I just finished assembling and calibrating an Amptek Mini-XRF constructed using their X-123 detector/MCA and a Mini-X Xray source (Ag target). I was able to identify elements from Ca up, but am having difficulty with the lighter elements (F - K). Amptek suggests using the unit in a vacuum to reduce/eliminate air absorbtion. The detector is sensitive down to F. Looks like I'll have to construct a vacuum chamber to house the whole unit. Fortunately, it is only 8-10 inches across and about 2 inches high. The detector is very sensitive and I got excellent ED peaks for a sample of iron ore that was sub-milligram in size. I hope to be able to chemically identify tiny crystals when I get a vacuum chamber constructed. http://www.mindat.org/forum.php?read,100,188745,188745#msg-188745 Wed, 19 Jun 2013 12:54:17 +0000 Phorum 5.2.15a http://www.mindat.org/forum.php?read,100,188745,228185#msg-228185 http://www.mindat.org/forum.php?read,100,188745,228185#msg-228185
Yes, they have several models, some of which use the Amptek Peltier Cooled Diode. The lower cost XRF's use gas proportional counters as the detector. The major cost would be the detector and x-ray tube.]]> Bob Rock Analytical Techniques Mon, 27 Jun 2011 00:22:05 +0000 http://www.mindat.org/forum.php?read,100,188745,228183#msg-228183 http://www.mindat.org/forum.php?read,100,188745,228183#msg-228183
Just a guess, but when I looked into these units a few years back, they used imported Amptek Peltier cooled diodes for the sensor. Most of the cost of these XRF's is likely those same diodes. Wish the Chinese would start manufacturing the things, then we might see a drop to several hundred rather than several thousand dollars.]]> Henry Barwood Analytical Techniques Sun, 26 Jun 2011 23:47:52 +0000 http://www.mindat.org/forum.php?read,100,188745,228182#msg-228182 http://www.mindat.org/forum.php?read,100,188745,228182#msg-228182
I am not sure what you are wanting the XRF for? The XRF I have is advertised on the Internet as a Gold Testing Unit for around US$7000.00. I purchased direct from the Chinese. The model number is EXF7200.

The XRF comes with templates for quantitatively determining gold, silver, platinum and palladium. It will also detect other elements from Ti to Bi qualitatively. These can be identified by looking up their energies in the periodic table. I wrote my own templates for identifying the other elements. I might add an article on this XRF unit later.]]> Bob Rock Analytical Techniques Sun, 26 Jun 2011 23:37:15 +0000 http://www.mindat.org/forum.php?read,100,188745,228170#msg-228170 http://www.mindat.org/forum.php?read,100,188745,228170#msg-228170 Gene Analytical Techniques Sun, 26 Jun 2011 19:53:39 +0000 http://www.mindat.org/forum.php?read,100,188745,228169#msg-228169 http://www.mindat.org/forum.php?read,100,188745,228169#msg-228169 Gene Analytical Techniques Sun, 26 Jun 2011 19:52:27 +0000 http://www.mindat.org/forum.php?read,100,188745,227891#msg-227891 http://www.mindat.org/forum.php?read,100,188745,227891#msg-227891 Bob Rock Analytical Techniques Thu, 23 Jun 2011 04:32:25 +0000 http://www.mindat.org/forum.php?read,100,188745,227846#msg-227846 http://www.mindat.org/forum.php?read,100,188745,227846#msg-227846 Henry Barwood Analytical Techniques Wed, 22 Jun 2011 17:43:22 +0000 http://www.mindat.org/forum.php?read,100,188745,227840#msg-227840 http://www.mindat.org/forum.php?read,100,188745,227840#msg-227840 Bob Rock Analytical Techniques Wed, 22 Jun 2011 16:19:50 +0000 http://www.mindat.org/forum.php?read,100,188745,223943#msg-223943 http://www.mindat.org/forum.php?read,100,188745,223943#msg-223943 Henry Barwood Analytical Techniques Tue, 17 May 2011 02:49:16 +0000 http://www.mindat.org/forum.php?read,100,188745,223853#msg-223853 http://www.mindat.org/forum.php?read,100,188745,223853#msg-223853 Bob Rock Analytical Techniques Mon, 16 May 2011 11:18:58 +0000 http://www.mindat.org/forum.php?read,100,188745,221373#msg-221373 http://www.mindat.org/forum.php?read,100,188745,221373#msg-221373
I would love to be able to have an SEM/EDS machine at my disposal, but I teach at a "second tier" university with very limited research funds. The mini-XRF will likely be as close as I get to one.

