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.
?
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 If a piece of information is incorrect, a link outdated, or the presentation choppy or unclear, the user can just click "Edit Page" at the bottom and then fix the mistake.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?]
Red Trinitite. Some have said the red color in some Trinitite is there because it was stored in metal drums which rusted, then transferred the rust to the Trinitite.
Others claim it is copper, from the multitude of heavy copper wires carrying signals to and from the shot tower.
Red Trinitite is very interesting simply? because it is different from the far more common green variety.
----- Original Message ----- From: Dude <dfemer@...> To: [email protected] Sent: Sat, 08 Feb 2020 00:36:20 -0500 (EST) Subject: Re: [XRF] The case of the missing elements
I use a Rock crusher for big rock samples.? Most are just done in using a cloth covered hammer and then a ceramic mortar and pestle then sieving the powder down to a uniform and appropriate size.? Yeah, I don¡¯t crush my nice specimens but I do when I have a bulk prospecting ?sample.
Using a rock saw to get a flat surface cut to look at the homogeneity of the rock is useful as well then selecting the target area to shoot
The biggest issue I see with trying to determine what a mineral is, is using the elemental composition to justify what Mindat says should be in it.? If it¡¯s a single crystal that¡¯s ok, but to shoot a whole rock and make a definitive statement that its¡± leaverite¡± is wrong as you have no idea what is fluorescing, a xtal? the matrix? or the host rock¡¯s body - anyone of which will introduce its own elements.?
Powdering a specimen is a common and practical way of getting a uniform xrf, but like you mentioned Dud, us collectors do cringe at that especially if it is unusual, expensive, and/or hard to replace. Microprobe analysis of specimens is maybe a little worse, where a chunk has to be taken out of the mineral.
?
How would you prepare a sample like that? Taking a piece off with a Dremel or even a cheese grater might introduce contamination. Do you know how labs do it, and can we do this in the home lab? I have some samples I can use so I am willing to give it a try.
Good points here Geo. However we¡¯re all doing this all wrong and comparing apples to oranges.?
The excitation sources have widely different energies and source strength and exposure is from within or on the surface.? Worse yet we have no idea of the elemental distribution in the matrix which is going to determine what gets excited and what gets absorbed. ?What is the gamma activity of the Cerite? What¡¯s the mass. Is this a big boy or a chip?
The excitation energy from the Th is going to be very high while the Am is lower in energy and has the Np x-rays which are closer and stronger to excite the absorption edges of both the Fe and Y.? But the biggest problem is just what are you exciting and where is it ¨C on the surface, deep inside just a small xtal?
To properly compare these measurements the rock should be pulverized down to 200 u or so (Charles just cringed) ?mixed and homogenized and put into a XRF cup with a mylar cover and then measured.? It makes for a homogenous mixture removing the ambiguity of what the matrix effects are.
I think Geo is right in the density- thickness problem and the different source ?strengths.
Charles, I have an external ?higher activity natural ?source that I think you might like to try, give me a call
Hi Charles, cool observation. If I may guess at it:
?
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
?
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
?
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
?
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
?
So your method might show up something that an external exciter misses.
?
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
?
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
?
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
?
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
?
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though it looked quite uniform.
?
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
?
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
How would you prepare a sample like that? Taking a piece off with a Dremel or even a cheese grater might introduce contamination. Do you know how labs do it, and can we do this in the home lab? I have some samples I can use so I am willing to give it a try.
Steve"
Take that a step further Steve, and compress the powder into a standard pellet, and you have the perfect sample for XRD, or X-Ray Diffraction. Using that method the phase of the mineral can be determined as well as the elements.
Crushing- I use a cast iron mortar and pestle, available in different sizes from any mining outfitter.
----- Original Message ----- From: WILLIAM S Dubyk <sdubyk@...> To: [email protected] Sent: Sat, 08 Feb 2020 00:01:50 -0500 (EST) Subject: Re: [XRF] The case of the missing elements
Powdering a specimen is a common and practical way of getting a uniform xrf, but like you mentioned Dud, us collectors do cringe at that especially if it is unusual, expensive, and/or hard to replace. Microprobe analysis of specimens is maybe a little worse, where a chunk has to be taken out of the mineral.
How would you prepare a sample like that? Taking a piece off with a Dremel or even a cheese grater might introduce contamination. Do you know how labs do it, and can we do this in the home lab? I have some samples I can use so I am willing to give it a try.
Good points here Geo. However we¡¯re all doing this all wrong and comparing apples to oranges.?
The excitation sources have widely different energies and source strength and exposure is from within or on the surface.? Worse yet we have no idea of the elemental distribution in the matrix which is going to determine what gets excited and what gets absorbed. ?What is the gamma activity of the Cerite? What¡¯s the mass. Is this a big boy or a chip?
