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 If a piece of information is incorrect, a link outdated, or the presentation choppy or unclear, the user can just click "Edit Page" at the bottom and then fix the mistake.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?]
On Saturday, December 12, 2020, 5:25 PM, GEOelectronics@... wrote:
Hi Taray, thanks for the update.
Coffee for absorption media? Why not, tests cleaner/more neutral than local soil or sand I bet!!?
Definitely "cleaner" radioactivity-wise than say mushrooms from Moscow grocery store, fireplace wood ash from Finland, or air filter from Los Angeles CA. (Cs-137)
Geo
PS Amateur Science = use what you have available and test everything!
From: "taray singh via groups.io" <sukhjez@...> To: [email protected] Sent: Friday, December 11, 2020 8:17:58 PM Subject: Re: [XRF] Xrf old faucet
Hi guys
I am about to conclude my coffee xrf analysis?
Previously scanned dirty tap water coffee ground with evidence of some heavy metals like Fe,Zn etc
The following 2 test was done on?
1 coffee beans partially ground with a rubber mallet.I do not have a??grinder.
2 Coffee ground??from my hospital Nescafe Milano coffee maker
The coffee beans( Vietnam) appears clean with no heavy metals?
The coffee ground results show??no evidence of heavy metals in my hospital drinking water?
But it does show a Chromium peak .
This Cr peak may be coming from any chromium plated heating elements used in the coffee maker.
My home tap water results done earlier are verified .
Final note coffee ground can be used as an absorbent material for xrf analysis of contamination??from heavy metals?
The principle behind this is a negative charge on the molecules attracting cations?
Pics are for?
Partially ground coffee??beans?
Used??clean coffee ground
Since these samples are unpressed ,there will be some sampling error
Taray
On Tuesday, December 8, 2020, 8:17 PM, GEOelectronics@... <GEOelectronics@...> wrote:
This is an interesting thread Taray, thanks, we will watch it grow.
Geo
From: "taray singh via groups.io" <sukhjez@...> To: [email protected] Sent: Monday, December 7, 2020 6:48:31 PM Subject: Re: [XRF] Xrf old faucet
Forgot this..
On Tuesday, December 8, 2020, 8:40 AM, taray singh via groups.io <sukhjez@...> wrote:
I collected first flush from unused faucets and a reddish brown sludge was subsequently??added??to used coffee ground .?
Soaked overnight?
Excess water drained out and coffee put to dry in the sun
Subsequently repacked in thin kitchen plastic and scanned overnight?
Xrf findings show Fe,Ni ,Zn and lead?
A test of shorter duration??of clean used coffee show weaker peaks??somewhat similar.
Putting together the old faucet structure and this finding makes me arrive to a certain conclusion?
Zinc faucets a potent corrosive agents
The stagnant water in the faucet and??the proximal plumbing system is accounting for a build up of heavy metals?
If left alone it will eventually cause total blockage like what happened??to this faucet?
This coffee ground is all also a reflection??of the state of the water used at the primary source??and the actual brewing process where heating elements leached
metals into the coffee
This coffee ground came from hospital lounge?
Apparently all drinking water there is prefiltered
So far nobody I contacted including??the technicians could tell me the nature of the heating elements used in my??coffee maker?
Ni ,Cr,Al or steel are common heating coils.
The coffee beans have some natural elements present excluding any poor irrigation??system at the plantations.
I have to do test on clean coffee beans and a another for the used coffee ground to get a clear picture of my faucet findings.
But putting all the pieces together does suggest my tap water water contain measurable heavy??metals?
Pics are coffee ground residue??/clean coffee 4096 mca?
I think I will take a coffee break??for now
Taray
On Monday, November 16, 2020, 2:22 AM, GEOelectronics@... <GEOelectronics@...> wrote:
First being shown is Taray's "Tap sediment end.mca) loaded into live_data_2 and showing as? solid red peaks
with the "Tap brass.mca" loaded in live_data_1 with its peaks showing as black outlines. If the user wished to see only one set of peaks, the other ones would have been set to H for HIDE instead of left with no letter in the front. If set up that way, you can animate them back and forth with keystrokes. Sometimes overlaying the peaks is too busy to be effective.
I've highlighted different peaks, especially the Pb Ka1. It will be clearer in the second picture what a big difference there is at 10.55kev between the scans. To me this would definitely raise a red flag for Pb but at this stage is not definite enough to call it 100%. Further testing would be merited and could swing it one way or the other.
All colors are set by the user as is their intensity (# of pixels)
Notice at the top of the display it is showing the name of the active .mca file. When we change the other file to being active instead, this will change to that file name.
Now the same two scans, but switched with the outline becoming solid red and vise versa.
To me the 10.55keV difference is much clearer in this setting. Close but about half a channel off Pb
.
However below see how we can expand down to 1 keV full width (less is possible, and this scan was taken with only 2048 channels, we can do up to 8k channels for even better resolution but longer scan time). 1 keV = 1000 electron-volts. Look how many individual peaks can be inside a single keV.
After some 34 hours have past, some more probable Eu-152 peaks starting to show (highlighted by red arrows) Normally a peak of <10 counts can be ignored. Put it off to random summation peak, noise etc. Sometimes, when coupled with more solid evidence they can still be helpful.?
Case in point is in the range of energies above that which this particular sensor is linear in its response curve (above 100 keV). Pointed out are tow areas of peaks that look like a saw tooth shape, with a sharp decline on the right side. I've learned to pay attention to that pattern, even though it is never picked up by software driven Peak-Search.?
