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 If a piece of information is incorrect, a link outdated, or the presentation choppy or unclear, the user can just click "Edit Page" at the bottom and then fix the mistake.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.)
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?]
"Interesting results, though not surprising.? Although a magnet won’t pick it up, not even a good neodymium magnet, a tiny neodymium magnet will “stick” to it, indicating that it is slightly magnetic."
Good tip and I'll try to remember to add that to my bag of tricks. What you describe might be "paramagnetic", the ability of an atom to display weak magnetism but only in the presence of a strong magnetic field. Titanium is one metal known for that, so is aluminum. Fe (iron) is of course a ferromagnetic atom, but when combined with another atom, becomes paramagnetic. molecule, for example FeO.
Please do try to look up your resistance readings, we can compare them to my results.
Aluminum is difficult to XRF in the amateur lab. But perhaps the magnetic susceptibility meter will give us a number.
Also the Mohs scratch test will give us a hardness, at least to the nearest whole number.
----- Original Message ----- From: Ken Sejkora <kjsejkora@...> To: [email protected] Sent: Thu, 30 Jan 2020 07:42:20 -0500 (EST) Subject: Re: [XRF] Ken's "Mystery Wire"
Thanks for scanning the wire, Geo.? Interesting results, though not surprising.? Although a magnet won’t pick it up, not even a good neodymium magnet, a tiny neodymium magnet will “stick” to it, indicating that it is slightly magnetic.? As you’ve ascertained, it is very hard, to the point it is difficult to cut it with wire cutters.? Well, at least, much more difficult than similar gauge iron or steel wire.
?
I pulled out a cheap micrometer (0.05 mm resolution), and the diameter comes out somewhere between 0.95 and 1.00 mm, or roughly 18-gauge.? Assuming a diameter of 0.975 mm, or 0.0975 cm, the cross-sectional area is 7.47E-3 cm^2.? A 10-cm piece of the wire would have a volume of 0.0747 cm^3, and has a mass of 0.65 grams.? That would equate to a density of 8.7 g/cm^3.? For comparison, here’s a table of the densities of the various elements that showed up in Geo’s XRF scan:
Cr:? 7.19 g/cm^3
Fe:? 7.88 g/cm^3
Ni:? 8.90 g/cm^3
Cu:? 8.92 g/cm^3
Mo: 10.22 g/cm^3
Ru: 12.41 g/cm^3
Sn:? 7.29 g/cm^3
?
It is moderately resistive as well, though nowhere as resistive as nichrome.? Many years ago I made up a jig consisting of a regulated DC voltage source feeding a chain of a 3-ft chunk of the wire in series with a 1% 100-ohm resistor.? I had a digital multimeter in the chain measuring the total current flowing through the series circuit, and then used another digital multimeter to measure the voltage across each of the individual ‘resistors’ in the circuit.? It was easy enough to use Ohm’s Law to solve for the “unknown” resistance represented by the 3-ft length of “mystery wire”…? R = E ÷ I.? I don’t remember the results now, but perhaps I’ll try to cobble the setup together again and repeat the experiment.? If I get the chance, I’ll report the results here.
Member Ken S sent in a wire labeled "Mystery Wire".
It is silver in color, very hard but not springy. Non magnetic. Extremely light for its volume. Many more tests to be done, but XRF was easy, and based on the elemental makeup my best guess as of today is one of the super alloys under ASTM B649-17
ASTM B649 - 17
Standard Specification for Ni-Fe-Cr-Mo-Cu-N Low-Carbon Alloys (UNS N08925, UNS N08031, UNS N08034, UNS N08354
Small mass, non magnetic even though Fe is major, low Ni content, low Cu content. Not a Nicrome, maybe an Alchrome? Will test further, hardness, electrical resistivity, thermal conductivity,? radioactivity etc.