The excitation energy from the Th is going to be very high while the Am is lower in energy and has the Np x-rays which are closer and stronger to excite the absorption edges of both the Fe and Y.? But the biggest problem is just what are you exciting and where is it ¨C on the surface, deep inside just a small xtal?
To properly compare these measurements the rock should be pulverized down to 200 u or so (Charles just cringed) ?mixed and homogenized and put into a XRF cup with a mylar cover and then measured.? It makes for a homogenous mixture removing the ambiguity of what the matrix effects are.
I think Geo is right in the density- thickness problem and the different source ?strengths.
Charles, I have an external ?higher activity natural ?source that I think you might like to try, give me a call
Hi Charles, cool observation. If I may guess at it:
?
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
?
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
?
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
?
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
?
So your method might show up something that an external exciter misses.
?
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
?
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
?
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
?
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
?
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though it looked quite uniform.
?
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
?
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
Dud, of course you are correct. And that technology is not out of reach of the serious amateur. However, here, just like amateur radio, we are all amateurs, and will evolve to different levels of "perfection", as is comfortable and affordable, step by step, always learning along the way.
On the other hand, we must stress that this group is not for the beginner Gamma Spec novice. There are plenty of those types of groups going around where the question "what is Gamma Spectrum Analysis" is better served.
The reason I started this group was to allow those of us with a working knowledge of Gamma Spec with a tilt towards XRF and other Non-Destructive methods of material analysis can ask the not so obvious questions. I'm very pleased where we are now as a group and see nothing but good things to come from future members. Let's all remember what we write is not just being read by our members but by anyone who looks us up on the open internet. In other words anyone can read our messages if they are members or not.
To those out there reading this message that are not members, I say think about joining us if you already have a working Gamma Spec and or XRF unit.
----- Original Message ----- From: Dude <dfemer@...> To: [email protected] Sent: Fri, 07 Feb 2020 23:37:40 -0500 (EST) Subject: Re: [XRF] The case of the missing elements
Good points here Geo. However we¡¯re all doing this all wrong and comparing apples to oranges.?
The excitation sources have widely different energies and source strength and exposure is from within or on the surface.? Worse yet we have no idea of the elemental distribution in the matrix which is going to determine what gets excited and what gets absorbed. ?What is the gamma activity of the Cerite? What¡¯s the mass. Is this a big boy or a chip?
The excitation energy from the Th is going to be very high while the Am is lower in energy and has the Np x-rays which are closer and stronger to excite the absorption edges of both the Fe and Y.? But the biggest problem is just what are you exciting and where is it ¨C on the surface, deep inside just a small xtal?
To properly compare these measurements the rock should be pulverized down to 200 u or so (Charles just cringed) ?mixed and homogenized and put into a XRF cup with a mylar cover and then measured.? It makes for a homogenous mixture removing the ambiguity of what the matrix effects are.
I think Geo is right in the density- thickness problem and the different source ?strengths.
Charles, I have an external ?higher activity natural ?source that I think you might like to try, give me a call
Hi Charles, cool observation. If I may guess at it:
?
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
?
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
?
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
?
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
?
So your method might show up something that an external exciter misses.
?
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
?
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
?
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
?
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
?
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though it looked quite uniform.
?
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
?
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
I use a Rock crusher for big rock samples.? Most are just done in using a cloth covered hammer and then a ceramic mortar and pestle then sieving the powder down to a uniform and
appropriate size.? Yeah, I don¡¯t crush my nice specimens but I do when I have a bulk prospecting ?sample.
Using a rock saw to get a flat surface cut to look at the homogeneity of the rock is useful as well then selecting the target area to shoot
The biggest issue I see with trying to determine what a mineral is, is using the elemental composition to justify what Mindat says should be in it.? If it¡¯s a single crystal that¡¯s
ok, but to shoot a whole rock and make a definitive statement that its¡± leaverite¡± is wrong as you have no idea what is fluorescing, a xtal? the matrix? or the host rock¡¯s body - anyone of which will introduce its own elements.?
Powdering a specimen is a common and practical way of getting a uniform xrf, but like you mentioned Dud, us collectors do cringe at that especially if it is unusual, expensive, and/or hard to replace.
Microprobe analysis of specimens is maybe a little worse, where a chunk has to be taken out of the mineral.
?
How would you prepare a sample like that? Taking a piece off with a Dremel or even a cheese grater might introduce contamination. Do you know how labs do it, and can we do this in the home lab? I
have some samples I can use so I am willing to give it a try.
Good points here Geo. However we¡¯re all doing this all wrong and comparing apples to oranges.?
