|
Geo,
I
don’t see how normalizing accounts for flux? There are 2 different count times
and 2 different activities? And a filter. The 1.6 mm Al “filter” will drop the flux
by a factor of 0.5. The count times are different by a factor of 4.5, and there
is an unknown activity difference. If you count for the same times then the
peak count differences will be the activity ratio (with all other things equal).
Peak counts must be corrected for the source activity to compare the two. ?Putting
an Al filter in there is just an attenuator and only addresses the low energy
range below Al binding energy. Most filters are 100s of microns thick and are
tailored to a small energy range to kill the tube background and allow lower
limits of detection in that smaller energy range. 1.6 mm at 59 keV would act as
an overall attenuator
The
C0-57would be nice but ?has a bad $/half like ratio what about a Ba133 which would
get 80 keV + or a Eu 154 at 123KEv + ?
?
The
question I had was your photo showed a Peak Time of “rise? value” I wonder how that
got in there.
K’s
are stronger if you can get 'em and they have less interference, but the
heavies are tough? to get
Dud
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From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Monday, October 26, 2020 12:45 PM
To: [email protected]
Subject: Re: [XRF] 59.5keV spectrum cleanup
?
-----
Original Message -----
From: Dude <dfemer@...>
To: [email protected]
Sent: Mon, 26 Oct 2020 13:27:01 -0400 (EDT)
Subject: Re: [XRF] 59.5keV spectrum cleanup
What
thickness Al filter are you using?
1.6mm
Why normalize to the Am
peak? Just use the same count time to see what the attenuation factor is for
the same source.
So the next?
experiments can use the same flux @ 59.5keV as previous experiments, to
evaluate the positive or negative aspects that the Np X-Rays and other low end
"noise" from the exciter may have . A "monochromic" test at
the expense of run time. This in prep for possible investment in Co-57 source
for K line from heavy elements. At this time?the yield of K vs L lines in
literature doesn't make that seem like a worthy investment.
What
is the Peak Time “rise value”?
Is there another name or
description of that parameter?
RESC=?; Reset Configuration
CLCK=80;
20MHz/80MHz
TPEA=19.200;
Peaking Time
GAIF=1.0238;
Fine Gain
GAIN=18.686;
Total Gain (Analog * Fine)
RESL=204;
Detector Reset Lockout
TFLA=0.600;
Flat Top
TPFA=400; Fast
Channel Peaking Time
PURE=OFF; PUR
Interval On/Off
RTDE=OFF; RTD
On/Off
MCAS=NORM; MCA
Source
MCAC=2048;
MCA/MCS Channels
SOFF=OFF; Set
Spectrum Offset
AINP=NEG;
Analog Input Pos/Neg
INOF=DEF; Input
Offset
GAIA=14; Analog
Gain Index
CUSP=0;
Non-Trapezoidal Shaping
PURS=??;
Secondary PUR
PDMD=NORM; Peak
Detect Mode (Min/Max)
THSL=0.878;
Slow Threshold
TLLD=OFF; LLD
Threshold
THFA=53.12;
Fast Threshold
DACO=SHAPED;
DAC Output
DACF=50; DAC
Offset
RTDS=0; RTD
Sensitivity
RTDT=0.00; RTD
Threshold
BLRM=1; BLR Mode
BLRD=3; BLR
Down Correction
BLRU=0; BLR Up
Correction
GATE=OFF; Gate
Control
AUO1=SCA8;
AUX_OUT Selection
PRET=2370.0;
Preset Time
PRER=OFF;
Preset Real Time
PREC=OFF;
Preset Counts
PRCL=1; Preset
Counts Low Threshold
PRCH=8191;
Preset Counts High Threshold
HVSE=190; HV Set
TECS=230; TEC
Set
PAPS=ON; Preamp
8.5/5 (N/A)
SCOE=FA; Scope
Trigger Edge
SCOT=12; Scope
Trigger Position
SCOG=1; Digital
Scope Gain
MCSL=1; MCS Low
Threshold
MCSH=8191; MCS
High Threshold
MCST=0.01; MCS
Timebase
AUO2=ICR;
AUX_OUT2 Selection
TPMO=OFF; Test
Pulser On/Off
GPED=RI; G.P.
Counter Edge
GPIN=AUX1; G.P.
Counter Input
GPME=ON; G.P.
Counter Uses MCA_EN?
GPGA=ON; G.P.
Counter Uses GATE?
GPMC=ON; G.P.
Counter Cleared With MCA Counters?
MCAE=OFF;
MCA/MCS Enable
BOOT=ON; Turn
Supplies On/Off At Power Up
Good
luck with the total reflection it’s a complicated set up.
Dud
?
?