Eu has many peaks over a wide range of energies. Two of the most intense ones that fall into our measurement range with this detector are 244.7keV @ 7.5% intensity and 244.28keV @ 26.50% intensity.
The right edge of the two saw-tooth shapes is exactly at those energies. Over time they will no doubt develop further. For now I use them as tentative additional confirmation of a better "fit" of this pattern to the overall decay scheme unique to Eu-152. Geo
Not even close, Randall, once the electronics are as good as they can be (did you mention coaxial cable capacitance?), the tube itself, or rather the gas inside it opens a whole new con-of-worms. Imagine the excess contribution of heavy noble gasses like Argon or Krypton or Xenon muddying the XRF waters at the atomic level. Internal XRF peaks, selective X-Ray absorption etc.
Beryllium windowed Proportional Counters were the only game in town at one time, kudos to those patient enough to work with them.
PS they do make for excellent XRF targets, for element XRF right through the Be window. Probably the most practical way to add Krypton and Xenon to your element collection.
----- Original Message ----- From: "Randall Buck" <rbuck@...> To: [email protected] Cc: [email protected] Sent: Friday, December 11, 2020 10:44:30 PM Subject: Re: [XRF] Proportional Counters and Preamps
Hi,
There seem to be quite a few interrelated electrical parameters, physical properties (of the x-ray/PC chamber) and design compromises involved.
I don't have it all organized into one simple view.
1) Because the PC chamber has an intrinsically low capacitance, the output pulse should have a very fast rise time, hence the need for an op amp with a high but not excessive slew rate.
2) Since we are interested in the accurate reproduction of the pulse from the chamber (but at a higher amplitude for further processing - ultimately by the MCA), the settling time spec is also critical. Settling time for the op amp output peak to reach the amplified version of the peak input pulse from the PC chamber. Settling time is usually specified to within some percent of the final value, which is only obtained after a relatively long delay; typically, to 0.1% of the ultimate output peak. A more accurate pulse amplification process would result from the same settling time to say 0.01%. For us DIY'rs, the actual settling time is not too critical since we can always slow down the count rate via x-ray attenuation and just wait longer for the result. So we want a precision op amp with a slew rate that exceeds the rise time of the PC output, settles to an accurate amplified pulse magnitude then back to zero within a reasonable amount of time to make room for the next pulse.
3) For MCA applications, the repeatability of the PC chamber output pulse height for a given x-ray energy input is important since it controls the fundamental energy resolution of the of the final result. I.e., begin by assuming a monoenergenic x-ray input to the PC. If all the output pulse heights from the PC are identical then a perfect condition exists and we only need to amplify those PC pulses, and route them to an MCA. The result would be an ideal vertical line of zero FWHM, i.e., perfect energy resolution. Of course, that happy world is only a fantasy degraded by noise and nonlinearities throughout the system,beginning with the PC, all the way to the MCA itself.
4) Noise: since we are connecting the op amp as a charge amp, its transfer function will be measured in say, 2 nC/V (two nanocoulombs of input charge will result in an output pulse with a peak magnitude of one volt). So 550 electrons, FWHM means that a charge equivalent to 550 electrons (= 550 x 1.6x10E-19 Coul per electron = 8.8 x 10E-8 nano coul = 0.4 nV uncertainty in the amplified pulse height) -pretty good. That translates to a 0.4 nV uncertainty in the left to right position on the MCA display (low pulse heights on the left,high pulse heights on the right.) Too good to waste on a PC. The 0.5 keV noise spec must be at some particular amplification in order to compare with this example.
5) PC capacitance: A higher terminal capacitance will result in more integration of the output pulse (squished down in peak value and spread out in time) This makes accurate peak pulse height measurement more difficult, which results in more peak height uncertainty and that translates to a larger FWHM.
which brings me to burnout
Randall
----- Original Message ----- From: Soren <justinhuber@...> To: [email protected] Sent: Fri, 11 Dec 2020 17:07:54 -0800 (PST) Subject: Re: [XRF] Proportional Counters and Preamps
Dear Randall,
Yes. You're right about the Hamamatsu - it is for a SiPIN. I have a vague memory that I saw some articles about the A-250 being deployed on satellites and I seem to remember the detectors being proportional counters - but I could be wrong. Looking at the data sheet for the A-250, it mentions proportional counters as a possible detector.
To a certain degree this is more of an academic exercise - to understand the underlying circuit theory of these "state of the art' preamps. I have a Amptek SiPIN on its way in the mail right now. But I figure that since I have the proportional counter, why not try to get it working as I think it will be more sensitive in the higher energy regions than the SiPIN.
It's a little hard to compare noise specs as the measures seem to be different. The Hamamatsu is listed as having a "550 Electron/FWHM noise characteristic." The A-150 instead provides a chart indicating that with certain front end FETs, such as the 2SK152 (of which I just received 5 in the mail), at 2pF capacitance the noise is about .5kev FWHM. I'm not sure if those are just different terms for the same thing. The patent claims to have measured "equivalent noise charge of less than 20 electrons r.m.s." But as I'm a bit new to this, I'm not sure if these measures are all the same.
Earlier you mentioned
Now to compare the op amp specs with the Ortec 142PC
There may also be other, higher performance alternatives. With such a low capacitance in the Porp Chamber, stability, slew rate and settling time (at a good accuracy level) will be important characteristics if the goal is energy discrimination, not just detection.
Comparing the gain bandwidth product of a couple options, we get;
* AD823:??3 dB bandwidth of 16 MHz, G = +1 * Amptek A-250:?300 MHz with 2N4416 FET
Having just learned what slew rate and gain bandwidth product are about 4 days ago, I'm not sure that I'm equipped (read: too lazy to do the math) to compare other characteristics.