My experiences with fixing SEM's was entirely negative and I doubt I have enough time and resources left to tackle that kind of a project.

I do hope to have an XRD operational by summer. I like using a powder camera for mineral identification. I've worked with them so much that they hardly seem time consuming and they do provide reasonably definitive identification of a mineral species. If you happen to have EDS/WDS data also that is confirmation of the identify of the mineral.

At one time I had a micro XRF that Phillips/Norelco made for their vacuum spectrograpth. Left it behind during a move and it is likely in a landfill somewhere. Wish I had it now. It did pretty good spot analyses, and was WDS.

Henry]]> Henry Barwood Analytical Techniques Fri, 22 Apr 2011 23:12:25 +0000 http://www.mindat.org/forum.php?read,100,188745,221319#msg-221319 http://www.mindat.org/forum.php?read,100,188745,221319#msg-221319
Every university has pallet loads of used vacuum pumps. Many are perfectly good, and can achieve adequate vacuum to detect sodium without the need for a diffusion pump. The pallets of vacuum pumps here at the U.W. in Seattle often sell for less than $100. I have some good pumps that I would give away.

I have an old Kevex XRF unit. Its vacuum chamber is a sliding drawer about 2"x1"x3". The beam is fat, but a sample holder could be made out of plastic to eliminate stray spectra.

A larger chamber is easy to build out of thick plexi-glas, and using a fluorescent target you could see your beam diameter and location.

I still believe that eventually Bob and Henry will buy an old SEM and interface their Amptek detectors.

There is no work-around for the image and analysis resolution obtained by an SEM.

I also have some SEMs that I would give away. They all need a little work, but that's fun of it.]]> Bart Cannon Analytical Techniques Fri, 22 Apr 2011 12:16:31 +0000 http://www.mindat.org/forum.php?read,100,188745,220288#msg-220288 http://www.mindat.org/forum.php?read,100,188745,220288#msg-220288
I have scanned about 30 reference samples of elements, pure analytical reagents with known concentration.

I have the following options for calculating concentrations:

1. Net Areas
2. Gross Areas
3. Pure spectrum (single element)
4. Pure spectrum (multi element)

My understanding is that
net areas calculates the areas under peaks of interest and converts them to concentration
pure spectrum (single element) uses some type of k ratio calculation

I am not sure what gross area and pure spectrum (multi element) are for

So far, it works great for qualitative and semi quantitative elements. I have not done enough tests for evaluating quantitative results

What calculation method would you guys use for this type of spectrometer for quantitative analysis?]]> Bob Rock Analytical Techniques Wed, 13 Apr 2011 08:53:34 +0000 http://www.mindat.org/forum.php?read,100,188745,219112#msg-219112 http://www.mindat.org/forum.php?read,100,188745,219112#msg-219112 Henry Barwood Analytical Techniques Fri, 01 Apr 2011 20:57:51 +0000 http://www.mindat.org/forum.php?read,100,188745,219021#msg-219021 http://www.mindat.org/forum.php?read,100,188745,219021#msg-219021 Bob Rock Analytical Techniques Fri, 01 Apr 2011 06:49:44 +0000 http://www.mindat.org/forum.php?read,100,188745,218715#msg-218715 http://www.mindat.org/forum.php?read,100,188745,218715#msg-218715 Only templates for Au, Ag, Pt and Pd are provided. I am adding other elements using pure reference samples. The software handles the calculations, but is a little tricky to set up correctly.]]> Bob Rock Analytical Techniques Wed, 30 Mar 2011 05:54:58 +0000 http://www.mindat.org/forum.php?read,100,188745,218249#msg-218249 http://www.mindat.org/forum.php?read,100,188745,218249#msg-218249 Bob Rock Analytical Techniques Sat, 26 Mar 2011 06:42:59 +0000 http://www.mindat.org/forum.php?read,100,188745,218224#msg-218224 http://www.mindat.org/forum.php?read,100,188745,218224#msg-218224
You might try putting baggie over it and flooding the detector with Helium. Would improve the low-Z detection limit.]]> Henry Barwood Analytical Techniques Sat, 26 Mar 2011 01:10:46 +0000 http://www.mindat.org/forum.php?read,100,188745,218217#msg-218217 http://www.mindat.org/forum.php?read,100,188745,218217#msg-218217 Bob Rock Analytical Techniques Fri, 25 Mar 2011 22:24:17 +0000 http://www.mindat.org/forum.php?read,100,188745,215923#msg-215923 http://www.mindat.org/forum.php?read,100,188745,215923#msg-215923
I actually used some research funds to purchase the Amptek parts. It was a one-time allocation that I will not see again. The collimator on the X-ray source is 2 mm. They have narrower ones, but for my use, 2 mm was sufficient.