Obviously the Pyro is much
cleaner. Mostly due to the added filters and other manufacturing differences
between
vintage low volume commercial productions vs. today's mass produced but more
safety minded production. These are thin, flat metal strips that could be taped
into position. CAVEAT- RISK FACTOR-These have been know to leak/shed. Please
don't use without a permanent Kapton or Mylar tape protective layer.
To reduce the low end energy even further, some aluminum filters were placed
between the pyro source and the sensor. Time for the scan is adjusted so the
59.5 peak is the same for both?
?
The pictures I think are striking. This will be the exciter source used for the
next series of experiments into what is called "Grazing Angle Total
Reflection XRF"" or "Edge XRF". In this method the sample
being tested for elemental content is placed edge-wise (90 degrees) to the
sensor vs. face to face, and the exciter is at right angles to the sample, thus
the "grazing angle" of excitation and the readout is gathered from
the edge of the target.
There are a number of studies being done on TR-XRF, but the search term
most?
fertile will include the term "grazing angle".
Filters remove most of the low energy component, leaving the 59.5 the same
(time adjusted)
Here is the comparison of what we have been using and the difference that can
be achieved:
The included Gamma Spectrum mode .mca files were all done with the newly
adopted 19.2us peaking time.
Some things achieved by that study thanks to suggestions of members:
Deadtime virtually eliminated.
Low end "electronic noise" virtually eliminated.
Resolution improved.
Speed of which the pattern forms improved.
Overall "look" of the scan improved.
Geo
|
" Geo,
I don’t see how normalizing accounts for flux?"
In X-Ray jargon, what I'm doing is applying a "hardening filter" to the X-Ray beam from the exciter. In this case the exciter is a radioisotope, not a tube. Here's a link to the book From which this chart comes. It explains how at 13.95 keV, 1mm Al allows only 10% penetration, while at 59.5 keV it allows 90% penetration. If the low energies are harmful to our studies, it's no sacrifice to kill them / If they are helpful, then we will keep them and put up with the interference. Especially in the amateur lab where we have plenty of time and little else to spare. Geo 
|
Geo,
Actually
this is for knocking down broad energy x-rays so the skin doesn’t get burned
and you get a good x-ray by passing portions of the higher energy through to
the target. The x-ray tube has a broad energy range while you have a monochromatic
source.
The
reduction in flux will be determined by the energy, density and thickness of
the material.? You use the linear attenuation coefficient or the mass attenuation
coefficient to calculate the reduction in intensity using:
I=Io*e^(-ux)
Where
x is the thickness in cm of the material
u
is the linear attenuation coefficient
And
Io is the original intensity or counts, cps, or just a unit 1 if you want the
reduction factor
You
can look up u in the NIST tables. https://physics.nist.gov/PhysRefData/XrayMassCoef/ElemTab/z13.html
For
Al at 60 keV it’s u/p is 2.778E-1 cm^2/g. To get the u just multiply by the
density of Al = 2.70 g/cm^3 giving u= 0.75/cm ?and the x = thickness of 1.6mm
Al (0.016 cm)
So
I = 1*e^(-0.75 * 0.016) = 0.99? or just about all of it gets through and because
its monochromatic there is no benefit from a low energy absorption edge to act
as a low energy filter.
Dud
?
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From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Monday, October 26, 2020 6:24 PM
To: [email protected]
Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
?
"Geo,
I don’t see how normalizing accounts for flux?"
In X-Ray jargon, what I'm doing is applying a "hardening
filter" to the X-Ray beam from the exciter. In this case the exciter is a
radioisotope, not a tube.
Here's a link to the book
From which this chart comes. It explains how at 13.95 keV, 1mm Al allows only
10% penetration, while at 59.5 keV it allows 90% penetration.
If the low energies are harmful to our studies, it's no sacrifice to kill them
/ If they are helpful, then we will keep them and put up with the interference.
Especially in the amateur lab where we have plenty of time and little else to
spare. Geo
|
"The x-ray tube has a broad energy range while you have a monochromatic source."
Something is not right here Dud. We WANT a monoenergetic source, we don't HAVE a monoenergetic source. That's the point of the experiment.
?
This is the source we all have, it is not monochromatic:
?
|
We're using the same chart, just drawn differently. Here's the NIST standard chart that I marked up. The filters you refer to a K-edge filters, what I'm doing is above the K-edge. In radio-electronic terms, a K-edge filter is a sharp cutoff filter, while in the range of X-Rays we use, the filter would be called a high-pass filter.  Every element has a similar curve, but with a unique K-edge, and at the plateau area (the bottom of the chart above and to top of the first chart I posted) there is a point of energy where any increase in energy no longer changes the attenuation factor.
|
Geo,
These
Am and Np peaks are monochromatic having discrete energies not the broad bremsstrahlung
you get from a X-ray tube. The tube’s characteristic lines are also monochromatic.
