XRF Wiki
Welcome to the XRF Wiki. This Wiki is a repository of information contributed by members of [email protected]. Members can view and edit the pages. The pages are currently not viewable by the public. The pages below represent a rough overview of the technology and techniques associated with X-Ray Florescence Spectroscopy as well as serving as a place for members to organize the spectra that they have contributed to the forum.?
As a starting point, the pages will be populated by information taken from member posts from the past few years - with references/attribution. Perhaps in time, these pages can be edited by members to make them more complete and less choppy. Members can also edit this page, making the structure of the content more organized.?
Pages can contain information about a particular topic, links to relevant resources (such as manuals, research papers, etc.), links to relevant forum discussions on the topic, book titles, or anything that might be useful.
What follows is very much a work in progress.
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Adding to the Wiki
For those unfamiliar with the Wiki phenomenon, it is basically a user editable encyclopedia. The idea is that there are pages with different articles, which the user can read and also choose to edit if desired. If a piece of information is incorrect, a link outdated, or the presentation choppy or unclear, the user can just click "Edit Page" at the bottom and then fix the mistake. There is also a "Page History," so if you a user were to make a mistake or maliciously destroy a page (which wouldn't happen here) an editor can come along and restore the page to a previous version.?
If you have used MediaWiki (the engine that runs behind the scene of Wikipedia.org) you will be familiar with a certain style of creating an article. There are tags that one uses to change the formatting of the parts of the article. The Wiki on Groups.io uses a different background engine and so the standard MediaWiki syntax does not apply here. Rather, the page is edited using the same tools as one would use to compose a message on the forums. If you are a programmer or someone who likes using the tagged syntax directly, you can access the underlying page source code, be activating the advanced editing toolbar (the icon with three lines on the far right of the basic toolbar) and then clicking on the source code icon <> on the far right of the Advance Editing Toolbar. You will immediately notice that the underlying source code is HTML. Most things can be done just by using the various icons, but advanced features like table can only be implemented by manually writing the source code. (Although there are website available that will generate the source code for you through a graphical interface.)
Here are some useful resources from Groups.io:?
Wiki Guide for Users and Editors
Message Composition Tips and Tricks
Overview of XRF
X-Ray Florescence vs. X-Ray Diffraction
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Hardware
This section describes the hardware used for XRF. We will describe the basic theory of operation of each stage in the processing tool chain and then present different commercial systems that are available as these systems are often integrated together.
[Editor note: General theory needs to be in an independent page separate from specific manufacturer information.
[Editor note - question: Should this be arranged by category, e.g detectors, preamps, etc or by manufacturer with the manufacturers product line on one page. Perhaps it's best to put a list of products with theory but the details of the products on a manufacture page...]
Detectors?- what's available, theory of operation, tradeoffs
Detector Cooling?- keeping detectors cool to avoid thermal noise and keeping the TEC from overheating
Preamps?- theory of operation, brief summary of what out there (and what not to do - such as trying to use a PMT preamp for a SiPIN diode...)
Pulse Processing Theory - high level overview of the stages of going from detector pulse to channel peaks on the computer
Commercial Systems - many commercial systems are integrated so it seems to make sense to present, for example all Amptek products together. [question: are their other affordable integrated systems besides Amptek?]
Amptek XRF System
Activation Sources - what do you use to make the sample fluoresce (that's within the amateur budget and doesn't require special licensing)
Software
- Device Control Software - what do you use to collect the data from the detector system
- XRF Analysis Software - what do you use to analyze the data, especially for quantitative measurements (composition percentages, thin film measurement)
- Free Software Tools
Note: there may be software packages that possess some or all of these characteristics.