The excitation sources have widely different energies and source strength and exposure is from within or on the surface.? Worse yet we have no idea of the elemental distribution
in the matrix which is going to determine what gets excited and what gets absorbed. ?What is the gamma activity of the Cerite? What¡¯s the mass. Is this a big boy or a chip?
The excitation energy from the Th is going to be very high while the Am is lower in energy and has the Np x-rays which are closer and stronger to excite the absorption edges of
both the Fe and Y.? But the biggest problem is just what are you exciting and where is it ¨C on the surface, deep inside just a small xtal?
To properly compare these measurements the rock should be pulverized down to 200 u or so (Charles just cringed) ?mixed and homogenized and put into a XRF cup with a mylar cover
and then measured.? It makes for a homogenous mixture removing the ambiguity of what the matrix effects are.
I think Geo is right in the density- thickness problem and the different source ?strengths.
Charles, I have an external ?higher activity natural ?source that I think you might like to try, give me a call
Hi Charles, cool observation. If I may guess at it:
?
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
?
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
?
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
?
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
?
So your method might show up something that an external exciter misses.
?
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better
it.....
?
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as
far as the elements at the surface and a little further inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
?
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
?
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite
are from Np or U atoms, or both.
?
Geo
?
?
----- Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected], Mike Loughlin <loughlin3@...>
Sent: Fri, 07 Feb 2020 17:12:15 -0500 (EST)
Subject: [XRF] The case of the missing elements
?
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
?
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was
careful to keep the same spot on the rock even though it looked quite uniform.
?
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
?
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly
compared to the internal radiation.? It is kind of a pain to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
I use a Rock crusher for big rock samples.? Most are just
done in using a cloth covered hammer and then a ceramic mortar and pestle then sieving
the powder down to a uniform and appropriate size.? Yeah, I don¡¯t
crush my nice specimens but I do when I have a bulk prospecting ?sample.
Using a rock saw to get a flat surface cut to look at the homogeneity
of the rock is useful as well then selecting the target area to shoot
The biggest issue I see with trying to determine what a mineral is,
is using the elemental composition to justify what Mindat says should be in
it.? If it¡¯s a single crystal that¡¯s ok, but to shoot a whole
rock and make a definitive statement that its¡± leaverite¡± is wrong
as you have no idea what is fluorescing, a xtal? the matrix? or the host rock¡¯s
body - anyone of which will introduce its own elements.?
Powdering
a specimen is a common and practical way of getting a uniform xrf, but like you
mentioned Dud, us collectors do cringe at that especially if it is unusual,
expensive, and/or hard to replace. Microprobe analysis of specimens is maybe a
little worse, where a chunk has to be taken out of the mineral.
?
How
would you prepare a sample like that? Taking a piece off with a Dremel or even
a cheese grater might introduce contamination. Do you know how labs do it, and
can we do this in the home lab? I have some samples I can use so I am willing
to give it a try.
Good points here Geo. However we¡¯re all doing this all wrong
and comparing apples to oranges.?
The excitation sources have widely different energies and source
strength and exposure is from within or on the surface.? Worse yet we have
no idea of the elemental distribution in the matrix which is going to determine
what gets excited and what gets absorbed. ?What is the gamma activity of
the Cerite? What¡¯s the mass. Is this a big boy or a chip?
The excitation energy from the Th is going to be very high while
the Am is lower in energy and has the Np x-rays which are closer and stronger
to excite the absorption edges of both the Fe and Y.? But the biggest
problem is just what are you exciting and where is it ¨C on the surface,
deep inside just a small xtal?
To properly compare these measurements the rock should be pulverized
down to 200 u or so (Charles just cringed) ?mixed and homogenized and put
into a XRF cup with a mylar cover and then measured.? It makes for a
homogenous mixture removing the ambiguity of what the matrix effects are.
I think Geo is right in the density- thickness problem and the
different source ?strengths.
Charles, I have an external ?higher activity natural
?source that I think you might like to try, give me a call
Hi
Charles, cool observation. If I may guess at it:
?
We
know from experience that an atom will make XRF if excited by energy from
alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways
too.
?
So
if you rely on internal energy to do this, it will do so in response to the
available radiation from the rock. Some have LOTS, some have very little, some
almost none.
?
One
advantage to that way is all the atoms, even those deep within a big rock are
being excited. If those XRF rays can get out depends only on the energy of the
ray and the overburden.
?
Rays
above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This
goes for adding external energy or gathering internally generated XRF.
?
So
your method might show up something that an external exciter misses.
?
But
a good exciter will work on a rock that has no discernable radioactivity, the
thing is how radioactive is the rock and how radioactive is does the external
exciter have to be to equal or better it.....
?