The
issue is getting rid of the Np lines which van be done with a source filter. To
optimize the 13 – 17keV range of the Np lines from the source you would use 150
um Cu , 25 um Ti, and a 300 um Al filter. At 20 keV just a 0.3mm Al filter
would reduce that original count to 6%. At 17 keV it would be a 1% reduction. ?Remember
that the Np lines are also acting as a source for xrf of the lower Z ?elements.
When using a tube source you would run 3 tube voltages 50, 40 and 15 or so to the
maximize each energy region of interest.
?
Dud
?
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Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Tuesday, October 27, 2020 5:48 AM
To: [email protected]
Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
?
"The x-ray tube has a broad energy range while you have a
monochromatic source."
Something is not right here Dud. We WANT a monoenergetic source, we don't HAVE
a monoenergetic source. That's the point of the experiment.
This is the source we all have, it is not monochromatic:
|
Not a bad trial for a quicky. The ratio of 59.5 to the lows really changed. Needs tweaking this end. 
|
Geo,
We
know you know what you’re doing but none of us know what you were doing. Please
also be descriptive in what we’re looking at. Pretty pictures don’t do much
without context. Write the experiment up
What
the objective, what filter, where, with what metal, what thickness, what target,
what source, count times? What’s an edge filter?
Dud
?
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From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Tuesday, October 27, 2020 1:21 PM
To: [email protected]
Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
?
Not a bad trial for a quicky. The ratio of 59.5 to the lows
really changed. Needs tweaking this end.
|
Here's a better demonstration test. An 1800sec scan was made using a single Am button, pointed directly at the Si-PIN detector Next the filter stack (Al-Ti-CU) was placed between the source and the Si-PIN. This test was ran until the 59.5 peaks matched (1500s), as this is the area of interest. There was dramatic effect on the Np- X-Rays. Fault- did pick up Cu XRF from filter. Next time will reverse the order of the sheets in the stack, keeping copper more towards the source. Geo 
|
Actually
there not much we can do for looking at the Am button as a sample. What the source
filter is designed for is using the Am buttons as a source where we need to get
rid of the Np interferences and how to optimize that.
What
thickness’s were you using? Try this filter on an Am source and a mid to low Z target
sample with and without the filter.
Dud
?
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Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Tuesday, October 27, 2020 2:28 PM
To: [email protected]
Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
?
Here's a better demonstration test.
An 1800sec scan was made using a single Am button, pointed directly at the
Si-PIN detector
Next the filter stack (Al-Ti-CU) was placed between the source and the Si-PIN.
This test was ran until the 59.5 peaks matched (1500s), as this is the area of
interest.
There was dramatic effect on the Np- X-Rays.
Fault- did pick up Cu XRF from filter. Next time will reverse the order of the
sheets in the stack, keeping copper more towards the source.
Geo
|
No but we're analyzing it's ray pattern.
Here's the next step, it's a redo of the Source Filter test (which I built close to but not exactly to your specifications, will clean that up later in the shop) with the Cu close to the source rather than the sensor side, allowing the Ti and Al to attenuate the cu characteristic X-Rays that showed up on the last plot.
More tests tomorrow, this has been real-time, making adjustments per recommendations.
Great fun
PS in between these trials, the Ba-133 testing was running on another instrument. Will post that tomorrow. Looks good.
Geo
|
This
will be interesting, What thicknesses are you running on these?
Dud
?
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Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of GEOelectronics@...
Sent: Tuesday, October 27, 2020 3:00 PM
To: [email protected]
Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
?
No but we're analyzing it's ray pattern.
Here's the next step, it's a redo of the Source Filter test (which I built
close to but not exactly to your specifications, will clean that up later in
the shop) with the Cu close to the source rather than the sensor side, allowing
the Ti and Al to attenuate the cu characteristic X-Rays that showed up on the
last plot.
More tests tomorrow, this has been real-time, making adjustments per
recommendations.
Great fun
PS in between these trials, the Ba-133 testing was running on another
instrument. Will post that tomorrow. Looks good.
Geo
|
After trying many slight thickness variations of Source Filter components, the best result is show in the second picture. First up is the spectra coming out of the Am exciter source with just a paper alpha blocking filter. That alone made significant improvements at the low end vs no alpha filter. The goal of this project is to apply a filter to the source that will effectively remove most of the low energy component that is caused by Np- daughter and self-XRF of elements in the button, such as Au, Ag, Fe.  Now a filter applied to the source and another Gamma Spectrum ran.  Thanks to member Dudley Emer for the design of the filter elements and thicknesses, based on selective filtering using the K-edge X-Ray absorption effect. Geo
|
The filter comes at a cost.? Am I reading it correctly that it reduced the input count to %25 of the non-filtered?? Do we need to wait 4x longer for equal counts when this is used as an exciter?? Was all that low energy activity that is filtered out detrimental or beneficial when the button is used to stimulate XRF in the target?
