Re: Li battery shiny vs dull
Cool, that's a beast compared to mine. Max is 0.1 mA (100 microamp) here.
It does have its own shielded housing, and I suspect the narrow measured beam cone angle is controlled by an mechanical iris inside the sealed tube. I'm assuming yours is also a side exit not and end-fire, those use transmission targets, the kind I use have "reflection" tungsten targets.? The excitation HV is less than the W Ka, so all I work with are Bremsstrahlung X-Rays, thus the external filtering etc.
Geo
----- Original Message ----- From: Dude <dfemer@...> To: [email protected]Sent: Sun, 09 Feb 2020 15:30:33 -0500 (EST) Subject: Re: [XRF] Li battery shiny vs dull
Geo, My Kevex¡¯s are PXS4-613W and ?run with a CU015 60 kV power supply. Target Voltage:? 5.0 to 60.0 kV Current:? 0.01 to 1.00 mA X-ray source spot size: 0.01¡± x 0.020¡± (0.25mm x 0.45 mm)
Approximately X-ray Output: 101R/min at 60 watts X-ray Window: 0.005¡± (0.13mm) Be Angle of illumination: 35 degrees inclusive (Approx) ? When you first fire it up or when it¡¯s been sitting for a long
while ramp up the voltage in 20% steps at 10 % of max current steps ?to allow
the tube to outgas. Do this over a 10- to 15 min period (1 minute minimum at
each step) before going to full power. Watch out for arcing. ?Don¡¯t run
prolonged operation at 5kV or less at high beam current as that will run the filament
hotter than normal and will decrease the filament life. They warn that the X-rays are dangerous and ?may be fatal. The
X-ray tube window must be placed in a shielded chamber. It¡¯s also clearly stated
not to let anyone named Geo operate this machinery. Dud ? ? Geo, I have the specs here someplace but I don¡¯t remember exactly. 16
seems about right and the microfocus spot was very small as I remember. I¡¯ll dig around and see f I can find the manual ? ? That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
have a 16 degree cone- does that sound right?
|
Re: Li battery shiny vs dull
Geo,
My Kevex¡¯s are PXS4-613W and ?run with a CU015 60 kV power supply.
Target Voltage:? 5.0 to 60.0 kV
Current:? 0.01 to 1.00 mA
X-ray source spot size: 0.01¡± x 0.020¡± (0.25mm x 0.45 mm)
Approximately
X-ray Output: 101R/min at 60 watts
X-ray Window: 0.005¡± (0.13mm) Be
Angle of illumination: 35 degrees inclusive (Approx)
?
When you first fire it up or when it¡¯s been sitting for a long
while ramp up the voltage in 20% steps at 10 % of max current steps ?to allow
the tube to outgas. Do this over a 10- to 15 min period (1 minute minimum at
each step) before going to full power. Watch out for arcing. ?Don¡¯t run
prolonged operation at 5kV or less at high beam current as that will run the filament
hotter than normal and will decrease the filament life.
They warn that the X-rays are dangerous and ?may be fatal. The
X-ray tube window must be placed in a shielded chamber. It¡¯s also clearly stated
not to let anyone named Geo operate this machinery.
Dud
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of Dude
Sent: Sunday, February 9, 2020 11:54 AM
To: [email protected]
Subject: Re: [XRF] Li battery shiny vs dull
?
Geo,
I have the specs here someplace but I don¡¯t remember exactly. 16
seems about right and the microfocus spot was very small as I remember.
I¡¯ll dig around and see f I can find the manual
?
?
That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
have a 16 degree cone- does that sound right?
|
Re: Li battery shiny vs dull
No biggie Dud, My figures indicated that the focal spot of the electron beam, whatever size it actually is,? is approximately 1" from the outer edge of the brass collimator on the outer housing, and that sounds credible.