I wish I had your optimism about SEM/EDS units. I've worked with energy and wavelength dispersive analysis for 30+ years and a good technician is essential to good results! I do agree that modern "service" engineers are little more than board changers.]]> Henry Barwood Analytical Techniques Fri, 04 Mar 2011 20:06:45 +0000 http://www.mindat.org/forum.php?read,100,188745,215870#msg-215870 http://www.mindat.org/forum.php?read,100,188745,215870#msg-215870
I would guess that you bought the AMPTEK x-ray gun, the AMPTEK detector and pre-amp and the AMPTEK pulse processor and multichannel analyzer.

I expect that you probably paid $16K. Am I close?

I would love to have that system, but it's more than I can afford as an accessory to my other gear.

Do you know what the x-ray spot size will be? I think you would be lucky if it was as small as 200 microns.

Knowing your passion for mineral analysis, I think that you will probably end up with an SEM and EDS system eventually.

When I bought my first old ARL EMX-SM from the first moon rock era, I knew nothing about electronics and vacuum systems. I found a guy from Boeing to teach me about vacuum, and another guy from Boeing to show me how to adjust the electron beam and tune the wavelength dispersive X-ray spectrometers. I think the training cost about $700. I trained myself in electronics, vacuum and x-ray detectors. I've never had a service engineer in my lab since 1984.

You could do the same, and you could get a working SEM and EDS system for less than $3K.

I would be happy to give you some over the phone help, though I am sure that you could find a guy in your area for some inexpensive in the lab help.

There are many labs getting rid of their older SEMs in order to have state of the art instruments that have computer controlled everything.

The modern insturments require annual licenses, and can't really be repaired inexpensively since they are full of proprietary control boards, and there is a huge turnover in manufacturer take-overs of existing SEM companies. Service engineers on modern gear pack around large boards and swap them out to find the fix. Costs about $4K per board even if the fault is a 20 cent transistor. The service call will be $5K.

I know of many AMRAY 1200 SEMs from 1974 to 1980 which are still running.

In fact I have one in my garage with a PGT detector. Price ? $1,000 plus shipping. But you could surely do better than that locally.

Please keep me posted on your system. I'm quite interested, and if some of my current gear blows out beyond cheap repair, AMPTEK is certainly an option I will investigate for replacement.]]> Bart Cannon Analytical Techniques Fri, 04 Mar 2011 12:27:12 +0000 http://www.mindat.org/forum.php?read,100,188745,215836#msg-215836 http://www.mindat.org/forum.php?read,100,188745,215836#msg-215836 Henry Barwood Analytical Techniques Fri, 04 Mar 2011 00:44:26 +0000 http://www.mindat.org/forum.php?read,100,188745,215375#msg-215375 http://www.mindat.org/forum.php?read,100,188745,215375#msg-215375
They were located in Santa Clarita in 1988, and have been out of business since. Advanced Microbeam in Vienna, Ohio have taken over the service and modernization of ARL probes.