I come at this from a different perspective.? I use the Si-PIN with an Am241 exciter to identify minerals.? In my experience the XRF coming from the target is much stronger than the noise introduced by the Am241, which is mounted on a shield and facing away from the detector.? Attached is a scan of xenotime, which shows a large Y component as well as some U and Pb.? I turned on the Am241 reference lines to show that the Np and Au peaks are very small in comparison.? One quickly learns to recognize and ignore them when identifying the important peaks that emanate from the target: Ti, Mn, Fe, Ta, Th, U, Y, Zr, Nb, REEs.
Charles
After trying many slight thickness variations of Source Filter components, the best result is show in the second picture. First up is the spectra coming out of the Am exciter source with just a paper alpha blocking filter. That alone made significant improvements at the low end vs no alpha filter. The goal of this project is to apply a filter to the source that will effectively remove most of the low energy component that is caused by Np- daughter and self-XRF of elements in the button, such as Au, Ag, Fe.  Now a filter applied to the source and another Gamma Spectrum ran.  Thanks to member Dudley Emer for the design of the filter elements and thicknesses, based on selective filtering using the K-edge X-Ray absorption effect. Geo
|
"The filter comes at a cost.? Am I reading it correctly that it reduced the input count to %25 of the non-filtered?? Do we need to wait 4x longer for equal counts when this is used as an exciter? "
All that is to be determined Charles. It well may be much worse than that, if the low energies in the beam are what's helping to dig out the low energy XRF signals we are looking for.
I agree about our perspective points of view too.?
You system is as ideal as can be for your main task, and your display program is an advancement in the area of display and identification, especially for the audience of that group. Now the photography meets the same standard too. No one has added all those dimensions in one place to the amateur mineral group before.? All for science' sake, and I applaud that.
For you and others I would recommend trying a paper filter over the exciter source, just to see.
The rest is for the X-Ray Physics and X-Ray Optics crowd. We now have an inexpensive but powerful tool in our toolbox that wasn't there 2 days ago.
Geo
----- Original Message ----- From: Charles David Young <charlesdavidyoung@...> To: XRF < [email protected]> Sent: Wed, 28 Oct 2020 08:33:01 -0400 (EDT) Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
The filter comes at a cost.? Am I reading it correctly that it reduced the input count to %25 of the non-filtered?? Do we need to wait 4x longer for equal counts when this is used as an exciter?? Was all that low energy activity that is filtered out detrimental or beneficial when the button is used to stimulate XRF in the target?
I come at this from a different perspective.? I use the Si-PIN with an Am241 exciter to identify minerals.? In my experience the XRF coming from the target is much stronger than the noise introduced by the Am241, which is mounted on a shield and facing away from the detector.? Attached is a scan of xenotime, which shows a large Y component as well as some U and Pb.? I turned on the Am241 reference lines to show that the Np and Au peaks are very small in comparison.? One quickly learns to recognize and ignore them when identifying the important peaks that emanate from the target: Ti, Mn, Fe, Ta, Th, U, Y, Zr, Nb, REEs.
Charles
After trying many slight thickness variations of Source Filter components, the best result is show in the second picture.
First up is the spectra coming out of the Am exciter source with just a paper alpha blocking filter. That alone made significant improvements at the low end vs no alpha filter. The goal of this project is to apply a filter to the source that will effectively remove most of the low energy component that is caused by Np- daughter and self-XRF of elements in the button, such as Au, Ag, Fe.
Now a filter applied to the source and another Gamma Spectrum ran.
Thanks to member Dudley Emer for the design of the filter elements and thicknesses, based on selective filtering using the K-edge X-Ray absorption effect.
Geo
|
Geo,
I agree and I did not mean to dis this exercise, even if it turns out to be primarily academic.
When I get a chance I'll try the paper filter with a mineral like Brannerite (UTi2O6) to see how it affects the Ti peak at 4.5keV.? That is typically the lowest element that is essential to my application.? Other peaks like P, K, Ca would be nice but I have learned to live without them.? If we could somehow dig those out by an adjustment it would be great.
Charles
"The filter comes at a cost.? Am I reading it correctly that it reduced the input count to %25 of the non-filtered?? Do we need to wait 4x longer for equal counts when this is used as an exciter? "
All that is to be determined Charles. It well may be much worse than that, if the low energies in the beam are what's helping to dig out the low energy XRF signals we are looking for.
I agree about our perspective points of view too.?
You system is as ideal as can be for your main task, and your display program is an advancement in the area of display and identification, especially for the audience of that group. Now the photography meets the same standard too. No one has added all those dimensions in one place to the amateur mineral group before.? All for science' sake, and I applaud that.