The
pro units have a need for speed so they have X-Ray tubes, blasting the sample
with as much as the law allows. We don't actually have a need for speed so we
can use tiny little exciters, but as far as the elements at the surface and a
little further inside are concerned, it is much more "exciting" than
the stuff coming from deep inside and spread over the entire surface of the
rock.
?
In
other words it may be small, but it is concentrated where it counts, we
substitute long run times to get the results we need.
?
Say
on another note, do you have enough Trinitite to do some Gamma Spec runs on it
with your Si-PIN? You could precisely calibrate the detector with Am, the see
if the X-Rays coming from Trinitite are from Np or U atoms, or both.
?
Geo
?
?
-----
Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected], Mike Loughlin <loughlin3@...>
Sent: Fri, 07 Feb 2020 17:12:15 -0500 (EST)
Subject: [XRF] The case of the missing elements
?
I
recently picked up a specimen of melanocerite-Ce at the mineral show and did a
scan without Am241 by depending on the internal radiation.? I was not
surprised to see Th La Ce and Nd in the blue plot.
?
Then
I wanted to see if I got the same results using Am241 as an additional
exciter.? So I carefully moved the specimen just far enough from the
detector to allow me to slide in the Am241 jig.? I was careful to keep the
same spot on the rock even though it looked quite uniform.
?
Curiously
I am now getting additional strong Fe and Y peaks in the red plot.? What
could account for this?? I am not surprised that the La Ce Nd are lit up
as they are.
?
I
have also attached both .mca files in case one wishes to analyze them.?
However, I am not really asking for that.? I would just like to understand
why the Am241 lights up the Fe and Y so strongly compared to the internal
radiation.? It is kind of a pain to weed through the Am241 background
peaks but it appears that I may not get a complete picture with the internal
radiation alone.
Powdering a specimen is a common and practical way of getting a uniform xrf, but like you mentioned Dud, us collectors do cringe at that especially if it is unusual, expensive, and/or hard to replace. Microprobe analysis of specimens is maybe a little
worse, where a chunk has to be taken out of the mineral.
How would you prepare a sample like that? Taking a piece off with a Dremel or even a cheese grater might introduce contamination. Do you know how labs do it, and can we do this in the home lab? I have some samples I can use so I am willing to give it
a try.
Good points here Geo. However we¡¯re all doing this all wrong and comparing apples to oranges.?
The excitation sources have widely different energies and source strength and exposure is from within or on the surface.? Worse yet we have no idea of the elemental distribution
in the matrix which is going to determine what gets excited and what gets absorbed. ?What is the gamma activity of the Cerite? What¡¯s the mass. Is this a big boy or a chip?
The excitation energy from the Th is going to be very high while the Am is lower in energy and has the Np x-rays which are closer and stronger to excite the absorption edges of
both the Fe and Y.? But the biggest problem is just what are you exciting and where is it ¨C on the surface, deep inside just a small xtal?
To properly compare these measurements the rock should be pulverized down to 200 u or so (Charles just cringed) ?mixed and homogenized and put into a XRF cup with a mylar cover
and then measured.? It makes for a homogenous mixture removing the ambiguity of what the matrix effects are.
I think Geo is right in the density- thickness problem and the different source ?strengths.
Charles, I have an external ?higher activity natural ?source that I think you might like to try, give me a call
Hi Charles, cool observation. If I may guess at it:
?
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
?
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
?
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
?
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
?
So your method might show up something that an external exciter misses.
?
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better
it.....
?
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as
far as the elements at the surface and a little further inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
?
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
?
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite
are from Np or U atoms, or both.
?
Geo
?
?
----- Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected], Mike Loughlin <loughlin3@...>
Sent: Fri, 07 Feb 2020 17:12:15 -0500 (EST)
Subject: [XRF] The case of the missing elements
?
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
?
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was
careful to keep the same spot on the rock even though it looked quite uniform.
?
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
?
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly
compared to the internal radiation.? It is kind of a pain to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
Good points here Geo. However we¡¯re all doing this all wrong and comparing
apples to oranges.?
The excitation sources have widely different energies and source
strength and exposure is from within or on the surface.? Worse yet we have no
idea of the elemental distribution in the matrix which is going to determine
what gets excited and what gets absorbed. ?What is the gamma activity of the
Cerite? What¡¯s the mass. Is this a big boy or a chip?
The excitation energy from the Th is going to be very high while the
Am is lower in energy and has the Np x-rays which are closer and stronger to
excite the absorption edges of both the Fe and Y.? But the biggest problem is
just what are you exciting and where is it ¨C on the surface, deep inside just a
small xtal?