Thanks for scanning the wire, Geo.? Interesting results, though not surprising.? Although a magnet won’t pick it up, not even a good neodymium magnet, a tiny neodymium magnet will “stick” to it, indicating that it is slightly magnetic.? As you’ve ascertained, it is very hard, to the point it is difficult to cut it with wire cutters.? Well, at least, much more difficult than similar gauge iron or steel wire.
?
I pulled out a cheap micrometer (0.05 mm resolution), and the diameter comes out somewhere between 0.95 and 1.00 mm, or roughly 18-gauge.? Assuming a diameter of 0.975 mm, or 0.0975 cm, the cross-sectional area is 7.47E-3 cm^2.? A 10-cm piece of the wire would have a volume of 0.0747 cm^3, and has a mass of 0.65 grams.? That would equate to a density of 8.7 g/cm^3.? For comparison, here’s a table of the densities of the various elements that showed up in Geo’s XRF scan:
Cr:? 7.19 g/cm^3
Fe:? 7.88 g/cm^3
Ni:? 8.90 g/cm^3
Cu:? 8.92 g/cm^3
Mo: 10.22 g/cm^3
Ru: 12.41 g/cm^3
Sn:? 7.29 g/cm^3
?
It is moderately resistive as well, though nowhere as resistive as nichrome.? Many years ago I made up a jig consisting of a regulated DC voltage source feeding a chain of a 3-ft chunk of the wire in series with a 1% 100-ohm resistor.? I had a digital multimeter in the chain measuring the total current flowing through the series circuit, and then used another digital multimeter to measure the voltage across each of the individual ‘resistors’ in the circuit.? It was easy enough to use Ohm’s Law to solve for the “unknown” resistance represented by the 3-ft length of “mystery wire”…? R = E ÷ I.? I don’t remember the results now, but perhaps I’ll try to cobble the setup together again and repeat the experiment.? If I get the chance, I’ll report the results here.
Member Ken S sent in a wire labeled "Mystery Wire".
It is silver in color, very hard but not springy. Non magnetic. Extremely light for its volume. Many more tests to be done, but XRF was easy, and based on the elemental makeup my best guess as of today is one of the super alloys under ASTM B649-17
ASTM B649 - 17
Standard Specification for Ni-Fe-Cr-Mo-Cu-N Low-Carbon Alloys (UNS N08925, UNS N08031, UNS N08034, UNS N08354
Small mass, non magnetic even though Fe is major, low Ni content, low Cu content. Not a Nicrome, maybe an Alchrome? Will test further, hardness, electrical resistivity, thermal conductivity,? radioactivity etc.
Great question Ken. I put together an experiment to at least answer some of it.
Characteristic X-Rays come from atoms heavier than? He when their electron shells are disturbed. Every electron in every atom has a distinct and unique energy level associated with it. We use that fact to capture X-Rays and analyze from whence they came The process involves several steps, fortunately the take place nearly instantaneously.
First we add energy to a target, some of which is absorbed by individual atoms making up that target. This energy can be in the form of X-Rays, as from an X-Ray tube, or X-Rays or Gamma Rays from a radioisotope as well as energetic particles like Beta and Alpha radiation of even an accelerated electron beam.
In our little niche of Physics, electromagnetic photons coming from the electron shells of atoms are generally called X-Rays, while otherwise identical electromagnetic photons generated within the nucleus of an atom are called Gamma Rays. We have long since abandoned the "Electromagnetic Spectrum Chart" that originally divided X-Rays into a low energy category, and Gamma Rays into the higher energy category. We know now that an X-Ray can have a higher energy than a particular Gamma Ray, so we chose our words based upon the modern definitions.
When we capture an X-Ray from our target it is analyzed in terms of precise energy level and counted in terms of? quantity over time. Those form a graph when plotted, from this graph we derive the individual patterns that identify all the elements.
That precise energy is then compared to charts to determine not only which orbital started the process, but which other orbital finished the process. Since all orbitals are unique, we also look for clusters that are related to a particular element. The more "clues" we find, the better can be our analysis of the atomic elements present.