But I know that the are much better op amps out there such as the AD829, which appears to be what Amptek is using in their PA-230 preamp. This has a 230V/?s slew rate and a much better settling time than the AD823. The AD829 and the AD823 are about the same price ¡Ö$7 but you'd need two of the AD829s since its only a single op amp chip.
I imagine that slew rate is more important as the count-rate goes up. And gain bandwidth product is more important and one needs to amplify smaller and smaller signals? Is that right or have I gotten my wires crossed?
Then there is the ADA4530-1 which has an input bias of 20fA. But that might be for different applications altogether.
I know with SiPIN low capacitance is a good thing (hence the use of high reverse breakdown voltage PINs). What are the issues with a low capacitance proportional counter?
Coffee for absorption media? Why not, tests cleaner/more neutral than local soil or sand I bet!!?
Definitely "cleaner" radioactivity-wise than say mushrooms from Moscow grocery store, fireplace wood ash from Finland, or air filter from Los Angeles CA. (Cs-137)
Geo
PS Amateur Science = use what you have available and test everything!
From: "taray singh via groups.io" <sukhjez@...> To: [email protected] Sent: Friday, December 11, 2020 8:17:58 PM Subject: Re: [XRF] Xrf old faucet
Hi guys
I am about to conclude my coffee xrf analysis?
Previously scanned dirty tap water coffee ground with evidence of some heavy metals like Fe,Zn etc
The following 2 test was done on?
1 coffee beans partially ground with a rubber mallet.I do not have a??grinder.
2 Coffee ground??from my hospital Nescafe Milano coffee maker
The coffee beans( Vietnam) appears clean with no heavy metals?
The coffee ground results show??no evidence of heavy metals in my hospital drinking water?
But it does show a Chromium peak .
This Cr peak may be coming from any chromium plated heating elements used in the coffee maker.
My home tap water results done earlier are verified .
Final note coffee ground can be used as an absorbent material for xrf analysis of contamination??from heavy metals?
The principle behind this is a negative charge on the molecules attracting cations?
Pics are for?
Partially ground coffee??beans?
Used??clean coffee ground
Since these samples are unpressed ,there will be some sampling error
Taray
On Tuesday, December 8, 2020, 8:17 PM, GEOelectronics@... <GEOelectronics@...> wrote:
This is an interesting thread Taray, thanks, we will watch it grow.
Geo
From: "taray singh via groups.io" <sukhjez@...> To: [email protected] Sent: Monday, December 7, 2020 6:48:31 PM Subject: Re: [XRF] Xrf old faucet
Forgot this..
On Tuesday, December 8, 2020, 8:40 AM, taray singh via groups.io <sukhjez@...> wrote:
I collected first flush from unused faucets and a reddish brown sludge was subsequently??added??to used coffee ground .?
Soaked overnight?
Excess water drained out and coffee put to dry in the sun
Subsequently repacked in thin kitchen plastic and scanned overnight?
Xrf findings show Fe,Ni ,Zn and lead?
A test of shorter duration??of clean used coffee show weaker peaks??somewhat similar.
Putting together the old faucet structure and this finding makes me arrive to a certain conclusion?
Zinc faucets a potent corrosive agents
The stagnant water in the faucet and??the proximal plumbing system is accounting for a build up of heavy metals?
If left alone it will eventually cause total blockage like what happened??to this faucet?
This coffee ground is all also a reflection??of the state of the water used at the primary source??and the actual brewing process where heating elements leached
metals into the coffee
This coffee ground came from hospital lounge?
Apparently all drinking water there is prefiltered
So far nobody I contacted including??the technicians could tell me the nature of the heating elements used in my??coffee maker?
Ni ,Cr,Al or steel are common heating coils.
The coffee beans have some natural elements present excluding any poor irrigation??system at the plantations.
I have to do test on clean coffee beans and a another for the used coffee ground to get a clear picture of my faucet findings.
But putting all the pieces together does suggest my tap water water contain measurable heavy??metals?
Pics are coffee ground residue??/clean coffee 4096 mca?
I think I will take a coffee break??for now
Taray
On Monday, November 16, 2020, 2:22 AM, GEOelectronics@... <GEOelectronics@...> wrote:
First being shown is Taray's "Tap sediment end.mca) loaded into live_data_2 and showing as? solid red peaks
with the "Tap brass.mca" loaded in live_data_1 with its peaks showing as black outlines. If the user wished to see only one set of peaks, the other ones would have been set to H for HIDE instead of left with no letter in the front. If set up that way, you can animate them back and forth with keystrokes. Sometimes overlaying the peaks is too busy to be effective.
I've highlighted different peaks, especially the Pb Ka1. It will be clearer in the second picture what a big difference there is at 10.55kev between the scans. To me this would definitely raise a red flag for Pb but at this stage is not definite enough to call it 100%. Further testing would be merited and could swing it one way or the other.
All colors are set by the user as is their intensity (# of pixels)
Notice at the top of the display it is showing the name of the active .mca file. When we change the other file to being active instead, this will change to that file name.
Now the same two scans, but switched with the outline becoming solid red and vise versa.
To me the 10.55keV difference is much clearer in this setting. Close but about half a channel off Pb
.
However below see how we can expand down to 1 keV full width (less is possible, and this scan was taken with only 2048 channels, we can do up to 8k channels for even better resolution but longer scan time). 1 keV = 1000 electron-volts. Look how many individual peaks can be inside a single keV.