For you and others I would recommend trying a paper filter over the exciter source, just to see.
The rest is for the X-Ray Physics and X-Ray Optics crowd. We now have an inexpensive but powerful tool in our toolbox that wasn't there 2 days ago.
Geo
----- Original Message ----- From: Charles David Young < charlesdavidyoung@...> To: XRF < [email protected]> Sent: Wed, 28 Oct 2020 08:33:01 -0400 (EDT) Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
The filter comes at a cost.? Am I reading it correctly that it reduced the input count to %25 of the non-filtered?? Do we need to wait 4x longer for equal counts when this is used as an exciter?? Was all that low energy activity that is filtered out detrimental or beneficial when the button is used to stimulate XRF in the target?
I come at this from a different perspective.? I use the Si-PIN with an Am241 exciter to identify minerals.? In my experience the XRF coming from the target is much stronger than the noise introduced by the Am241, which is mounted on a shield and facing away from the detector.? Attached is a scan of xenotime, which shows a large Y component as well as some U and Pb.? I turned on the Am241 reference lines to show that the Np and Au peaks are very small in comparison.? One quickly learns to recognize and ignore them when identifying the important peaks that emanate from the target: Ti, Mn, Fe, Ta, Th, U, Y, Zr, Nb, REEs.
Charles
After trying many slight thickness variations of Source Filter components, the best result is show in the second picture. First up is the spectra coming out of the Am exciter source with just a paper alpha blocking filter. That alone made significant improvements at the low end vs no alpha filter. The goal of this project is to apply a filter to the source that will effectively remove most of the low energy component that is caused by Np- daughter and self-XRF of elements in the button, such as Au, Ag, Fe. ![Single_Button_Alpha_Blocked_ONLY.png]() Now a filter applied to the source and another Gamma Spectrum ran. ![1-2.5milCu-3Ti-.090Al-Source_Filter.png]() Thanks to member Dudley Emer for the design of the filter elements and thicknesses, based on selective filtering using the K-edge X-Ray absorption effect. Geo
|
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<div>Thickness of the layers of the most aggressive Source Filter Stack (to make it less aggressive, reduce the Cu first then the Ti) </div><div>Cu= .004" = 4mil = 100um</div><div>Ti= .001" = 1 mil = 25um</div><div>Al= .004" = 4mil = 100um</div><div><br data-mce-bogus="1"></div><div>The thinnest copper tried was 2mil, the thinnest Ti was 0.5mil, thinnest Al 4mil (Pepsi can material)<br data-mce-bogus="1"></div><div>Starting at the side the source injects the beam Cu then Ti then Al on the side facing the target, be that a sensor or a target being XRF'ed.</div><div><br data-mce-bogus="1"></div><div><div><br></div><div>The particular order of the elements is required just as we do in graded shielding of Gamma Ray probes and for the same reasons.</div></div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>All worked, it was just the matter of degree of attenuation desired at the lows and tolerable attenuation at 59.5, which is subjective.</div><div><br data-mce-bogus="1"></div><div>This combination of elements relies on the K-edge effect of selective X-Ray absorption at a particular element's K-edge energy, where an abrupt discontinuity exists, all elements having a unique energy. For the curious, yes there are other "edges" for each electron shell.</div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>My first approach was using the more subtle attenuation characteristic curve of only one element - Al (aluminum). This is still of interest and was the first step that would have lead to edge-absorption, but that was going to be in a future chapter. I like to learn by doing, and in a linear way. One step at a time usually.</div><div><br data-mce-bogus="1"></div><div>Geo</div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><br></div><div>----- Original Message -----<br>From: Dude <dfemer@...><br>To: [email protected]<br>Sent: Tue, 27 Oct 2020 19:28:26 -0400 (EDT)<br>Subject: Re: FW: [XRF] 59.5keV spectrum cleanup<br></div><div><br></div><div><style>/*<![CDATA[*/p.MsoNormal, li.MsoNormal, div.MsoNormal {<br> margin: 0.0in;<br> font-size: 12.0pt;<br> font-family: "Times New Roman" , serif;<br>}<br>a:link, span.MsoHyperlink {<br> color: blue;<br> text-decoration: underline;<br>}<br>a:visited, span.MsoHyperlinkFollowed {<br> color: purple;<br> text-decoration: underline;<br>}<br>p {<br> margin-right: 0.0in;<br> margin-left: 0.0in;<br> font-size: 12.0pt;<br> font-family: "Times New Roman" , serif;<br>}<br>p.MsoNoSpacing, li.MsoNoSpacing, div.MsoNoSpacing {<br> margin: 0.0in;<br> font-size: 16.0pt;<br> font-family: Arial , sans-serif;<br> color: black;<br>}<br>span.EmailStyle19 {<br> font-family: Arial , sans-serif;<br> color: black;<br> font-weight: normal;<br> font-style: normal;<br>}<br>*.MsoChpDefault {<br>}<br>div.Section1 {<br> page: Section1;<br>}<br>/*]]>*/</style></div><div class="Section1"><p class="MsoNormal"><span style="font-family: 'arial' , 'sans-serif'; color: black;" data-mce-style="font-family: 'arial' , 'sans-serif'; color: black;">This<br>will be interesting, What thicknesses are you running on these? </span></p><p class="MsoNormal"><span style="font-family: 'arial' , 'sans-serif'; color: black;" data-mce-style="font-family: 'arial' , 'sans-serif'; color: black;">Dud</span></p><p class="MsoNormal"><span style="font-family: 'arial' , 'sans-serif'; color: black;" data-mce-style="font-family: 'arial' , 'sans-serif'; color: black;"> </span></p><div style="border: none; border-top: solid #b5c4df 1pt; padding: 3pt 0in 0in 0in;" data-mce-style="border: none; border-top: solid #b5c4df 1pt; padding: 3pt 0in 0in 0in;"><p class="MsoNormal"><b><span style="font-size: 10pt; font-family: 'tahoma' , 'sans-serif';" data-mce-style="font-size: 10pt; font-family: 'tahoma' , 'sans-serif';">From:</span></b><span style="font-size: 10pt; font-family: 'tahoma' , 'sans-serif';" data-mce-style="font-size: 10pt; font-family: 'tahoma' , 'sans-serif';"> [email protected]<br>[mailto: [email protected]] <b>On Behalf Of </b>GEOelectronics@...<br><b>Sent:</b> Tuesday, October 27, 2020 3:00 PM<br><b>To:</b> [email protected]<br><b>Subject:</b> Re: FW: [XRF] 59.5keV spectrum cleanup</span></p></div><p class="MsoNormal"> </p><p class="MsoNormal">No but we're analyzing it's ray pattern.<br><br><br>Here's the next step, it's a redo of the Source Filter test (which I built<br>close to but not exactly to your specifications, will clean that up later in<br>the shop) with the Cu close to the source rather than the sensor side, allowing<br>the Ti and Al to attenuate the cu characteristic X-Rays that showed up on the<br>last plot.<br><br><br>More tests tomorrow, this has been real-time, making adjustments per<br>recommendations.<br><br><br>Great fun<br><br><br>PS in between these trials, the Ba-133 testing was running on another<br>instrument. Will post that tomorrow. Looks good.<br><br><br>Geo</p><div><p class="MsoNormal"><br></p><br></div></div><div style="color: white;" data-mce-style="color: white;"></div><div><br></div><div><br></div><div><br></div>
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Charles
and Geo
Attach
the mca files so we can look at the data, it’s really hard to interpret
anything from a picture.
The
loss of the low energy Np will be detrimental to xrf of the low energy elements
where it helps to activate them but it will be beneficial to clear up the Np interferences
and allow a better LOD and confirmations for Zr, Mo, Sr, U, Y Nb and others.
Geo
try a shot on a rock target with and without the filter for a long count time.
Lest see what we get difference wise.
Dud
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of Charles David Young
Sent: Wednesday, October 28, 2020 5:33 AM
To: XRF
Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
?
The filter comes at a cost.? Am I reading it correctly
that it reduced the input count to %25 of the non-filtered?? Do we need to
wait 4x longer for equal counts when this is used as an exciter?? Was all
that low energy activity that is filtered out detrimental or beneficial when
the button is used to stimulate XRF in the target?
I come at this from a different perspective.? I use the
Si-PIN with an Am241 exciter to identify minerals.? In my experience the
XRF coming from the target is much stronger than the noise introduced by the
Am241, which is mounted on a shield and facing away from the detector.?
Attached is a scan of xenotime, which shows a large Y component as well as some
U and Pb.? I turned on the Am241 reference lines to show that the Np and
Au peaks are very small in comparison.? One quickly learns to recognize
and ignore them when identifying the important peaks that emanate from the
target: Ti, Mn, Fe, Ta, Th, U, Y, Zr, Nb, REEs.
?
After trying many slight thickness variations of Source
Filter components, the best result is show in the second picture.
First up is the spectra coming out of the Am exciter source with just a paper
alpha blocking filter. That alone made significant improvements at the low end
vs no alpha filter. The goal of this project is to apply a filter to the source
that will effectively remove most of the low energy component that is caused by
Np- daughter and self-XRF of elements in the button, such as Au, Ag, Fe.
Now a filter applied to the source and another Gamma Spectrum ran.
Thanks to member Dudley Emer for the design of the filter elements and
thicknesses, based on selective filtering using the K-edge X-Ray absorption
effect.