Geo
----- Original Message ----- From: Dude <dfemer@...> To: [email protected]Sent: Sun, 09 Feb 2020 14:54:15 -0500 (EST) Subject: Re: [XRF] Li battery shiny vs dull
Geo, I have the specs here someplace but I don¡¯t remember exactly. 16
seems about right and the microfocus spot was very small as I remember. I¡¯ll dig around and see f I can find the manual ? ? That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
have a 16 degree cone- does that sound right?
|
Re: Li battery shiny vs dull
Geo,
I have the specs here someplace but I don¡¯t remember exactly. 16
seems about right and the microfocus spot was very small as I remember.
I¡¯ll dig around and see f I can find the manual
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Sunday, February 9, 2020 10:53 AM
To: [email protected]
Subject: Re: [XRF] Li battery shiny vs dull
?
That
sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot
size and the cone angle? The one in my rig here in the counting room seems to
have a 16 degree cone- does that sound right?
|
Re: Li battery shiny vs dull
The scans that I posted show only Cr Fe and Ni.? Of course, I can't see Li in any case.
Those cheap batteries used to have a nice zinc case,? carbon rod and a lot of MnO2.?
The manganese dioxide is a catalyst to decompose hydrogen peroxide into water and O2, which reacts with calcium carbide to make a mixture of O2 and acetylene. Fun to play with but highly flammable.?
The carbon rods make great,? well,? electrodes, for all kinds of things.? Arc lamps,? electrolysis,? etc.
Zinc good for pyrotechnics, electrolysis,? nontoxic aquarium plant weights...
PS, Charles and all, keep a dead dry cell flashlight battery (the cheap kind). Take it apart for elements for your collection, a few of which also make perfect XRF calibration sources.
Geo
Just for fun I tested both sides of a Li battery.? One side (+) is shiny and engraved and the other side is dull (-).? After doing the shiny side (red) for a couple of hours I started the dull side and unfortunately let it run overnight so the counts are disproportionately high.? However, close inspection of the 2 graphs show that the shiny side has much more Cr than the dull side.? In fact, whatever Cr shows up in the blue graph may actually be coming from the edges of the battery where the shiny side wraps around.
So my question is whether there is an electrical reason for the Cr on the + side or is it purely cosmetic?
Charles
|
Re: Li battery shiny vs dull
Those cheap batteries used to have a nice zinc case,? carbon rod and a lot of MnO2.?
The manganese dioxide is a catalyst to decompose hydrogen peroxide into water and O2, which reacts with calcium carbide to make a mixture of O2 and acetylene. Fun to play with but highly flammable.?
The carbon rods make great,? well,? electrodes, for all kinds of things.? Arc lamps,? electrolysis,? etc.
Zinc good for pyrotechnics, electrolysis,? nontoxic aquarium plant weights...
PS, Charles and all, keep a dead dry cell flashlight battery (the cheap kind). Take it apart for elements for your collection, a few of which also make perfect XRF calibration sources.
Geo
Just for fun I tested both sides of a Li battery.? One side (+) is shiny and engraved and the other side is dull (-).? After doing the shiny side (red) for a couple of hours I started the dull side and unfortunately let it run overnight so the counts are disproportionately high.? However, close inspection of the 2 graphs show that the shiny side has much more Cr than the dull side.? In fact, whatever Cr shows up in the blue graph may actually be coming from the edges of the battery where the shiny side wraps around.
So my question is whether there is an electrical reason for the Cr on the + side or is it purely cosmetic?
Charles
|
Re: Li battery shiny vs dull
That sounds logical Dud, hey on your Kevex stand alone tube, do you know the spot size and the cone angle? The one in my rig here in the counting room seems to have a 16 degree cone- does that sound right?