There seem to be quite a few interrelated electrical parameters, physical properties (of the x-ray/PC chamber) and design compromises involved.
I don't have it all organized into one simple view.
1) Because the PC chamber has an intrinsically low capacitance, the output pulse should have a very fast rise time, hence the need for an op amp with a high but not excessive slew rate.
2) Since we are interested in the accurate reproduction of the pulse from the chamber (but at a higher amplitude for further processing - ultimately by the MCA), the settling time spec is also critical. Settling time for the op amp output peak to reach the amplified version of the peak input pulse from the PC chamber. Settling time is usually specified to within some percent of the final value, which is only obtained after a relatively long delay; typically, to 0.1% of the ultimate output peak. A more accurate pulse amplification process would result from the same settling time to say 0.01%. For us DIY'rs, the actual settling time is not too critical since we can always slow down the count rate via x-ray attenuation and just wait longer for the result. So we want a precision op amp with a slew rate that exceeds the rise time of the PC output, settles to an accurate amplified pulse magnitude then back to zero within a reasonable amount of time to make room for the next pulse.
3) For MCA applications, the repeatability of the PC chamber output pulse height for a given x-ray energy input is important since it controls the fundamental energy resolution of the of the final result. I.e., begin by assuming a monoenergenic x-ray input to the PC. If all the output pulse heights from the PC are identical then a perfect condition exists and we only need to amplify those PC pulses, and route them to an MCA. The result would be an ideal vertical line of zero FWHM, i.e., perfect energy resolution. Of course, that happy world is only a fantasy degraded by noise and nonlinearities throughout the system,beginning with the PC, all the way to the MCA itself.
4) Noise: since we are connecting the op amp as a charge amp, its transfer function will be measured in say, 2 nC/V (two nanocoulombs of input charge will result in an output pulse with a peak magnitude of one volt). So 550 electrons, FWHM means that a charge equivalent to 550 electrons (= 550 x 1.6x10E-19 Coul per electron = 8.8 x 10E-8 nano coul = 0.4 nV uncertainty in the amplified pulse height) -pretty good. That translates to a 0.4 nV uncertainty in the left to right position on the MCA display (low pulse heights on the left,high pulse heights on the right.) Too good to waste on a PC. The 0.5 keV noise spec must be at some particular amplification in order to compare with this example.
5) PC capacitance: A higher terminal capacitance will result in more integration of the output pulse (squished down in peak value and spread out in time) This makes accurate peak pulse height measurement more difficult, which results in more peak height uncertainty and that translates to a larger FWHM.
----- Original Message ----- From: Soren <justinhuber@...> To: [email protected] Sent: Fri, 11 Dec 2020 17:07:54 -0800 (PST) Subject: Re: [XRF] Proportional Counters and Preamps
Dear Randall,
Yes. You're right about the Hamamatsu - it is for a SiPIN. I have a vague memory that I saw some articles about the A-250 being deployed on satellites and I seem to remember the detectors being proportional counters - but I could be wrong. Looking at the data sheet for the A-250, it mentions proportional counters as a possible detector.
To a certain degree this is more of an academic exercise - to understand the underlying circuit theory of these "state of the art' preamps. I have a Amptek SiPIN on its way in the mail right now. But I figure that since I have the proportional counter, why not try to get it working as I think it will be more sensitive in the higher energy regions than the SiPIN.
It's a little hard to compare noise specs as the measures seem to be different. The Hamamatsu is listed as having a "550 Electron/FWHM noise characteristic." The A-150 instead provides a chart indicating that with certain front end FETs, such as the 2SK152 (of which I just received 5 in the mail), at 2pF capacitance the noise is about .5kev FWHM. I'm not sure if those are just different terms for the same thing. The patent claims to have measured "equivalent noise charge of less than 20 electrons r.m.s." But as I'm a bit new to this, I'm not sure if these measures are all the same.
Earlier you mentioned
Now to compare the op amp specs with the Ortec 142PC
There may also be other, higher performance alternatives. With such a low capacitance in the Porp Chamber, stability, slew rate and settling time (at a good accuracy level) will be important characteristics if the goal is energy discrimination, not just detection.
Comparing the gain bandwidth product of a couple options, we get;
* AD823:??3 dB bandwidth of 16 MHz, G = +1 * Amptek A-250:?300 MHz with 2N4416 FET
Having just learned what slew rate and gain bandwidth product are about 4 days ago, I'm not sure that I'm equipped (read: too lazy to do the math) to compare other characteristics.
But I know that the are much better op amps out there such as the AD829, which appears to be what Amptek is using in their PA-230 preamp. This has a 230V/?s slew rate and a much better settling time than the AD823. The AD829 and the AD823 are about the same price ¡Ö$7 but you'd need two of the AD829s since its only a single op amp chip.
I imagine that slew rate is more important as the count-rate goes up. And gain bandwidth product is more important and one needs to amplify smaller and smaller signals? Is that right or have I gotten my wires crossed?
Then there is the ADA4530-1 which has an input bias of 20fA. But that might be for different applications altogether.
I know with SiPIN low capacitance is a good thing (hence the use of high reverse breakdown voltage PINs). What are the issues with a low capacitance proportional counter?
On Tuesday, December 8, 2020, 8:17 PM, GEOelectronics@... <GEOelectronics@...> wrote:
This is an interesting thread Taray, thanks, we will watch it grow.
Geo
From: "taray singh via groups.io" <sukhjez@...> To: [email protected] Sent: Monday, December 7, 2020 6:48:31 PM Subject: Re: [XRF] Xrf old faucet
Forgot this..