Materials Spectra
Metals Spectra
Historic/Archeological Spectra
Reference Materials Spectra
Household Objects Spectra
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Resources
Videos
Articles
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Non-XRF Techniques
Gamma Spectroscopy
Raman Spectroscopy
FTIR - Fourier Transform Infrared Spectroscopy
Atomic Emission Spectroscopy
Inductively Coupled Atomic Emission Spectroscopy
Spark Emission Spectroscopy
Atomic Absorption Spectroscopy
LIBS - Laser Induced Breakdown Spectroscopy
Photoacoustic Spectroscopy
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Re: Trinitite
Refer message 766 and 772
Analyzing Trinitite with emphasis on the Uranium and Neptunium Ly1 peaks. Preparation; First I did the analysis of Uranium K and L lines mentioned in message #766. Then I did same for an Am-241 source. Next the two were overlaid and notations made to show the subtle but measurable shift in the La and Lb lines and the more noticeable shift in the Ly1 lines.(y= gamma, third letter in Greek). So all that is needed to finish the experiment is a good scan of Trinitite on the Si-PIN with the same settings as the? Am-241, and those two graphs overlaid. This one happens to be some Red Trinitite, as the big green one is in another chamber being tested on a long 24 hour run. Why does it matter if the lines are U or Np? It is just one step in testing Trinitite for Plutonium.? we already know Am-241 is a decay product of Pu-241, and there are only 3 easy ways to get Uranium X-Rays- 1:Decay of U-238, to the stage where U-234 is created 2: Deliberate XRFing Uranium, or unintentionally XRFing it by a random energy source. 3: Decay of Plutonium or one of its higher progeny to Uranium. Remember, natural decay induced X-Rays come from the daughter at the moment of creation, not from the parent. How many other ways can we test for the presence of Plutonium? Any species will do, as long as its half life is long enough for there to be some left. Hint: one way to at least make progress is Alpha Spectroscopy. My plans are to marry a silicon Alpha detector to an Amptek DP5 processor and hope for results. An external preamp is needed, I have those in NIM, discreet, removed from surplus equipment and in this ingenious device made by a company called The Nucleus. Equipment manufacturer by Spectrum Techniques today is so similar to other models made by The Nucleus that I suspect a link there. Geo>K0FF |
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Re: Testing for Cd in Zn Ore.
开云体育Geo, Sphalerite (ZnS) has an affinity to pick up a lot of different impurities. Here in southern Az Cd is common as one of those impurities. Try running some Sphalerites’ and see what you get. I also had some Cd in Galena (PbS) at 89 ppm with the Ag running 0.7% (234 oz/ton).? Dud From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Tuesday, February 18, 2020 7:37 AM To: [email protected] Subject: [XRF] Testing for Cd in Zn Ore. ? Thanks to member Steve D. in ALBQ NM for mentioning that Zn
ores are also a common source of? |
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Re: Trinitite
开云体育Geo, That dead time is pretty high. Its best to Set the tube ?current to keep the dead time around 10% or less than 35K cps. First shot should use full voltage then set the Kv’s ?to target the absorption edge of element range of interest? say about 1.5 the times the edge. Use filters for that edge to target the element of interest. ?Good luck sorting out Ba from decay, XRF and that in the soil. Dud ? ? From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Tuesday, February 18, 2020 1:28 PM To: [email protected] Subject: Re: [XRF] Trinitite ? Now my largest green-glass Trinitite sample tests. |
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Re: Trinitite
开云体育
Some of the barium may be from Baratol, a barium nitrate/TNT mix that what used for the explosive lens for the device. Low velocity stuff.
Steve
From: [email protected] <[email protected]> on behalf of GEOelectronics@... <GEOelectronics@...>
Sent: Tuesday, February 18, 2020 2:28 PM To: [email protected] <[email protected]> Subject: Re: [XRF] Trinitite ?
Now my largest green-glass Trinitite sample tests.
Trying to determine the "best" settings to detect good XRF on the Si-PIN sensor: This test is?XRF by X-Ray tube at different kVp levels and current levels.Other tests will use AmX8 exciter and anything else I can think of. All the settings agree, there is considerable barium element present. Some is from Cs-137 beta decay (Ba-137m) and is responsible for the familiar 662 keV peak we all use for calibration. Some could be old fission products and some could have been in the soil before Trinity. A few different X-Ray setting results .mca attached. There should be enough data here to really determine the sweet spot for settings, taking into account peak broadenings, deadtime, and runtime. Geo>K0FF |
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Re: Trinitite
Now my largest green-glass Trinitite sample tests.
Trying to determine the "best" settings to detect good XRF on the Si-PIN sensor: This test is?XRF by X-Ray tube at different kVp levels and current levels.Other tests will use AmX8 exciter and anything else I can think of. All the settings agree, there is considerable barium element present. Some is from Cs-137 beta decay (Ba-137m) and is responsible for the familiar 662 keV peak we all use for calibration. Some could be old fission products and some could have been in the soil before Trinity. A few different X-Ray setting results .mca attached. There should be enough data here to really determine the sweet spot for settings, taking into account peak broadenings, deadtime, and runtime. Geo>K0FF |
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Re: Trinitite
more pics of the metallic Trinitite
This is the first CdTe in its chamber. The "lid" is a lead (Pb) Half-Brick that slides over the opening. This is a different CdTe, same as the first one, it has its own chamber too, but much smaller, only the sample and sensor portion of the probe goes into it. Usually one is set to run 0-200 keV the other one to 0-400 keV (max range). Both run at the same time, independently. The dots on the sample is a paint marker to identify the edge or surface being tested. Thanks to Al Shinn for that tip. Next post will be some XRF of the green glassy type of Trinitite- has anyone bothered to analyze the non radioactive elements present? Geo>K0FF |
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Re: Testing for Cd in Zn Ore.