Geo>K0FF
----- Original Message ----- From: Dude <dfemer@...> To: [email protected], 'Mike Loughlin' <loughlin3@...> Sent: Sun, 09 Feb 2020 12:03:17 -0500 (EST) Subject: Re: [XRF] Li battery shiny vs dull
A Cr coated anode gives the battery a better discharge capacity
and is more stable during cycling. Dud ? ? ? Just for fun I tested both sides of a Li battery.? One
side (+) is shiny and engraved and the other side is dull (-).? After
doing the shiny side (red) for a couple of hours I started the dull side and
unfortunately let it run overnight so the counts are disproportionately
high.? However, close inspection of the 2 graphs show that the shiny side
has much more Cr than the dull side.? In fact, whatever Cr shows up in the
blue graph may actually be coming from the edges of the battery where the shiny
side wraps around. So my question is whether there is an electrical reason for
the Cr on the + side or is it purely cosmetic?
|
Re: Li battery shiny vs dull
The anode is Li and the Cr ?has a high Li storage capacity.? Did
you see any V or Ti in that shot? They are sometimes used in the Cr coatings.
dud
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of Charles David Young
Sent: Sunday, February 9, 2020 9:26 AM
To: [email protected]
Subject: Re: [XRF] Li battery shiny vs dull
?
That is interesting, Dud.? So why is that the case and
why only the anode?
?
On Sun, Feb 9, 2020 at 10:03 AM Dude <dfemer@...> wrote:
A Cr
coated anode gives the battery a better discharge capacity and is more stable
during cycling.
Dud
?
?
?
Just
for fun I tested both sides of a Li battery.? One side (+) is shiny and
engraved and the other side is dull (-).? After doing the shiny side (red)
for a couple of hours I started the dull side and unfortunately let it run
overnight so the counts are disproportionately high.? However, close inspection
of the 2 graphs show that the shiny side has much more Cr than the dull
side.? In fact, whatever Cr shows up in the blue graph may actually be
coming from the edges of the battery where the shiny side wraps around.
So
my question is whether there is an electrical reason for the Cr on the + side
or is it purely cosmetic?
|
Re: Li battery shiny vs dull
That is interesting, Dud.? So why is that the case and why only the anode?
Charles
On Sun, Feb 9, 2020 at 10:03 AM Dude < dfemer@...> wrote:
A Cr coated anode gives the battery a better discharge capacity
and is more stable during cycling.
Dud
?
?
?
Just for fun I tested both sides of a Li battery.? One
side (+) is shiny and engraved and the other side is dull (-).? After
doing the shiny side (red) for a couple of hours I started the dull side and
unfortunately let it run overnight so the counts are disproportionately
high.? However, close inspection of the 2 graphs show that the shiny side
has much more Cr than the dull side.? In fact, whatever Cr shows up in the
blue graph may actually be coming from the edges of the battery where the shiny
side wraps around.
So my question is whether there is an electrical reason for
the Cr on the + side or is it purely cosmetic?
|
Re: Li battery shiny vs dull
A Cr coated anode gives the battery a better discharge capacity
and is more stable during cycling.
Dud
?
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of Charles David Young
Sent: Sunday, February 9, 2020 6:37 AM
To: [email protected]; Mike Loughlin
Subject: [XRF] Li battery shiny vs dull
?
Just for fun I tested both sides of a Li battery.? One
side (+) is shiny and engraved and the other side is dull (-).? After
doing the shiny side (red) for a couple of hours I started the dull side and
unfortunately let it run overnight so the counts are disproportionately
high.? However, close inspection of the 2 graphs show that the shiny side
has much more Cr than the dull side.? In fact, whatever Cr shows up in the
blue graph may actually be coming from the edges of the battery where the shiny
side wraps around.
So my question is whether there is an electrical reason for
the Cr on the + side or is it purely cosmetic?
|
Hi Dave, yes I think so. That's not what I'm doing but just by coincidence the 32 keV from Cs-137 decay is still very evident. We can assume the 662 is there too, I'm just not looking that high.
Now that we finally have access to high resolution room temp sensors, we can delve a little deeper into the X-rays and maybe make some conclusions.