On Tuesday, December 8, 2020, 8:40 AM, taray singh via groups.io <sukhjez@...> wrote:
I collected first flush from unused faucets and a reddish brown sludge was subsequently??added??to used coffee ground .?
Soaked overnight?
Excess water drained out and coffee put to dry in the sun
Subsequently repacked in thin kitchen plastic and scanned overnight?
Xrf findings show Fe,Ni ,Zn and lead?
A test of shorter duration??of clean used coffee show weaker peaks??somewhat similar.
Putting together the old faucet structure and this finding makes me arrive to a certain conclusion?
Zinc faucets a potent corrosive agents
The stagnant water in the faucet and??the proximal plumbing system is accounting for a build up of heavy metals?
If left alone it will eventually cause total blockage like what happened??to this faucet?
This coffee ground is all also a reflection??of the state of the water used at the primary source??and the actual brewing process where heating elements leached
metals into the coffee
This coffee ground came from hospital lounge?
Apparently all drinking water there is prefiltered
So far nobody I contacted including??the technicians could tell me the nature of the heating elements used in my??coffee maker?
Ni ,Cr,Al or steel are common heating coils.
The coffee beans have some natural elements present excluding any poor irrigation??system at the plantations.
I have to do test on clean coffee beans and a another for the used coffee ground to get a clear picture of my faucet findings.
But putting all the pieces together does suggest my tap water water contain measurable heavy??metals?
Pics are coffee ground residue??/clean coffee 4096 mca?
I think I will take a coffee break??for now
Taray
On Monday, November 16, 2020, 2:22 AM, GEOelectronics@... <GEOelectronics@...> wrote:
First being shown is Taray's "Tap sediment end.mca) loaded into live_data_2 and showing as? solid red peaks
with the "Tap brass.mca" loaded in live_data_1 with its peaks showing as black outlines. If the user wished to see only one set of peaks, the other ones would have been set to H for HIDE instead of left with no letter in the front. If set up that way, you can animate them back and forth with keystrokes. Sometimes overlaying the peaks is too busy to be effective.
I've highlighted different peaks, especially the Pb Ka1. It will be clearer in the second picture what a big difference there is at 10.55kev between the scans. To me this would definitely raise a red flag for Pb but at this stage is not definite enough to call it 100%. Further testing would be merited and could swing it one way or the other.
All colors are set by the user as is their intensity (# of pixels)
Notice at the top of the display it is showing the name of the active .mca file. When we change the other file to being active instead, this will change to that file name.
Now the same two scans, but switched with the outline becoming solid red and vise versa.
To me the 10.55keV difference is much clearer in this setting. Close but about half a channel off Pb
.
However below see how we can expand down to 1 keV full width (less is possible, and this scan was taken with only 2048 channels, we can do up to 8k channels for even better resolution but longer scan time). 1 keV = 1000 electron-volts. Look how many individual peaks can be inside a single keV.
Yes. You're right about the Hamamatsu - it is for a SiPIN. I have a vague memory that I saw some articles about the A-250 being deployed on satellites and I seem to remember the detectors being proportional counters - but I could be wrong. Looking at the data sheet for the A-250, it mentions proportional counters as a possible detector.
To a certain degree this is more of an academic exercise - to understand the underlying circuit theory of these "state of the art' preamps. I have a Amptek SiPIN on its way in the mail right now. But I figure that since I have the proportional counter, why not try to get it working as I think it will be more sensitive in the higher energy regions than the SiPIN.?
It's a little hard to compare noise specs as the measures seem to be different. The Hamamatsu is listed as having a "550 Electron/FWHM noise characteristic." The A-150 instead provides a chart indicating that with certain front end FETs, such as the 2SK152 (of which I just received 5 in the mail), at 2pF capacitance the noise is about .5kev FWHM. I'm not sure if those are just different terms for the same thing. The patent claims to have measured "equivalent noise charge of less than 20 electrons r.m.s." But as I'm a bit new to this, I'm not sure if these measures are all the same.
Earlier you mentioned
Now to compare the op amp specs with the Ortec 142PC
There may also be other, higher performance alternatives. With such a low capacitance in the Porp Chamber, stability, slew rate and settling time (at a good accuracy level) will be important characteristics if the goal is energy discrimination, not just detection.
Comparing the gain bandwidth product of a couple options, we get;
AD823:??3 dB bandwidth of 16 MHz, G = +1
Amptek A-250:?300 MHz with 2N4416 FET
Having just learned what slew rate and gain bandwidth product are about 4 days ago, I'm not sure that I'm equipped (read: too lazy to do the math) to compare other characteristics.
But I know that the are much better op amps out there such as the AD829, which appears to be what Amptek is using in their PA-230 preamp. This has a 230V/?s slew rate and a much better settling time than the AD823. The AD829 and the AD823 are about the same price ¡Ö$7 but you'd need two of the AD829s since its only a single op amp chip.
A quick DigiKey search yields some other options;
LTC6253 - $7 - 280V/?s - 720MHz
OPA2690 - $6 - 1800V/?s - 300MHz
LMH6626 - $6.5 - 360V/?s - 1.3GHz
THS3062 - $13.5 - 7000V/?S - 2.2GHz
I imagine that slew rate is more important as the count-rate goes up. And gain bandwidth product is more important and one needs to amplify smaller and smaller signals? Is that right or have I gotten my wires crossed?
Then there is the ADA4530-1 which has an input bias of 20fA. But that might be for different applications altogether.
I know with SiPIN low capacitance is a good thing (hence the use of high reverse breakdown voltage PINs). What are the issues with a low capacitance proportional counter?