Geo
|
Wanna try this one again
Dud
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of GEOelectronics@... Sent: Wednesday, October 28, 2020 9:22 AM To: [email protected]Subject: Re: FW: [XRF] 59.5keV spectrum cleanup <div>Thickness of the layers of the most aggressive Source Filter Stack (to make it less aggressive, reduce the Cu first then the Ti) </div><div>Cu= .004" = 4mil = 100um</div><div>Ti= .001" = 1 mil = 25um</div><div>Al= .004" = 4mil = 100um</div><div><br data-mce-bogus="1"></div><div>The thinnest copper tried was 2mil, the thinnest Ti was 0.5mil, thinnest Al 4mil (Pepsi can material)<br data-mce-bogus="1"></div><div>Starting at the side the source injects the beam Cu then Ti then Al on the side facing the target, be that a sensor or a target being XRF'ed.</div><div><br data-mce-bogus="1"></div><div><div><br></div><div>The particular order of the elements is required just as we do in graded shielding of Gamma Ray probes and for the same reasons.</div></div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>All worked, it was just the matter of degree of attenuation desired at the lows and tolerable attenuation at 59.5, which is subjective.</div><div><br data-mce-bogus="1"></div><div>This combination of elements relies on the K-edge effect of selective X-Ray absorption at a particular element's K-edge energy, where an abrupt discontinuity exists, all elements having a unique energy. For the curious, yes there are other "edges" for each electron shell.</div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>My first approach was using the more subtle attenuation characteristic curve of only one element - Al (aluminum). This is still of interest and was the first step that would have lead to edge-absorption, but that was going to be in a future chapter. I like to learn by doing, and in a linear way. One step at a time usually.</div><div><br data-mce-bogus="1"></div><div>Geo</div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><br></div><div>----- Original Message -----<br>From: Dude <dfemer@...><br>To: [email protected]<br>Sent: Tue, 27 Oct 2020 19:28:26 -0400 (EDT)<br>Subject: Re: FW: [XRF] 59.5keV spectrum cleanup<br></div><div><br></div><div><style>/*<![CDATA[*/p.MsoNormal, li.MsoNormal, div.MsoNormal {<br> margin: 0.0in;<br> font-size: 12.0pt;<br> font-family: "Times New Roman" , serif;<br>}<br>a:link, span.MsoHyperlink {<br> color: blue;<br> text-decoration: underline;<br>}<br>a:visited, span.MsoHyperlinkFollowed {<br> color: purple;<br> text-decoration: underline;<br>}<br>p {<br> margin-right: 0.0in;<br> margin-left: 0.0in;<br> font-size: 12.0pt;<br> font-family: "Times New Roman" , serif;<br>}<br>p.MsoNoSpacing, li.MsoNoSpacing, div.MsoNoSpacing {<br> margin: 0.0in;<br> font-size: 16.0pt;<br> font-family: Arial , sans-serif;<br> color: black;<br>}<br>span.EmailStyle19 {<br> font-family: Arial , sans-serif;<br> color: black;<br> font-weight: normal;<br> font-style: normal;<br>}<br>*.MsoChpDefault {<br>}<br>div.Section1 {<br> page: Section1;<br>}<br>/*]]>*/</style></div><div class="Section1"><p class="MsoNormal"><span style="font-family: 'arial' , 'sans-serif'; color: black;" data-mce-style="font-family: 'arial' , 'sans-serif'; color: black;">This<br>will be interesting, What thicknesses are you running on these? </span></p><p class="MsoNormal"><span style="font-family: 'arial' , 'sans-serif'; color: black;" data-mce-style="font-family: 'arial' , 'sans-serif'; color: black;">Dud</span></p><p class="MsoNormal"><span style="font-family: 'arial' , 'sans-serif'; color: black;" data-mce-style="font-family: 'arial' , 'sans-serif'; color: black;"> </span></p><div style="border: none; border-top: solid #b5c4df 1pt; padding: 3pt 0in 0in 0in;" data-mce-style="border: none; border-top: solid #b5c4df 1pt; padding: 3pt 0in 0in 0in;"><p class="MsoNormal"><b><span style="font-size: 10pt; font-family: 'tahoma' , 'sans-serif';" data-mce-style="font-size: 10pt; font-family: 'tahoma' , 'sans-serif';">From:</span></b><span style="font-size: 10pt; font-family: 'tahoma' , 'sans-serif';" data-mce-style="font-size: 10pt; font-family: 'tahoma' , 'sans-serif';"> [email protected]<br>[mailto: [email protected]] <b>On Behalf Of </b>GEOelectronics@...<br><b>Sent:</b> Tuesday, October 27, 2020 3:00 PM<br><b>To:</b> [email protected]<br><b>Subject:</b> Re: FW: [XRF] 59.5keV spectrum cleanup</span></p></div><p class="MsoNormal"> </p><p class="MsoNormal">No but we're analyzing it's ray pattern.<br><br><br>Here's the next step, it's a redo of the Source Filter test (which I built<br>close to but not exactly to your specifications, will clean that up later in<br>the shop) with the Cu close to the source rather than the sensor side, allowing<br>the Ti and Al to attenuate the cu characteristic X-Rays that showed up on the<br>last plot.<br><br><br>More tests tomorrow, this has been real-time, making adjustments per<br>recommendations.<br><br><br>Great fun<br><br><br>PS in between these trials, the Ba-133 testing was running on another<br>instrument. Will post that tomorrow. Looks good.<br><br><br>Geo</p><div><p class="MsoNormal"><br></p><br></div></div><div style="color: white;" data-mce-style="color: white;"></div><div><br></div><div><br></div><div><br></div>
|
Charles,
Looking
at the png you sent there is something seriously wrong on the low energy below
4 keV. Send the mca file for a look as it may just be a Theremino problem. For
these low energies you’ll want to keep the Np in there, but to pull these
elements out you really need a high flux rate which the Am source isn’t doing.