So first we have to make sure our detectors are calibrated. For this experiment the calibration was done with the X-Rays generated by nearly pure copper foil and nearly pure zinc sheet metal (99.9+%).
Then we excite the metal and calibrate our instrument to that. First th Zinc, and notice the cursor is set to the main important zinc Ka line 8.64 keV:
Next the copper and notice the cursor remains fixed on the Zinc Ka Line: We'll leave it there when analyzing the penny? too..
Now load the penny into the chamber. Note the beam enters through a pinhole in the plate, from below, strikes the target, the newly created X-Rays proceed into the detector:
:
And finally the resulting scan of the penny. We expect it to show copper and also zinc. All the information needed is in this scan, but it may not be easy to interprete- we think we are seeing some copper and some? zinc:
Yes there is the zinc line, still under the cursor, but before we say what this is let's test the results further: The easist way to do that is place the penny's scan, the pure copper scan and the pure zinc scan all on the same graph at the same time.By "ghosting" the pure samples, you can see exactly whats going on. :
And finally to check something else, since we have all these scans under our belt already, we covered the pure zinc metal with the pure copper foil, both of which we can measure at any time we wish, then scan them as if they were arranged as we know a US Cent to be:
First the element? "sandwich" :
Then the results of its XRF scan:
What conclusions can we draw from this failed test? "proof" and what further experiments can be added to this series?
Member Ken S sent in a wire labeled "Mystery Wire".
It is silver in color, very hard but not springy. Non magnetic. Extremely light for its volume. Many more tests to be done, but XRF was easy, and based on the elemental makeup my best guess as of today is one of the super alloys under ASTM B649-17
ASTM B649 - 17
Standard Specification for Ni-Fe-Cr-Mo-Cu-N Low-Carbon Alloys (UNS N08925, UNS N08031, UNS N08034, UNS N08354
Small mass, non magnetic even though Fe is major, low Ni content, low Cu content. Not a Nicrome, maybe an Alchrome?
Will test further, hardness, electrical resistivity, thermal conductivity,? radioactivity etc.
Thanks for trying that Charles. The idea is to eliminate the 13.9 and 17.7 keV X-Rays from the exciter source before it even strikes the target. There is a sweet spot with absorbers (aluminum) that cause this to happen, leaving the 59.5 pretty much alone. I'll dig around in my notes to report the magic thickness I came up with by experimentation.
Someone better at math than I could probably go to the HVL (Half-Value-Layer) shielding charts and find that sweet spot thickness that way. Since there are 2+ "octaves" difference between the X-Rays and Gamma Ray, each added thickness will affect the lower one more than the upper one.
Now that you have these two scans "fit together" think about making a copy of each calling one Target, the other BG (for background). Import them back into DppMCA using the OPEN command under FILE.
Next go to the toolbar icon A+B and enter the expression Target-BG so that the program combines the two together, one being negative, feeding out a new scan that is just the TARGET altered to subtract the BG,
Once you have this newly fabricated scan you can import it back into your display program. I think you will be pleased with the results.
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...>, Frank Roberts <froberts@...> Sent: Wed, 29 Jan 2020 06:42:14 -0500 (EST) Subject: [XRF] allanite-La using Am241 on Pb shield wrapped with Al foil
At George's suggestion I have been experimenting with wrapping the Am241 source with Al foil.? It seems to have improved the already very good results somewhat.
The target is an interesting specimen because it is one of the few non-radioactive rocks in my collection.? I bought it recently because it is labelled as allanite and I have many allanites in my collection but nothing from this locality.? Especially interesting is the claim that the allanites from are allanite-La instead of the usual allanite-Ce.? I set out to prove this.
I tried different number of wraps of Al foil: 0, 2, 3, and 6 layers.? Frankly, it did not seem to make much difference except perhaps reduce the noise in the lower energies some.? So once I got to 6 layers I decided to do an overnight run and that is the first attachment.? I have plotted the Am241 leakage alongside to illustrate the peaks that can be attributed to the setup.? This helps me to pick out the peaks due to the target.