The patent is interesting but the other two are for Ortec 142 A/B/C type applications, like Geo and others are using, solid state PIN and other detectors.
----- Original Message ----- From: Soren <justinhuber@...> To: [email protected] Sent: Thu, 10 Dec 2020 18:31:12 -0800 (PST) Subject: Re: [XRF] Proportional Counters and Preamps
I found an interesting patents that eliminates the noise producing feedback resistor and also does some magic to avoid the need of a reset circuit to prevent saturation. It's pretty straightforward and I never mind a little through hole perfboard soldering so I'll probably give it a go - why not for $10-20. The patent is expired and it claims (if I read it correctly regarding the rms electron noise) to be better than many commercial products including the Amptek A-250. I'll attach it below.
I've been studying some grainy pictures of the Hamamatsu H4083 to see if I can reverse engineer it since the part count is very low. But some of the SMD markings are a bit unclear (ok, they all are) and it looks like they may be pulling of some sort of trick on the board itself of creating capacitance with the traces themselves - there are all sorts of strange squares visible in addition to the smd parts themselves. If anyone has any high res photos of the innards of an Amptek A-250 or a Hamamatsu H4038, it would be fun to reverse engineer and see how the commercial outfits do this. I'm rather fascinated by these little hybrid modules.
As a little side note, from studying some eBay pictures of the Amptek XCR-210 it looks like they use a XC6103 (SMD Marking: 21V gives the specs) as a voltage detector to trigger the reset pulse. I think the PA-230 uses the same thing. If you look on eBay you'll see pictures and it is U3. But a lot of the part numbers and traces are blurred. I don't necessary want to copy their design, but it is still interesting to see how it is implemented.
Gamma Spectrum scan only-
no exciter-Desert sand. Excavated by ants outside the fenced area, see report
by Rob Hermes etal.
Small sample, having been picked through and "discarded" - just sand
after all- but is it?
A unique view of neutron activation (alone), 75 years later. No noticeable
fission products, very slight Am contamination (sand has not been washed or
sieved yet? just all the spheres, dumbells, any other co-mingled debris
carefully removed with tweezers under microscope for a different study).
.mca and the custom .lib attached- to use library, change the postscript
".txt" to ".lib" instead. For some reason Groips.io won't
forward a post with a .lib file attached!?
Gamma Spectrum scan only- no exciter-Desert sand. Excavated by ants outside the fenced area, see report by Rob Hermes etal.
Small sample, having been picked through and "discarded" - just sand after all- but is it?
A unique view of neutron activation (alone), 75 years later. No noticeable fission products, very slight Am contamination (sand has not been washed or sieved yet? just all the spheres, dumbells, any other co-mingled debris carefully removed with tweezers under microscope for a different study).
.mca and the custom .lib attached- to use library, change the postscript ".txt" to ".lib" instead. For some reason Groips.io won't forward a post with a .lib file attached!?
I found an interesting patents that eliminates the noise producing feedback resistor and also does some magic to avoid the need of a reset circuit to prevent saturation. It's pretty straightforward and I never mind a little through hole perfboard soldering so I'll probably give it a go - why not for $10-20. The patent is expired and it claims (if I read it correctly regarding the rms electron noise) to be better than many commercial products including the Amptek A-250. I'll attach it below.
I've been studying some grainy pictures of the Hamamatsu H4083 to see if I can reverse engineer it since the part count is very low. But some of the SMD markings are a bit unclear (ok, they all are) and it looks like they may be pulling of some sort of trick on the board itself of creating capacitance with the traces themselves - there are all sorts of strange squares visible in addition to the smd parts themselves. If anyone has any high res photos of the innards of an Amptek A-250 or a Hamamatsu H4038, it would be fun to reverse engineer and see how the commercial outfits do this. I'm rather fascinated by these little hybrid modules.
As a little side note, from studying some eBay pictures of the Amptek XCR-210 it looks like they use a XC6103 (SMD Marking: 21V gives the specs) as a voltage detector to trigger the reset pulse. I think the PA-230 uses the same thing. If you look on eBay you'll see pictures and it is U3. But a lot of the part numbers and traces are blurred. I don't necessary want to copy their design, but it is still interesting to see how it is implemented.
Now to compare the op amp specs with the Ortec 142PC
There may also be other, higher performance alternatives. With such a low capacitance in the Porp Chamber, stability, slew rate and settling time (at a good accuracy level) will be important characteristics if the goal is energy discrimination,not just detection.
----- Original Message ----- From: Soren <justinhuber@...> To: [email protected] Sent: Wed, 09 Dec 2020 21:54:08 -0800 (PST) Subject: Re: [XRF] Proportional Counters and Preamps
Randall,
Thanks.
Someone alerted me to the fact that Spectrum Techniques makes a preamp designed for Proportional Counters. There is not reference to it on their website, but the product manual with schematic is still there on the server:
They are using an AD823 - Analog Devices Dual FET OpAmp. So that seems to be the solution.
The amount of Pu-240 in that era of devices was about 2.5% with
Pu-241 of about 0.05%. If you look at the Green Top CdTe 86Ksec mca again the
Pu 240 appears at 45.24 next to the Pu 239 at 51.62 keV. Additional Pu-240 is
generated by multiple neutron capture from U-238 and Pu-239. In the same
fashion Pu-241 is also generated by multiple neutron capture from U-238 and
Pu-239.? The U x-rays seen are from all of the Pu decay not just Pu-239.
The Am-241 is due to in-growth from both the Pu-241 and from the original
Pu-241 impurity. Even from a Pu safety shot where there was no fission involved
the Am is readily detectable and increases with age.