To properly compare these measurements the rock should be pulverized
down to 200 u or so (Charles just cringed) ?mixed and homogenized and put into
a XRF cup with a mylar cover and then measured.? It makes for a homogenous mixture
removing the ambiguity of what the matrix effects are.
I think Geo is right in the density- thickness problem and the different
source ?strengths.
Charles, I have an external ?higher activity natural ?source that
I think you might like to try, give me a call
Hi
Charles, cool observation. If I may guess at it:
?
We
know from experience that an atom will make XRF if excited by energy from
alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways
too.
?
So
if you rely on internal energy to do this, it will do so in response to the
available radiation from the rock. Some have LOTS, some have very little, some
almost none.
?
One
advantage to that way is all the atoms, even those deep within a big rock are
being excited. If those XRF rays can get out depends only on the energy of the
ray and the overburden.
?
Rays
above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This
goes for adding external energy or gathering internally generated XRF.
?
So
your method might show up something that an external exciter misses.
?
But
a good exciter will work on a rock that has no discernable radioactivity, the
thing is how radioactive is the rock and how radioactive is does the external
exciter have to be to equal or better it.....
?
The
pro units have a need for speed so they have X-Ray tubes, blasting the sample
with as much as the law allows. We don't actually have a need for speed so we
can use tiny little exciters, but as far as the elements at the surface and a
little further inside are concerned, it is much more "exciting" than
the stuff coming from deep inside and spread over the entire surface of the
rock.
?
In
other words it may be small, but it is concentrated where it counts, we
substitute long run times to get the results we need.
?
Say
on another note, do you have enough Trinitite to do some Gamma Spec runs on it
with your Si-PIN? You could precisely calibrate the detector with Am, the see
if the X-Rays coming from Trinitite are from Np or U atoms, or both.
?
Geo
?
?
-----
Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: [email protected], Mike Loughlin <loughlin3@...>
Sent: Fri, 07 Feb 2020 17:12:15 -0500 (EST)
Subject: [XRF] The case of the missing elements
?
I
recently picked up a specimen of melanocerite-Ce at the mineral show and did a
scan without Am241 by depending on the internal radiation.? I was not
surprised to see Th La Ce and Nd in the blue plot.
?
Then
I wanted to see if I got the same results using Am241 as an additional exciter.?
So I carefully moved the specimen just far enough from the detector to allow me
to slide in the Am241 jig.? I was careful to keep the same spot on the
rock even though it looked quite uniform.
?
Curiously
I am now getting additional strong Fe and Y peaks in the red plot.? What
could account for this?? I am not surprised that the La Ce Nd are lit up
as they are.
?
I
have also attached both .mca files in case one wishes to analyze them.?
However, I am not really asking for that.? I would just like to understand
why the Am241 lights up the Fe and Y so strongly compared to the internal
radiation.? It is kind of a pain to weed through the Am241 background
peaks but it appears that I may not get a complete picture with the internal
radiation alone.
For the reasons you mention, I use Si-PIN for everyday stuff. The SDD was acquired for its high count rate capability, and is intended for the cabinet XRF machine in the basement. It's a Hitachi Vortex-EX, has its own power supply, just a BNC cable over to the Amptek PX4 MCA, then USB to the notebook computer.
Great, yeah I hang there too when we drive through. Last trip was the day they installed the new mass spectrometer, I was really eyeing the old one for possibilities, but sanity prevailed.
Now I can drop YOUR name as the person responsible for the signs concerning watching and reporting suspicious persons hanging around, posted next to the elevator doors.
----- Original Message ----- From: WILLIAM S Dubyk <sdubyk@...> To: [email protected] Sent: Fri, 07 Feb 2020 22:29:13 -0500 (EST) Subject: Re: [XRF] The case of the missing elements
Yes it is in Northrup Hall, no I just hang out there, know some folks and make a nuisance of myself. I saw Jim last October at the mineral show, he has a booth there, we yacked it up for a while. I am sure he will be there at the spring show in March. He's a good guy.
Subject: Re: [XRF] The case of the missing elements
No it's all university level microprobe stuff from the local Institute of Meteoritics at UNM, nothing I can afford or have room for or even know how to use. The concept of using both the internal and external sources of x-rays for an analysis is very
interesting, but it's going to take some work to figure out what it all means. I like the idea of using both for an analysis though, I don't think it has ever really been pursued. Charles has been the champion of this in the group.
That's a great representation of the inclusions Steve.?
Is the X-Ray mapping done with electrons on an SEM or some other? Looks really cool. Also the photomicrographs. Do you have your own inverted microscope?
One thing I use the X-Ray viewer for it to trace veins inside rocks so I know where to look with other devices. Nothing fancy, pretty basic stuff.