I have also attached the plots of the 0, 2, 3, and 6 layers runs.? One caveat is that the 0 layers (red) was done several days before I decided to try the Al foil experiment so it was allowed to run about 3x longer than the 2-hour runs of the others based on the size of the Fe peak.? So you have to extrapolate a little, but it seems like compared to the other runs the noise baseline of the lower energies is reduced by the foil.? At some point I may remove the foil to try that run again but for now I did not want to bother.
The bottom line regarding this mineral is that it indeed appears to have allanite-La since the La peak is a little larger than the Ce peak.
Charles
Re: allanite-La using Am241 on Pb shield wrapped with Al foil
Here is the specimen.? The visible crystals are magnetite and perhaps epidote.? The allanite-La is evidently in the matrix.?
Other specimens from this locality cite data published by Del Tanago et al. (2002) as “macroscopic La-dominant allanite and REE-rich epidote crystals”.
At George's suggestion I have been experimenting with wrapping the Am241 source with Al foil.? It seems to have improved the already very good results somewhat.
The target is an interesting specimen because it is one of the few non-radioactive rocks in my collection.? I bought it recently because it is labelled as allanite and I have many allanites in my collection but nothing from this locality.? Especially interesting is the claim that the allanites from
are allanite-La instead of the usual allanite-Ce.? I set out to prove this.
I tried different number of wraps of Al foil: 0, 2, 3, and 6 layers.? Frankly, it did not seem to make much difference except perhaps reduce the noise in the lower energies some.? So once I got to 6 layers I decided to do an overnight run and that is the first attachment.? I have plotted the Am241 leakage alongside to illustrate the peaks that can be attributed to the setup.? This helps me to pick out the peaks due to the target.
I have also attached the plots of the
0, 2, 3, and 6 layers runs.? One caveat is that the 0 layers (red) was done several days before I decided to try the Al foil experiment so it was allowed to run about 3x longer than the 2-hour runs of the others based on the size of the Fe peak.? So you have to extrapolate a little, but it seems like compared to the other runs the noise baseline of the lower energies is reduced by the foil.? At some point I may remove the foil to try that run again but for now I did not want to bother.
The bottom line regarding this mineral is that it indeed appears to have allanite-La since the La peak is a little larger than the Ce peak.
Charles
allanite-La using Am241 on Pb shield wrapped with Al foil
At George's suggestion I have been experimenting with wrapping the Am241 source with Al foil.? It seems to have improved the already very good results somewhat.
The target is an interesting specimen because it is one of the few non-radioactive rocks in my collection.? I bought it recently because it is labelled as allanite and I have many allanites in my collection but nothing from this locality.? Especially interesting is the claim that the allanites from
are allanite-La instead of the usual allanite-Ce.? I set out to prove this.
I tried different number of wraps of Al foil: 0, 2, 3, and 6 layers.? Frankly, it did not seem to make much difference except perhaps reduce the noise in the lower energies some.? So once I got to 6 layers I decided to do an overnight run and that is the first attachment.? I have plotted the Am241 leakage alongside to illustrate the peaks that can be attributed to the setup.? This helps me to pick out the peaks due to the target.
I have also attached the plots of the
0, 2, 3, and 6 layers runs.? One caveat is that the 0 layers (red) was done several days before I decided to try the Al foil experiment so it was allowed to run about 3x longer than the 2-hour runs of the others based on the size of the Fe peak.? So you have to extrapolate a little, but it seems like compared to the other runs the noise baseline of the lower energies is reduced by the foil.? At some point I may remove the foil to try that run again but for now I did not want to bother.
The bottom line regarding this mineral is that it indeed appears to have allanite-La since the La peak is a little larger than the Ce peak.