Is anyone presently here deep into Trinitite analysis? (Gamma or XRF either one)
Geo>K0FF
----- Original Message ----- From: David Eckhardt <davearea51a@...> To: [email protected]Sent: Sat, 08 Feb 2020 19:49:37 -0500 (EST) Subject: Re: [XRF] Trinitite
Are you still able to get a meaningful spectrum from the trinitite with amateur probes?? It's over 70 years old.
I had a piece which was given to dad in the mid 50's.? His boss collected it shortly after the 'event' at Trinity before everything was plowed under.? I remember at the time, the clicking from it would get your attention with a CK1026 glass GM tube (home brew GM detector).? Over the years, I tracked its diminishing activity (with better instruments).? Wish I still had it, but lost in the 2012 forest fire.
Dve - W ?LEV
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.
Geo>K0FF
?
--
Dave - W?LEV
Just Let Darwin WorkJust Think
|
Re: Li battery shiny vs dull
PS, Charles and all, keep a dead dry cell flashlight battery (the cheap kind). Take it apart for elements for your collection, a few of which also make perfect XRF calibration sources.
Geo
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: [email protected], Mike Loughlin <loughlin3@...> Sent: Sun, 09 Feb 2020 09:36:42 -0500 (EST) Subject: [XRF] Li battery shiny vs dull
Just for fun I tested both sides of a Li battery.? One side (+) is shiny and engraved and the other side is dull (-).? After doing the shiny side (red) for a couple of hours I started the dull side and unfortunately let it run overnight so the counts are disproportionately high.? However, close inspection of the 2 graphs show that the shiny side has much more Cr than the dull side.? In fact, whatever Cr shows up in the blue graph may actually be coming from the edges of the battery where the shiny side wraps around.
So my question is whether there is an electrical reason for the Cr on the + side or is it purely cosmetic?
Charles
|
Re: Li battery shiny vs dull
Interesting question, and I don't know. There very may be electro-chemical reasons, for example 316 stainless has a lot better sodium corrosion resistance than 304 ss.
Just a wild guess but the polarity may have something to do with the choice of alloy.
Intriguing.
Speaking of alloys Charles, try analyzing the metals used in a household incandescent bulb- a tremendous amount of research in materials led to metals with just the right mechanical/physical compatibilities.
Good question, based upon a really good observation.
Geo
----- Original Message ----- From: Nick Andrews <nickjandrews@...> To: [email protected]Sent: Sun, 09 Feb 2020 10:59:11 -0500 (EST) Subject: Re: [XRF] Li battery shiny vs dull
Probably just more Cr in the alloy used.? Possibly for corrosion resistance.? Or the metal on that side is thicker,? as it's the primary casing of the unit.?
Just for fun I tested both sides of a Li battery.? One side (+) is shiny and engraved and the other side is dull (-).? After doing the shiny side (red) for a couple of hours I started the dull side and unfortunately let it run overnight so the counts are disproportionately high.? However, close inspection of the 2 graphs show that the shiny side has much more Cr than the dull side.? In fact, whatever Cr shows up in the blue graph may actually be coming from the edges of the battery where the shiny side wraps around.
So my question is whether there is an electrical reason for the Cr on the + side or is it purely cosmetic?
Charles
|
Re: Li battery shiny vs dull
Probably just more Cr in the alloy used.? Possibly for corrosion resistance.? Or the metal on that side is thicker,? as it's the primary casing of the unit.?
Just for fun I tested both sides of a Li battery.? One side (+) is shiny and engraved and the other side is dull (-).? After doing the shiny side (red) for a couple of hours I started the dull side and unfortunately let it run overnight so the counts are disproportionately high.? However, close inspection of the 2 graphs show that the shiny side has much more Cr than the dull side.? In fact, whatever Cr shows up in the blue graph may actually be coming from the edges of the battery where the shiny side wraps around.
So my question is whether there is an electrical reason for the Cr on the + side or is it purely cosmetic?