Subject: Re: [XRF] The case of the missing elements
Attached is an example of how radionuclides can be distributed within a mineral specimen, showing the variability of the depth of these included sources. There is an excellent picture of my knee on one of the slides.
Hi Charles, cool observation. If I may guess at it:
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
So your method might show up something that an external exciter misses.
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further
inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though
it looked quite uniform.
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain
to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
----- Original Message ----- From: Dude <dfemer@...> To: [email protected] Sent: Fri, 07 Feb 2020 22:21:47 -0500 (EST) Subject: Re: [XRF] Mystery wire
Ken,
Yes, the insulation was left on the wire.? The low energy response is mostly noise although one could possibly conjure up a Cl peak if one was reckless enough in the interp.? The high percentage is the due to ?the fact that the efficiency in this energy range is so low that little things blow up quickly unless you have a lot of material, count time and run a vacuum or He fill.
The odd guy is the Cd. The 316 SS has V, Ti and Nb whereas this wire doesn¡¯t but has Cd and Zn
Geo, did you run yours with or without the insulation?.
Thanks for the very detailed analysis of the mystery wire.? I see in the description that you call it ¡®insulated wire¡¯.? Was the insulation still on the wire when you ran the analysis, or had the insulation been removed?? I don¡¯t know for certain, but suspect the insulation might possibly be Teflon, or something of similar nature.? If the analysis was performed with the insulation still on the wire, could that account for some of the low-energy (LE) response, potentially from the Carbon, Chlorine, and Fluorine, etc. if the insulation was indeed Teflon?
?
I¡¯ll have to pull out Geo¡¯s results and see how they compare, although I don¡¯t recall that he quantified percentages of each of the metals in the mix. Again, many thanks for your analysis of the wire.?
?
Have a great weekend.
?
73s? --? Ken
?
?
From: Dude Sent: Friday, February 7, 2020 04:05 PM To: [email protected] Subject: [XRF] Mystery wire
?
Ken,
Attached are the results of your Mystery Wire.
The data were taken with an Olympus DP4050 pXRF. As I don¡¯t have an ALLOY calibration for this gun I used the Mining Mode to get the percentage of elements present
The set up used a 50kV 11 uA x-ray beam with a live time of 30 secs obtaining account rate of 9505 cps from the SDD detector.
?
Mn was identified but it has an interference from Cr and Fe, probably there but not confirmed
Charles, I would suggest starting with some lower to intermediate rad minerals with simple formulas, like columbite, monazite, and even zircon. Run both internal and external tests on each. Zircon would be good too, I'm thinking maybe Mt. Malosa which
has high Th contents in the cores, and Wichita Mountains zircon which have Th in the outer areas. That might be pretty interesting. I got those if you want to check them out.
Dud pointed out that I had a wrong filename so I have attached the files again with the corrections.
I like George's explanation for why Fe and Y are not showing up with internal radiation.? These relatively low energies can't escape from the rock.? However, the Am241 excites the surface of the rock and allows these energies to reach the detector.? Very
elegant!
That's a great representation of the inclusions Steve.?
Is the X-Ray mapping done with electrons on an SEM or some other? Looks really cool. Also the photomicrographs. Do you have your own inverted microscope?
One thing I use the X-Ray viewer for it to trace veins inside rocks so I know where to look with other devices. Nothing fancy, pretty basic stuff.
Geo
----- Original Message -----
From: WILLIAM S Dubyk <sdubyk@...>
To: [email protected]
Sent: Fri, 07 Feb 2020 21:15:05 -0500 (EST)
Subject: Re: [XRF] The case of the missing elements
Attached is an example of how radionuclides can be distributed within a mineral specimen, showing the variability of the depth of these included sources. There is an excellent picture of my knee on one of the slides.
Hi Charles, cool observation. If I may guess at it:
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
So your method might show up something that an external exciter misses.
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further
inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though
it looked quite uniform.
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain
to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
Yes it is in Northrup Hall, no I just hang out there, know some folks and make a nuisance of myself. I saw Jim last October at the mineral show, he has a booth there, we yacked it up for a while. I am sure he will be there at the spring show in March. He's
a good guy.
Cool on the U of NM, is it in the same building as the cyclotron and meteor museum?
Do you work there or is it a club? Do you see Jim Hill anymore? Haven't heard from him since our last trip to Trinity.
Geo
----- Original Message -----
From: WILLIAM S Dubyk <sdubyk@...>
To: [email protected]
Sent: Fri, 07 Feb 2020 21:54:12 -0500 (EST)
Subject: Re: [XRF] The case of the missing elements
No it's all university level microprobe stuff from the local Institute of Meteoritics at UNM, nothing I can afford or have room for or even know how to use. The concept of using both the internal and external sources of x-rays for an analysis is very
interesting, but it's going to take some work to figure out what it all means. I like the idea of using both for an analysis though, I don't think it has ever really been pursued. Charles has been the champion of this in the group.