It is a Si-Pin. You’ll note the 4 pt cal is very linear with deviations of 0, -0.15, 0.03 and 0.16 and the same when ?using a quadratic fit. Geo reran the cal and only shifted the
5.6 from 202 to 198 which didn’t change anything. The problem is the mineral is supposedly a very simple Fe, U phosphate. The Fe 6.4 line is located on the left shoulder of the strong peak located at 6.63. The U, although noisy, falls pretty much where it
belongs. So what is the broad peak complex at 6.63 due to? Lots of rare earths fall in this region but I wouldn’t expect that much of a response and I don’t see anything lining up.
I guess the best approach would be to re run this sample at a 4096 conversion gain and increase the beam flux and count time.
Dud
?
?Behalf Of Charles David Young Sent: Tuesday, January 28, 2020 9:16 AM To:[email protected] Subject: Re: [XRF] cyrtolite Little Patsy OT- XRF Bassetite under X-Ray tube
?
Yeah, this confuses me as well.? Is this Si-PIN?? The cal is 4 points that are not linear and very different from the 2 point cal that I have been using with Si-PIN.
Skip over to the "2020" thread for the latest Dud.
?
By the way the telephone is on here if you need.
?
Geo
?
----- Original Message -----
From: Dude <dfemer@...>
To: [email protected]
Sent: Mon, 27 Jan 2020 12:51:15 -0500 (EST)
Subject: Re: [XRF] cyrtolite Little Patsy OT- XRF Bassetite under X-Ray tube
?
Geo,
Something is wrong here. Is your E cal correct? The “Fe” is not
centered and these peaks are too broad. I assume you’re using the new sample
chamber. Where is ?this background coming from? Re-run a better rock and look
at the difference.? I think you have a bad geometry setup between the sample, detector
and the X-ray beam. Re run an old sample and compare the differences.? I’m
confused on this.
Sorry interruption, this is the Basserite scan for Charles,
plus a no-sample scan for background info- and there's a lot of background with
a full lead shield!
To my eyes-? lots of iron, very little uranium XRF when compared to iron.
Geo
?
?
?
?
?
Re: cyrtolite Little Patsy OT- XRF Bassetite under X-Ray tube
It is a Si-Pin. You’ll note the 4 pt cal is very linear with
deviations of 0, -0.15, 0.03 and 0.16 and the same when ?using a quadratic fit.
Geo reran the cal and only shifted the 5.6 from 202 to 198 which didn’t change
anything. The problem is the mineral is supposedly a very simple Fe, U phosphate.
The Fe 6.4 line is located on the left shoulder of the strong peak located at
6.63. The U, although noisy, falls pretty much where it belongs. So what is the
broad peak complex at 6.63 due to? Lots of rare earths fall in this region but I
wouldn’t expect that much of a response and I don’t see anything lining up.
I guess the best approach would be to re run this sample at a 4096
conversion gain and increase the beam flux and count time.
Dud
?
?Behalf
Of Charles
David Young Sent: Tuesday, January 28, 2020 9:16 AM To:[email protected] Subject: Re: [XRF] cyrtolite Little Patsy OT- XRF Bassetite under X-Ray
tube
?
Yeah, this confuses me as well.? Is this Si-PIN??
The cal is 4 points that are not linear and very different from the 2 point cal
that I have been using with Si-PIN.
Skip over to the "2020" thread for the latest Dud.
?
By the way the telephone is on here if you need.
?
Geo
?
----- Original Message -----
From: Dude <dfemer@...>
To: [email protected]
Sent: Mon, 27 Jan 2020 12:51:15 -0500 (EST)
Subject: Re: [XRF] cyrtolite Little Patsy OT- XRF Bassetite under X-Ray tube
?
Geo,
Something
is wrong here. Is your E cal correct? The “Fe” is not
centered and these peaks are too broad. I assume you’re using the new sample
chamber. Where is ?this background coming from? Re-run a better rock and
look
at the difference.? I think you have a bad geometry setup between the
sample, detector
and the X-ray beam. Re run an old sample and compare the differences.? I’m
confused on this.