I got the probe operating in the EMTEK office and it sold to Western Michigan University in Grand Valley, Michigan. Kevin Cole was to be the user. I'm not sure if they ever got it running at their place.

I started building a large chamber vacuum based, x-ray induced XRF unit a few years ago. X-ray induced XRF has a much lower minimum detection limit than than electron induced XRF. I was tasked to provide a benign analytical circumstance to get some x-ray spectra from the spear point lodged in 9,300 year old Kennewick Man's ilium. The project went nowhere because the tribe's and the conservatuers were afraid the vacuum would disintegrate the bones.

I proved that there would be no harm by analyzing similar old bones in an EDAX Eagle III x-ray microprobe. This is an expensive piece of gear. It has x-ray optics that produce a 50 micron x-ray beam, a micrscope to locate the beam area and a precise stage translator.

It has helium, air, and vacuum paths. The helium path gets you down to silicon, but to get down to sodium you need a vacuum path.

I would not recommend using Henry's approach. For what he is going to pay you could buy a pretty good SEM with a liquid nitrogen based EDS system and ten years of liquid nitrogen. Plus you'd get a working vacuum system with sodium or better detection, and x-ray lateral resolution of one or two microns, and SEM quality imaging.

I've been down this road.

And Rock, thanks for loaning me your van and your best "toadie" for the EMTEK project ! I am forever in your debt.]]> Bart Cannon Analytical Techniques Mon, 28 Feb 2011 04:23:26 +0000 http://www.mindat.org/forum.php?read,100,188745,213293#msg-213293 http://www.mindat.org/forum.php?read,100,188745,213293#msg-213293 Henry Barwood Analytical Techniques Thu, 10 Feb 2011 02:57:59 +0000 http://www.mindat.org/forum.php?read,100,188745,212901#msg-212901 http://www.mindat.org/forum.php?read,100,188745,212901#msg-212901 Angela Rostan Analytical Techniques Fri, 04 Feb 2011 00:54:09 +0000 http://www.mindat.org/forum.php?read,100,188745,210501#msg-210501 http://www.mindat.org/forum.php?read,100,188745,210501#msg-210501
The version I have runs under Windows XP and will accept a variety of input formats. I will not be able to retrieve it from my office until at least Tuesday (it is installed on a lab laptop). Glad you could get the older Fortran version running. A little Unix code is about hte best I can manage!]]> Henry Barwood Analytical Techniques Sun, 16 Jan 2011 03:55:43 +0000 http://www.mindat.org/forum.php?read,100,188745,210441#msg-210441 http://www.mindat.org/forum.php?read,100,188745,210441#msg-210441 lilo Analytical Techniques Sat, 15 Jan 2011 15:21:31 +0000 http://www.mindat.org/forum.php?read,100,188745,210410#msg-210410 http://www.mindat.org/forum.php?read,100,188745,210410#msg-210410
You can post to me directly at lilo49er@y7mail.com

lilo]]> lilo Analytical Techniques Sat, 15 Jan 2011 08:38:03 +0000 http://www.mindat.org/forum.php?read,100,188745,210237#msg-210237 http://www.mindat.org/forum.php?read,100,188745,210237#msg-210237
I am still constructing the vacuum enclosure. It has gone through a couple of design changes, and is now a small chamber that fits on the end of the X-ray and the Detector. Since the two units are of differing diameters and shapes, and are set at a 45 degree angle, it has been fairly difficult to construct. I hope to have the first prototype assembled and ready for testing in a few weeks.

I used thin Lead sheet as a shielding material and it worked quite well.

I'll have to dig up the URL of the NIST software and see if I can send it to you.]]> Henry Barwood Analytical Techniques Thu, 13 Jan 2011 23:16:19 +0000 http://www.mindat.org/forum.php?read,100,188745,210218#msg-210218 http://www.mindat.org/forum.php?read,100,188745,210218#msg-210218
Can you post the link to the NIST software?

Keen to know if the vacuum chamber worked for the light elements?]]> lilo Analytical Techniques Thu, 13 Jan 2011 20:09:32 +0000