That's a great representation of the inclusions Steve.?
Is the X-Ray mapping done with electrons on an SEM or some other? Looks really cool. Also the photomicrographs. Do you have your own inverted microscope?
One thing I use the X-Ray viewer for it to trace veins inside rocks so I know where to look with other devices. Nothing fancy, pretty basic stuff.
Subject: Re: [XRF] The case of the missing elements
Attached is an example of how radionuclides can be distributed within a mineral specimen, showing the variability of the depth of these included sources. There is an excellent picture of my knee on one of the slides.
Hi Charles, cool observation. If I may guess at it:
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
So your method might show up something that an external exciter misses.
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further
inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though
it looked quite uniform.
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain
to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
Yes, the insulation was left on
the wire.? The low energy response is mostly noise although one could possibly conjure
up a Cl peak if one was reckless enough in the interp.? The high percentage is
the due to ?the fact that the efficiency in this energy range is so low that little
things blow up quickly unless you have a lot of material, count time and run a vacuum
or He fill.
The odd guy is the Cd. The 316 SS
has V, Ti and Nb whereas this wire doesn¡¯t but has Cd and Zn
Geo, did you run yours with or
without the insulation?.
Thanks for the very detailed analysis of the mystery
wire.? I see in the description that you call it ¡®insulated wire¡¯.?
Was the insulation still on the wire when you ran the analysis, or had the
insulation been removed?? I don¡¯t know for certain, but suspect the
insulation might possibly be Teflon, or something of similar nature.? If
the analysis was performed with the insulation still on the wire, could that
account for some of the low-energy (LE) response, potentially from the Carbon,
Chlorine, and Fluorine, etc. if the insulation was indeed Teflon?
?
I¡¯ll have to pull out Geo¡¯s results and see how they
compare, although I don¡¯t recall that he quantified percentages of each of the
metals in the mix. Again, many thanks for your analysis of the wire.?
?
Have a great weekend.
?
73s? --? Ken
?
?
From: Dude Sent: Friday, February 7, 2020 04:05 PM To: [email protected] Subject: [XRF] Mystery wire
?
Ken,
Attached are the
results of your Mystery Wire.
The data were
taken with an Olympus DP4050 pXRF. As I don¡¯t have an ALLOY calibration for
this gun I used the Mining Mode to get the percentage of elements present
The set up used a
50kV 11 uA x-ray beam with a live time of 30 secs obtaining account rate of
9505 cps from the SDD detector.
?
Mn was identified
but it has an interference from Cr and Fe, probably there but not confirmed
Dud pointed out that I had a wrong filename so I have attached the files again with the corrections.
I like George's explanation for why Fe and Y are not showing up with internal radiation.? These relatively low energies can't escape from the rock.? However, the Am241 excites the surface of the rock and allows these energies to reach the detector.? Very elegant!
That's a great representation of the inclusions Steve.?
Is the X-Ray mapping done with electrons on an SEM or some other? Looks really cool. Also the photomicrographs. Do you have your own inverted microscope?
One thing I use the X-Ray viewer for it to trace veins inside rocks so I know where to look with other devices. Nothing fancy, pretty basic stuff.
Geo
----- Original Message ----- From: WILLIAM S Dubyk <sdubyk@...> To: [email protected] Sent: Fri, 07 Feb 2020 21:15:05 -0500 (EST) Subject: Re: [XRF] The case of the missing elements
Attached is an example of how radionuclides can be distributed within a mineral specimen, showing the variability of the depth of these included sources. There is an excellent picture of my knee on one of the slides.
Hi Charles, cool observation. If I may guess at it:
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
So your method might show up something that an external exciter misses.
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though it looked quite uniform.
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
----- Original Message ----- From: WILLIAM S Dubyk <sdubyk@...> To: [email protected] Sent: Fri, 07 Feb 2020 21:54:12 -0500 (EST) Subject: Re: [XRF] The case of the missing elements
No it's all university level microprobe stuff from the local Institute of Meteoritics at UNM, nothing I can afford or have room for or even know how to use. The concept of using both the internal and external sources of x-rays for an analysis is very interesting, but it's going to take some work to figure out what it all means. I like the idea of using both for an analysis though, I don't think it has ever really been pursued. Charles has been the champion of this in the group.
That's a great representation of the inclusions Steve.?
Is the X-Ray mapping done with electrons on an SEM or some other? Looks really cool. Also the photomicrographs. Do you have your own inverted microscope?