Sorry
interruption, this is the Basserite scan for Charles,
plus a no-sample scan for background info- and there's a lot of background with
a full lead shield!
To my eyes-? lots of iron, very little uranium XRF when compared to iron.
Geo
?
?
?
?
?
Re: cyrtolite Little Patsy OT- XRF Bassetite under X-Ray tube
On Tue, Jan 28, 2020 at 11:16 AM, Charles David Young wrote:
Is this Si-PIN?? The cal is 4 points that are not linear and very different from the 2 point cal that I have been using with Si-PIN.
Yes Si-PIN, same exact unit as yours Charles. Calibration points depend on # of channels and especially gain settings. This is addressed in setup, because there is non standard. Sometimes you want 512 channels and want to examine 0-50 keV, other times you might want to examine 0-200 keV for full screen, with the same 512 channels. Or 8000 channels.
Usually I make the scan cover twice the range I'm interested in, but also at twice the channels I think might be needed. Then only display those channels that have something interesting in them. This way resolution is maintained when "zooming in", up to a point at least.
Upper range is limited by the sensor and its preamp. Max upper range for my CdTe head is 400 keV, but then the low end is chopped off. 0-200 is more practical and covers the 185 U-235 I want sometimes.
Si-PIN is of course way lower, usually I set upper end to 45keV or a little more than 60 if using 59.5 as a calibration point. Then chop off the un needed upper end with the boxes below the scan marked as RANGE- left box being lower, right box is upper. Any such temporary customization is easily cancelled on the upper row of icons by tapping the <> icon, which means "Full Range Horizontal". Non of that affects the .mca file that you store from the raw data. Two different people can display the same data in many different ways.
That's why I do so many pictures- to give a clue as to all the different settings made to show that particular scan in those terms.
Geo
Re: 2020 Portable X-Ray Tube XRF Outfit.CDY's Basstite mineral
this picture shows the calibration slope on the 50kVp .mca, what am I missing? This slope is calculated by the DppMCA program, on the same drop down menu that calibration is eneted. The box is marked "PLOT" plot?
Yeah, this confuses me as well.? Is this Si-PIN?? The cal is 4 points that are not linear and very different from the 2 point cal that I have been using with Si-PIN.
Skip over to the "2020" thread for the latest Dud.
By the way the telephone is on here if you need.
Geo
----- Original Message ----- From: Dude <dfemer@...> To: [email protected] Sent: Mon, 27 Jan 2020 12:51:15 -0500 (EST) Subject: Re: [XRF] cyrtolite Little Patsy OT- XRF Bassetite under X-Ray tube
Geo,
Something is wrong here. Is your E cal correct? The “Fe” is not centered and these peaks are too broad. I assume you’re using the new sample chamber. Where is ?this background coming from? Re-run a better rock and look at the difference.? I think you have a bad geometry setup between the sample, detector and the X-ray beam. Re run an old sample and compare the differences.? I’m confused on this.
Sorry interruption, this is the Basserite scan for Charles, plus a no-sample scan for background info- and there's a lot of background with a full lead shield!
To my eyes-? lots of iron, very little uranium XRF when compared to iron.
Hi Ken, welcome here and thanks for the great question.
I'll post some pictures soon, and I'm sure other members will do the same, but right now, use this link to print a copy of the XRF Periodic Table of the Elements. We look at atoms from a slightly different perspective. The one I use most is?
I'm a newcomer to the group (thanks Geo for granting me membership), and am amazed at the technical knowledge of the members.? I've certainly got a lot to learn about XRF. I was remotely associated with some XRF analyses in a chemistry group where I used to work, so I'm familiar (I think) with the concepts of how the process works.? When a substance under question is exposed to X-rays or gamma photons of a greater energy, the substance emits characteristic X-rays of a specific energy providing information related to the elemental composition of the substance.