If the jet hypothesis is correct then there I would suspect there
be other cable locations showing the red trinitite, but only that one location
was reported and that was where the power lines came in. Perhaps a transformer
got vaporized in that area?.
The Eu activation and concentration would depend on the slant
angle distance and the amount mixed when pulled up, melted in place or
splattered. So I¡¯d say it¡¯d be mechanism and ?location dependent.
Dud
?
OK here's the reference RE: "supergrade Pu-239"? pretty current
pubs, loaned to me by the author-
"Distribution and behavior of some radionuclides
associated?with the Trinity nuclear test"
Jeremy J. Bellucci ? Christine Wallace ? Elizabeth C. Koeman ?
Antonio Simonetti ? Peter C. Burns ? Jeremy Kieser ?
Eli Port ? Terri Walczak:
The device, Gadget,?was an implosion-type design with a
¡®¡®super-grade¡¯¡¯
239Pu core produced at the Hanford site (240Pu/239Pu =
0.0128¨C0.016 mol/mole, [1, 2]).
Acknowledgments The authors thank the separations and radiochemistry
research team at Pacific Northwest National Laboratory
and Dr. Ed Stech in the Department of Physics at the University of
Notre Dame for thoughtful discussions. This research work was
funded by DOE/NNSA grant PDP11-40/DE-NA0001112.
References
1. Fahey AJ, Zeissler CJ, Newbury DE, Davis J, Lindstrom RM
(2010) Postdetonation nuclear debris for attribution. Proc Nat
Here's another reference mentioning super-grade Pu-239. Of course that's what went in to the device. The ratio of Pu isotopes left in Trinitite is another matter entirely due to neutron absorption.
Quote: "The Trinity device
was an implosion-type device organized in several concentric shells and containing about
6 kg of supergrade Pu fuel (~99.1% of 239Pu, ~0.9% of 240Pu and trace amounts of 241Pu)."
Attributed to and thanks for the loan by Elisabeth Koeman:
DETERMINATION OF PU ISOTOPE SYSTEMATICS OF TRINITITE POSTDETONATION MATERIAL
MANA, Sara
1
, SIMONETTI, Antonio
2
, WALLACE, Christine
2
, KOEMAN, Elizabeth
C.
2
, DONOHUE, Patrick
2
, and BURNS, Peter C.
1
(1) Department of Civil and Environmental Engineering and Earth Sciences, University
of Notre Dame, 301 Stinson Remick Hall, Notre Dame, IN 46556
manasara.geo@...
(2) Department of Civil and Environmental Engineering and Earth Sciences, University
of Notre Dame, 156 Fitzpatrick Hall, Notre Dame, IN 46556
From: GEOelectronics@... To: [email protected] Sent: Thursday, December 10, 2020 3:35:45 AM Subject: Re: [XRF] Trinitite
On Wed, Dec 9, 2020 at 12:38 PM, Dude wrote:
Geo,
The amount of Pu-240 in that era of devices was about 2.5% with Pu-241 of about 0.05%. If you look at the Green Top CdTe 86Ksec mca again the Pu 240 appears at 45.24 next to the Pu 239 at 51.62 keV. Additional Pu-240 is generated by multiple neutron capture from U-238 and Pu-239. In the same fashion Pu-241 is also generated by multiple neutron capture from U-238 and Pu-239.? The U x-rays seen are from all of the Pu decay not just Pu-239. The Am-241 is due to in-growth from both the Pu-241 and from the original Pu-241 impurity. Even from a Pu safety shot where there was no fission involved the Am is readily detectable and increases with age.
If the jet hypothesis is correct then there I would suspect there be other cable locations showing the red trinitite, but only that one location was reported and that was where the power lines came in. Perhaps a transformer got vaporized in that area?.
The Eu activation and concentration would depend on the slant angle distance and the amount mixed when pulled up, melted in place or splattered. So I¡¯d say it¡¯d be mechanism and ?location dependent.
Dud
?
OK here's the reference RE: "supergrade Pu-239"? pretty current pubs, loaned to me by the author-
"Distribution and behavior of some radionuclides associated?with the Trinity nuclear test"
Jeremy J. Bellucci ? Christine Wallace ? Elizabeth C. Koeman ?
Antonio Simonetti ? Peter C. Burns ? Jeremy Kieser ?
Eli Port ? Terri Walczak:
The device, Gadget,?was an implosion-type design with a ¡®¡®super-grade¡¯¡¯
239Pu core produced at the Hanford site (240Pu/239Pu =
0.0128¨C0.016 mol/mole, [1, 2]).
Acknowledgments The authors thank the separations and radiochemistry
research team at Pacific Northwest National Laboratory
and Dr. Ed Stech in the Department of Physics at the University of
Notre Dame for thoughtful discussions. This research work was
funded by DOE/NNSA grant PDP11-40/DE-NA0001112.
References
1. Fahey AJ, Zeissler CJ, Newbury DE, Davis J, Lindstrom RM
(2010) Postdetonation nuclear debris for attribution. Proc Nat
The amount of Pu-240 in that era of devices was about 2.5% with Pu-241 of about 0.05%. If you look at the Green Top CdTe 86Ksec mca again the Pu 240 appears at 45.24 next to the Pu 239 at 51.62 keV. Additional Pu-240 is generated by multiple neutron capture from U-238 and Pu-239. In the same fashion Pu-241 is also generated by multiple neutron capture from U-238 and Pu-239.? The U x-rays seen are from all of the Pu decay not just Pu-239. The Am-241 is due to in-growth from both the Pu-241 and from the original Pu-241 impurity. Even from a Pu safety shot where there was no fission involved the Am is readily detectable and increases with age.