Charles
|
Just for fun I tested both sides of a Li battery.? One side (+) is shiny and engraved and the other side is dull (-).? After doing the shiny side (red) for a couple of hours I started the dull side and unfortunately let it run overnight so the counts are disproportionately high.? However, close inspection of the 2 graphs show that the shiny side has much more Cr than the dull side.? In fact, whatever Cr shows up in the blue graph may actually be coming from the edges of the battery where the shiny side wraps around.
So my question is whether there is an electrical reason for the Cr on the + side or is it purely cosmetic?
Charles
|
Re: The case of the missing elements
toggle quoted message
Show quoted text
----- Original Message ----- From: Dude <dfemer@...> To: [email protected]Sent: Sat, 08 Feb 2020 23:13:48 -0500 (EST) Subject: Re: [XRF] The case of the missing elements
Geo, Jaw crusher, 110v motor, weights about 200lbs on a stand. It sits
in the mancave and its easier to bring rocks to it than it to rocks. Dud ? ? ? ? "I use a Rock crusher for big rock samples" Pics? Manual?
Portable (trailer hitch mount)? -----
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
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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.? ?Dud
? 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 Dud ? ? ? ? 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. -----
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.
|
Re: The case of the missing elements
Geo,
Jaw crusher, 110v motor, weights about 200lbs on a stand. It sits
in the mancave and its easier to bring rocks to it than it to rocks.
Dud
?
?
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Saturday, February 8, 2020 9:16 AM
To: [email protected]
Subject: Re: [XRF] The case of the missing elements
?
"I use a Rock crusher for big rock samples" Pics? Manual?
Portable (trailer hitch mount)?
-----
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
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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.?
?Dud
?
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
Dud
?
?
?
?
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.
-----
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.
|
Re: The case of the missing elements
A Pellet press is commonly used for FTIR, LIBS and XRF. It¡¯s
expensive to get set up though. I am just getting set up with a 12 ton press and
the die¡¯s for my LIBS system. ?The problem is you can¡¯t use a powder sample for
?LIBS as the laser pulse blows the sample all over the place. ?It needs to be a
tough solid pellet.
I use either an iron or ceramic mortar and pestle for pulverizing
the small samples.
Dud
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Saturday, February 8, 2020 9:13 AM
To: [email protected]
Subject: Re: [XRF] The case of the missing elements
?
"
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.
?
Geo
?
?
?
?
-----
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
margin-top: 0;
margin-bottom: 0;
}
/*]]>*/
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
Dud
?
?
?
?
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.
----- 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.
|
Re: The case of the missing elements
Steve,
A XRF cup is 2.5 cm in dia and 2 cm deep. Its filled about halfway
and a cotton ball is placed in the back pressing the powder against the mylar
film. It uses about 10 to 15 grams or so to about half full.? You want the
sample to be thick enough so it¡¯s an infinite thickness for the x-rays.
You don¡¯t need much in size as the X-ray beam dia is small
it just needs to expose some fraction of the cup surface.
Dud
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of WILLIAM S Dubyk.
Sent: Saturday, February 8, 2020 7:19 AM
To: [email protected]
Subject: Re: [XRF] The case of the missing elements
?
How
many grams of material for an adequate sample?
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.?
?Dud
?
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
Dud
?
?
?
?
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.
-----
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.
|
Are you still able to get a meaningful spectrum from the trinitite with amateur probes?? It's over 70 years old.
I had a piece which was given to dad in the mid 50's.? His boss collected it shortly after the 'event' at Trinity before everything was plowed under.? I remember at the time, the clicking from it would get your attention with a CK1026 glass GM tube (home brew GM detector).? Over the years, I tracked its diminishing activity (with better instruments).? Wish I still had it, but lost in the 2012 forest fire.
Dve - W ?LEV
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.  Geo>K0FF ?
-- Dave - W?LEV
Just Let Darwin WorkJust Think
|
Nick Andrews