However, my question is this:? Can XRF provide information about the PHYSICAL composition of the substance?? I know that an entirely different field of X-ray crystallography exists, but my question is more related to 'entry-level' XRF.? For example, if one analyzed a slug of brass alloy (a homogeneous mixture of copper and zinc), the spectrum obtained would indicate the presence of Cu and Zn in proportions related to the elemental composition of the brass alloy.? However, a modern USA 1-cent penny coin is a slug of zinc clad in a copper jacket.? Although not a true alloy, a penny also has both copper and zinc.? Would an XRF analysis of a penny coil yield an XRF spectrum that would differ from that of a comparable-mix brass alloy?? Can one use the XRF spectrum of a penny to elucidate the fact that it is a "sandwich" of copper and zinc, as opposed to a true homogeneous mix of Cu and Zn in a brass alloy?? My limited knowledge of the physics behind? XRF analysis says "No", but am I missing anything?
Thanks so much for indulging my questions.
Respectfully,
Ken Sejkora,?WB?OCV East Falmouth, MA USA?
Re: 2020 Portable X-Ray Tube XRF Outfit.CDY's Basstite mineral
----- Original Message ----- From: Dude <dfemer@...> To: [email protected] Sent: Mon, 27 Jan 2020 12:51:15 -0500 (EST) Subject: Re: [XRF] cyrtolite Little Patsy OT- XRF Bassetite under X-Ray tube
Geo,
Something is wrong here. Is your E cal correct? The “Fe” is not centered and these peaks are too broad. I assume you’re using the new sample chamber. Where is ?this background coming from? Re-run a better rock and look at the difference.? I think you have a bad geometry setup between the sample, detector and the X-ray beam. Re run an old sample and compare the differences.? I’m confused on this.
dud
?
From:[email protected] [mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Monday, January 27, 2020 8:25 AM To:[email protected] Subject: Re: [XRF] cyrtolite Little Patsy OT- XRF Bassetite under X-Ray tube
?
Sorry interruption, this is the Basserite scan for Charles, plus a no-sample scan for background info- and there's a lot of background with a full lead shield!
To my eyes-? lots of iron, very little uranium XRF when compared to iron.
Geo
Re: 2020 Portable X-Ray Tube XRF Outfit.CDY's Basstite mineral
Here we go Charles, your Bassetite sample under XRF via X-Ray tube, shown here in LINEAR representation to give an idea of proportion, +/- sensor efficiency and beam peak energy.
Before anyone runs out and installs a LIXI or any other source like it, keep in mind the safety equipment,? measures and training that must accompany that investment.?
Below is a picture rare picture showing just the tip of the iceberg- an L Block, of which I own and use a dozen, along with? lead glass plates and bricks up to 2" etc. etc.plus a full sized rolling lead "wall" shield, with lead glass window, not to mention the lead garments, and especially the low energy ion-chamber type X-Ray test equipment. Staying out of the beam is important, but the insidious danger are scattered rays that appear where they would not likely be expected. The lower the energy either being generated, or that is left once a beam is deflected, the more it is absorbed by biologicals.
Specialized beam detectors as used in the counting room.
Something is wrong here. Is your E cal correct? The “Fe” is not
centered and these peaks are too broad. I assume you’re using the new sample
chamber. Where is ?this background coming from? Re-run a better rock and look
at the difference.? I think you have a bad geometry setup between the sample, detector
and the X-ray beam. Re run an old sample and compare the differences.? I’m
confused on this.
From:[email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Monday, January 27, 2020 8:25 AM To:[email protected] Subject: Re: [XRF] cyrtolite Little Patsy OT- XRF Bassetite under X-Ray
tube
?
Sorry interruption, this is the Basserite scan for Charles,
plus a no-sample scan for background info- and there's a lot of background with
a full lead shield!
To my eyes-? lots of iron, very little uranium XRF when compared to iron.