If the jet hypothesis is correct then there I would suspect there be other cable locations showing the red trinitite, but only that one location was reported and that was where the power lines came in. Perhaps a transformer got vaporized in that area?.
The Eu activation and concentration would depend on the slant angle distance and the amount mixed when pulled up, melted in place or splattered. So I¡¯d say it¡¯d be mechanism and ?location dependent.
Dud
?
OK here's the reference RE: "supergrade Pu-239"? pretty current pubs, loaned to me by the author-
"Distribution and behavior of some radionuclides associated?with the Trinity nuclear test"
Jeremy J. Bellucci ? Christine Wallace ? Elizabeth C. Koeman ?
Antonio Simonetti ? Peter C. Burns ? Jeremy Kieser ?
Eli Port ? Terri Walczak:
The device, Gadget,?was an implosion-type design with a ¡®¡®super-grade¡¯¡¯
239Pu core produced at the Hanford site (240Pu/239Pu =
0.0128¨C0.016 mol/mole, [1, 2]).
Acknowledgments The authors thank the separations and radiochemistry
research team at Pacific Northwest National Laboratory
and Dr. Ed Stech in the Department of Physics at the University of
Notre Dame for thoughtful discussions. This research work was
funded by DOE/NNSA grant PDP11-40/DE-NA0001112.
References
1. Fahey AJ, Zeissler CJ, Newbury DE, Davis J, Lindstrom RM
(2010) Postdetonation nuclear debris for attribution. Proc Nat
Someone alerted me to the fact that Spectrum Techniques makes a preamp designed for Proportional Counters. There is not reference to it on their website, but the product manual with schematic is still there on the server:?
They are using an AD823 - Analog Devices Dual FET OpAmp. So that seems to be the solution.
Well, a very skeletal form of the Wiki is up. I setup the home page and created a basic structure for the information. As an experiment, I wrote up a page on NIM modules. It's all very rough, but it works. It will be interesting to see where it goes. As I read old posts I'll cut and paste useful information into appropriate places on the Wiki. I'm not sure if I need to cite who wrote the post or not. What would be nice is to populate the pages with quotes from posts and then have members go back and create a smoother page that reads more like an encyclopedia entry. But, even if that never happens, it would be great just to have useful insights and reference material in one organized place.?
Normally a wiki requires the use of a special markup language, but this is edited with the exact same tools as these posts.
As it is currently set, members of the group can see and edit pages on the wiki (I'm not sure if they can create new pages or not), but the wiki is not visible to the public. Maybe when its a little more refined it could be open for public view or not. You guys can decide.?
----- Original Message ----- From: Soren <justinhuber@...> To: [email protected] Sent: Wed, 09 Dec 2020 10:50:28 -0800 (PST) Subject: Re: [XRF] Proportional Counters and Preamps
Thanks so much.
Yes, as you probably noticed above, there is a link to the 142PC schematic. What's missing is the illusive identity of the Q1 FET and the Q11 BJT. What they actually are probably doesn't matter, but their characteristics are important in choosing a replacement part. Similar products seem to use a 2N3819 or a 2N4860 for Q1. But, I don't quite understand the protection circuit: I'm guessing that when current? (or is it voltage?) exceed a certain level Q11 dumps it too ground to protect in input of the FET (Q1).
As I mention, there is a knowledge gap in my understanding of transistor amps/building blocks. This is actually a good opportunity to learn more about that - I'll pull out the textbooks. I guess OpAmps have made us a bit lazy. I unstained the basic opamp based CSA but I struggle with these diagrams to identify which components make up what is effectively an opamp. I think one of them delineates it and also identifies a buffer circuit.
I know that we're diverging a bit from XRF proper into the hardware realm, but I'm a great believer in DIY hardware since it makes, otherwise expensive hobbies, accessible to the newcomer. (See for example the CERN Particle Detector project: ) Could you imagine if basic XRF technology was accessible to the amateur for under $100-200. I guess Theremino does that to some degree. But I have a (perhaps unreasonable dream) that one day a kit could be put together using an off the shelf SiPIN that with decent energy resolution, whereby a tinkerer could actually build a decent semiconductor XRF system for a few hundred dollars with a faster ADC than a sound card offers. Perhaps it could be a board that interfaces with the GreatFET ( ).
Good. It's done. I had backup moderators on all the old lists. Just haven't gotten around to it on these all these new ones yet. One of the lists is an Archive of the old Yahoo Groups, one for each group.
PS I'm a hardware guy, don't know much about computers.
From: "Justin Huber" <justinhuber@...> To: [email protected] Sent: Wednesday, December 9, 2020 2:33:18 PM Subject: Re: [XRF] Getting the Wiki going
Thanks. If you want you could do this - make me a group monitor and I'll get it going. Then I'll see what kind of access permissions I need in order to maintain it and you can downgrade me to that level. On the groups.io webpage for the group, there is a item named "Wiki" at the bottom of the lefthand menu bar. The most famous wiki, is of course Wikipedia. The idea is that it's a sort of encyclopedia where anyone with proper permissions can create pages and update content on them. I believe that you would not need to be a moderator to edit the pages themselves - just a member of the group.?
The idea is that when members develop information that is more structured than a sporadic post they could add that to the wiki. For example, there could be a page with a running list of mineral samples or reference materials and then you could make a page for each sample and different people could upload their analysis results of that material so it would all be organized in one place.?
Or there could be a page for different categories of equipment and people could post troubleshooting info for particular detectors, etc.