Next a scan of the empty chamber, same parameters but without a sample inside.
Then the empty chamber "background with X-Ray ON" with the actual metal XRF together: RED is the empty chamber with X-Ray ON, the black ghost outline is same parameters but with the pure metal "stamp" in place. Obviously the Cd L lines can be excited and measured in a pure sample. What remains next is to see how well they stand out in an actual ore. Right now I am of a mind that looking for Cd in Zn ore will best be serviced with an isotopic rather than electron exciter source. Note the blue highlight is an ROI to indicate the area tat Cd L-lines occupy. Geo |
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Testing for Cd in Zn Ore.
Thanks to member Steve D. in ALBQ NM for mentioning that Zn ores are also a common source of?
Cd. Testing several species of ore here with the new emphasis on Cd has proved problematic. First the X-Ray hump from the tube is most intense right where Cd K line XRF is located, making it harder to pick out a weak peak there. Strong K peaks- no problem, as shown in one of the pictures to follow. So I tried looking for L peaks from Cd in? ore.? First steps are to use pure Cd metal to establish calibration points exactly for 3.2, 3.13, 3.31, 3.52, and 3.71kev. Then another XRF test of the empty chamber, with no samples inside, for the same time and exposure data. In all tests for this series, the 3 Al beam filters remain but the final collimator is removed to give a wide beam on the mineral tests to follow. The detector is an Amptek Si-PIN into the Amptek DP5-PC5 electronics stack, then USB to a notebook computer for control and storage. First the pure metal "stamp"r, X-Ray source set to 37kVp-25uA In the above, Ka, Kb are in perfect alignment and something is barely detected around 3 keV This rendition (LINEAR) shows how well the K lines are excited in the lighter elements, compared to their L lines. Geo |
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Re: Smithsonite with Uranium
开云体育
Cd commonly found in zinc ores, in this case probably present as the cadmium carbonate otavite. Zinc ores are the primary source of cadmium. Under UV, it has a very nice red fluorescence.
From: [email protected] <[email protected]> on behalf of Dude <dfemer@...>
Sent: Sunday, February 16, 2020 12:36 PM To: [email protected] <[email protected]> Subject: Re: [XRF] Smithsonite with Uranium ?
Geo, Big difference. Zn predominant some Fe, Pb, Cd (!) ?and possibly Cu. Where’s the Uranium? Dud ?
? ? ? ? ? ?
From: [email protected] [mailto:[email protected]]
On Behalf Of GEOelectronics@... ? On Sun, Feb 16, 2020 at 10:54 AM, Dude wrote: One could hardly call that a peak. This is going to need the x-ray source to see what’s there. Dud
Also are attached 2 .mca, the 5 second one for fun and the serious 90 second one for hidden details. Geo>K0FF ? |
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Re: Smithsonite with Uranium
开云体育Geo, Big difference. Zn predominant some Fe, Pb, Cd (!) ?and possibly Cu. Where’s the Uranium? Dud ? ? ? ? ? ? ? From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Sunday, February 16, 2020 9:58 AM To: [email protected] Subject: Re: [XRF] Smithsonite with Uranium ? On Sun, Feb 16, 2020 at 10:54 AM, Dude wrote: One could hardly call that a peak. This is going to need the x-ray source to see what’s there. Dud
Also are attached 2 .mca, the 5 second one for fun and the serious 90 second one for hidden details. Geo>K0FF ? |
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Re: Smithsonite with Uranium
On Sun, Feb 16, 2020 at 10:54 AM, Dude wrote:
This was cool. It was still running in the Gamma Spec chamber on the CdTe (no external exciter) so I stopped that count, moved it over to the XRF chamber and did a scan there with X-Ray tube and Si-PIN. That didn't take long, now the sample is back in the CdTe Gamma Spec chamber with the counting resumed. It's se for 24 hours, and will be finished shortly.? If anyone is familiar with CZT detectors (Cadmium-Zinc-Telluride), Amptek tried them for a short time a maybe 15 years ago. Their performance is excellent, but there were problems with the pulse shape ( I think). They soon switched to a better all around crystal, this one is just Cadmium-Telluride evidently. That's what is in the one chamber, we call it CdTe. It has good performance but not as good as Si-PIN, however, the CdTe carries that good performance up to much higher energies. It has lost no sensitivity at 100 keV and is very usable at 200 keV, and will go up to 400 keV max with my setup. In the XRF chamber is a Si-PIN detector, it is only to specs up to 25 keV and falls off the charts at 60 keV. Both technologies together give make a good combination I think. Now the XRF scan, note the scan time! Geo>K0FF
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