Even with a tube the efficiencies are very poor and the counts are low making
it hard to quantify. However, the Al Si, P, S, Ca and K ?are absolutely
essential to determining the basic mineralogy types and every effort should be made
to verify their presence.
To
get the count times up readjust the gain to look only at the low energy range
say from 10 on down and see ff that helps pull them out. Using a tight focused
beam and close up to the target will also help concentrate the flux.
Dud
?
toggle quoted message
Show quoted text
From: [email protected]
[mailto:[email protected]] On Behalf Of Charles David Young
Sent: Wednesday, October 28, 2020 8:12 AM
To: XRF
Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
?
I agree and I did not mean to dis this exercise, even if it
turns out to be primarily academic.
When I get a chance I'll try the paper filter with a mineral
like Brannerite (UTi2O6) to see how it affects the Ti peak at 4.5keV.?
That is typically the lowest element that is essential to my application.?
Other peaks like P, K, Ca would be nice but I have learned to live without
them.? If we could somehow dig those out by an adjustment it would be
great.
?
"The filter comes at a cost.? Am I reading it
correctly that it reduced the input count to %25 of the non-filtered?? Do
we need to wait 4x longer for equal counts when this is used as an exciter?
"
All that is to be determined Charles. It well may be much
worse than that, if the low energies in the beam are what's helping to dig out
the low energy XRF signals we are looking for.
I agree about our perspective points of view too.?
You system is as ideal as can be for your main task, and
your display program is an advancement in the area of display and
identification, especially for the audience of that group. Now the photography
meets the same standard too. No one has added all those dimensions in one place
to the amateur mineral group before.? All for science' sake, and I applaud
that.
For you and others I would recommend trying a paper filter
over the exciter source, just to see.
The rest is for the X-Ray Physics and X-Ray Optics crowd. We
now have an inexpensive but powerful tool in our toolbox that wasn't there 2
days ago.
----- Original Message -----
From: Charles David Young <charlesdavidyoung@...>
To: XRF <[email protected]>
Sent: Wed, 28 Oct 2020 08:33:01 -0400 (EDT)
Subject: Re: FW: [XRF] 59.5keV spectrum cleanup
The filter comes at a cost.? Am I reading it correctly
that it reduced the input count to %25 of the non-filtered?? Do we need to
wait 4x longer for equal counts when this is used as an exciter?? Was all
that low energy activity that is filtered out detrimental or beneficial when
the button is used to stimulate XRF in the target?
I come at this from a different perspective.? I use the
Si-PIN with an Am241 exciter to identify minerals.? In my experience the
XRF coming from the target is much stronger than the noise introduced by the
Am241, which is mounted on a shield and facing away from the detector.?
Attached is a scan of xenotime, which shows a large Y component as well as some
U and Pb.? I turned on the Am241 reference lines to show that the Np and
Au peaks are very small in comparison.? One quickly learns to recognize
and ignore them when identifying the important peaks that emanate from the
target: Ti, Mn, Fe, Ta, Th, U, Y, Zr, Nb, REEs.
After trying many slight thickness variations of Source
Filter components, the best result is show in the second picture.
First up is the spectra coming out of the Am exciter source with just a paper
alpha blocking filter. That alone made significant improvements at the low end
vs no alpha filter. The goal of this project is to apply a filter to the source
that will effectively remove most of the low energy component that is caused by
Np- daughter and self-XRF of elements in the button, such as Au, Ag, Fe.
Error! Filename not specified.
Now a filter applied to the source and another Gamma Spectrum ran.
Error! Filename not specified.
Thanks to member Dudley Emer for the design of the filter elements and
thicknesses, based on selective filtering using the K-edge X-Ray absorption
effect.
Geo
?
?
|