One thing I use the X-Ray viewer for it to trace veins inside rocks so I know where to look with other devices. Nothing fancy, pretty basic stuff.
Subject: Re: [XRF] The case of the missing elements
Attached is an example of how radionuclides can be distributed within a mineral specimen, showing the variability of the depth of these included sources. There is an excellent picture of my knee on one of the slides.
Hi Charles, cool observation. If I may guess at it:
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
So your method might show up something that an external exciter misses.
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further
inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though
it looked quite uniform.
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain
to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
No it's all university level microprobe stuff from the local Institute of Meteoritics at UNM, nothing I can afford or have room for or even know how to use. The concept of using both the internal and external sources of x-rays for an analysis is very
interesting, but it's going to take some work to figure out what it all means. I like the idea of using both for an analysis though, I don't think it has ever really been pursued. Charles has been the champion of this in the group.
That's a great representation of the inclusions Steve.?
Is the X-Ray mapping done with electrons on an SEM or some other? Looks really cool. Also the photomicrographs. Do you have your own inverted microscope?
One thing I use the X-Ray viewer for it to trace veins inside rocks so I know where to look with other devices. Nothing fancy, pretty basic stuff.
Geo
----- Original Message -----
From: WILLIAM S Dubyk <sdubyk@...>
To: [email protected]
Sent: Fri, 07 Feb 2020 21:15:05 -0500 (EST)
Subject: Re: [XRF] The case of the missing elements
Attached is an example of how radionuclides can be distributed within a mineral specimen, showing the variability of the depth of these included sources. There is an excellent picture of my knee on one of the slides.
Hi Charles, cool observation. If I may guess at it:
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
So your method might show up something that an external exciter misses.
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further
inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though
it looked quite uniform.
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain
to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
That's a great representation of the inclusions Steve.?
Is the X-Ray mapping done with electrons on an SEM or some other? Looks really cool. Also the photomicrographs. Do you have your own inverted microscope?
One thing I use the X-Ray viewer for it to trace veins inside rocks so I know where to look with other devices. Nothing fancy, pretty basic stuff.
----- Original Message ----- From: WILLIAM S Dubyk <sdubyk@...> To: [email protected] Sent: Fri, 07 Feb 2020 21:15:05 -0500 (EST) Subject: Re: [XRF] The case of the missing elements
Attached is an example of how radionuclides can be distributed within a mineral specimen, showing the variability of the depth of these included sources. There is an excellent picture of my knee on one of the slides.
Hi Charles, cool observation. If I may guess at it:
We know from experience that an atom will make XRF if excited by energy from alpha, beta (or electron stream) Gamma, X-Rays etc. Probably many other ways too.
So if you rely on internal energy to do this, it will do so in response to the available radiation from the rock. Some have LOTS, some have very little, some almost none.
One advantage to that way is all the atoms, even those deep within a big rock are being excited. If those XRF rays can get out depends only on the energy of the ray and the overburden.
Rays above 50 keV have little problem penetrating silicon-calcium-oxygen atoms.
This goes for adding external energy or gathering internally generated XRF.
So your method might show up something that an external exciter misses.
But a good exciter will work on a rock that has no discernable radioactivity, the thing is how radioactive is the rock and how radioactive is does the external exciter have to be to equal or better it.....
The pro units have a need for speed so they have X-Ray tubes, blasting the sample with as much as the law allows. We don't actually have a need for speed so we can use tiny little exciters, but as far as the elements at the surface and a little further inside are concerned, it is much more "exciting" than the stuff coming from deep inside and spread over the entire surface of the rock.
In other words it may be small, but it is concentrated where it counts, we substitute long run times to get the results we need.
Say on another note, do you have enough Trinitite to do some Gamma Spec runs on it with your Si-PIN? You could precisely calibrate the detector with Am, the see if the X-Rays coming from Trinitite are from Np or U atoms, or both.
I recently picked up a specimen of melanocerite-Ce at the mineral show and did a scan without Am241 by depending on the internal radiation.? I was not surprised to see Th La Ce and Nd in the blue plot.
Then I wanted to see if I got the same results using Am241 as an additional exciter.? So I carefully moved the specimen just far enough from the detector to allow me to slide in the Am241 jig.? I was careful to keep the same spot on the rock even though it looked quite uniform.
Curiously I am now getting additional strong Fe and Y peaks in the red plot.? What could account for this?? I am not surprised that the La Ce Nd are lit up as they are.
I have also attached both .mca files in case one wishes to analyze them.? However, I am not really asking for that.? I would just like to understand why the Am241 lights up the Fe and Y so strongly compared to the internal radiation.? It is kind of a pain to weed through the Am241 background peaks but it appears that I may not get a complete picture with the internal radiation alone.
