized content. Maybe someone else finds them as enjoyable as me. Mostly from the 60'ies and 70'ies.

First comes some ARL....

[Anette von der Handt]

and some more ARL....

[Anette von der Handt]

and then some Cameca. If anyone has anything else (JEOL, MAC etc) I would be very interested.

[Probeman]

Hi Anette,
These ads are a "blast from the past".  Thanks for posting them. 

I actually started on an ARL SEMQ at UC Berkeley in the mid 1980s as a mechanical technician.   It was an "interesting" instrument to say the least.  After a student managed to implode the vacuum chamber (let's call it an explosive depressurization, a long story), the electronics tech and I rebuilt it completely.  It was an education in EPMA I can tell you. It was after that when I realized the software needed to be improved. The rest is history as they say.

This isn't an ad, but it's the first Cameca MS85 EPMA (MS = MicroSonde) built in 1956 (see attached below- remember to login to see attachments).  We're both the same age...
john

[Anette von der Handt]

I forgot that I have one ad for JEOL too, unfortunately not for a microprobe but SEM. Still fun.

[Probeman]

I forgot that I have one ad for JEOL too, unfortunately not for a microprobe but SEM. Still fun.

100 angstroms resolution is 10 nm, so not bad for almost 50 years ago!