XRF Wiki
Welcome to the XRF Wiki. This Wiki is a repository of information contributed by members of [email protected]. Members can view and edit the pages. The pages are currently not viewable by the public. The pages below represent a rough overview of the technology and techniques associated with X-Ray Florescence Spectroscopy as well as serving as a place for members to organize the spectra that they have contributed to the forum.?
As a starting point, the pages will be populated by information taken from member posts from the past few years - with references/attribution. Perhaps in time, these pages can be edited by members to make them more complete and less choppy. Members can also edit this page, making the structure of the content more organized.?
Pages can contain information about a particular topic, links to relevant resources (such as manuals, research papers, etc.), links to relevant forum discussions on the topic, book titles, or anything that might be useful.
What follows is very much a work in progress.
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Adding to the Wiki
For those unfamiliar with the Wiki phenomenon, it is basically a user editable encyclopedia. The idea is that there are pages with different articles, which the user can read and also choose to edit if desired. If a piece of information is incorrect, a link outdated, or the presentation choppy or unclear, the user can just click "Edit Page" at the bottom and then fix the mistake. There is also a "Page History," so if you a user were to make a mistake or maliciously destroy a page (which wouldn't happen here) an editor can come along and restore the page to a previous version.?
If you have used MediaWiki (the engine that runs behind the scene of Wikipedia.org) you will be familiar with a certain style of creating an article. There are tags that one uses to change the formatting of the parts of the article. The Wiki on Groups.io uses a different background engine and so the standard MediaWiki syntax does not apply here. Rather, the page is edited using the same tools as one would use to compose a message on the forums. If you are a programmer or someone who likes using the tagged syntax directly, you can access the underlying page source code, be activating the advanced editing toolbar (the icon with three lines on the far right of the basic toolbar) and then clicking on the source code icon <> on the far right of the Advance Editing Toolbar. You will immediately notice that the underlying source code is HTML. Most things can be done just by using the various icons, but advanced features like table can only be implemented by manually writing the source code. (Although there are website available that will generate the source code for you through a graphical interface.)
Here are some useful resources from Groups.io:?
Wiki Guide for Users and Editors
Message Composition Tips and Tricks
Overview of XRF
X-Ray Florescence vs. X-Ray Diffraction
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Hardware
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?]
Amptek XRF System
Activation Sources - what do you use to make the sample fluoresce (that's within the amateur budget and doesn't require special licensing)
Software
- Device Control Software - what do you use to collect the data from the detector system
- XRF Analysis Software - what do you use to analyze the data, especially for quantitative measurements (composition percentages, thin film measurement)
- Free Software Tools
Note: there may be software packages that possess some or all of these characteristics.
Materials Spectra
Metals Spectra
Historic/Archeological Spectra
Reference Materials Spectra
Household Objects Spectra
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Resources
Videos
Articles
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Non-XRF Techniques
Gamma Spectroscopy
Raman Spectroscopy
FTIR - Fourier Transform Infrared Spectroscopy
Atomic Emission Spectroscopy
Inductively Coupled Atomic Emission Spectroscopy
Spark Emission Spectroscopy
Atomic Absorption Spectroscopy
LIBS - Laser Induced Breakdown Spectroscopy
Photoacoustic Spectroscopy
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Re: Small Sample Size XRF with low power (OTHER) excitation
12 hours in to the TXRF run: Pb still present of course, we will attend to that and other details subsequently. Ag- Well formed Ka and Kb peaks. Interference from exciter- detectable but nil- not a
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GEOelectronics@...
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#2158
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Re: Small Sample Size XRF with low power (OTHER) excitation
And here's the finished 30 minute run of the 45 degree angle sample run. With no beam shaping or collimators we were getting 92% deadtime. Now we re-adjusted the angle for TXRF, this may take a while
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GEOelectronics@...
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#2156
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Re: Small Sample Size XRF with low power (OTHER) excitation
Phase II Now moving on to OTHER excitation. Transferring our new-found technical knowledge to other sources of excitation, basically starting all over from the previous TUBE tests. First up- AmX1
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GEOelectronics@...
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#2152
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Re: Small Sample Size XRF with low power (tube) excitation
Good view of the setup. That really is a small angle. Dud Sent: Friday, February 5, 2021 10:02 AM To: [email protected] Subject: Re: [XRF] Small Sample Size XRF with low power (tube) excitation Paper
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Dude
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#2151
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Re: Small Sample Size XRF with low power (tube) excitation
Paper Sample Holder MKIII Smaller disc, kept bigger viewing hole, reduced sample size again, kept spacing between sample and sensor collimator. Sample a maybe 1 or 2 square mm piece of 0.998% silver
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GEOelectronics@...
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#2150
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Re: Small Sample Size XRF with low power (tube) excitation
Follow-up on the paper sample holder calibration samples idea. The paper disc was made bigger as was the hole in the middle. For a this one I wanted a Silver metal sample. Punched a 1/8" disc of
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GEOelectronics@...
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#2149
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Edited
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Re: Small Sample Size XRF with low power (tube) excitation
Same setup and variable as preceding post. This time the sample is Mo metal "stamp". Note: The deadtime is better controlled? by moving sensor away from sample. In a permanent setup IN AIR- it would
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GEOelectronics@...
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#2144
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Re: Small Sample Size XRF with low power (tube) excitation
Followup-1 replaced Mo-Re alloy with a 1/4" X 1/4" flat piece of thick Mo metal. Same setup as Mo-Re, namely 37kV 4.7 uA and 300 seconds. This time there were 3 identical test runs, the changes to
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GEOelectronics@...
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#2143
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Re: Small Sample Size XRF with low power (tube) excitation
Geo, To tell what¡¯s going on in the real low energy region you need a lot of counts to separate noise from closely spaced elements that may be separated by 100ths of a keV. Mo is 2.293, 2.395 while
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Dude
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#2140
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Re: Small Sample Size XRF with low power (tube) excitation
" While Sulfur is at 2. so is Mo La1,2.and in that you have a lot of Mo I¡¯d have to call this Mo La1,2." Will check that tomorrow against a Mo only stamp with same setup. " counts are closer
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GEOelectronics@...
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#2139
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Re: Small Sample Size XRF with low power (tube) excitation
Geo, Lookin' better, PUR is on and fast/ slow counts are closer together yet it still has a 65% dead time and it still has some low energy noise below 0.62 keV that could be taken out. Getting rid of
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Dude
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#2138
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Re: Small Sample Size XRF with low power (tube) excitation
Uh oh. Can we ask everyone to chip in to delay the issue till we find an alternative? What would that take? Dud Sent: Wednesday, February 3, 2021 3:46 PM To: [email protected] Subject: Re: [XRF] Small
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Dude
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#2136
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Re: Small Sample Size XRF with low power (tube) excitation
Mo-Re alloy "stamp" .002" foil, with slight corrosion on one side. 27kV @ 4.7uA 5 min. Beam and sensor collimated to 1mm circle. We are analyzing 0.785 mm^2 of the sample. Sensor moved away from
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GEOelectronics@...
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#2135
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Re: Small Sample Size XRF with low power (tube) excitation
" Geo, When you reply can you please leave the post attached Its hard to reply without knowing which we¡¯re replying to. I think this post was what you¡¯re referring to.:" Doing so has run up our
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GEOelectronics@...
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#2133
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Re: Small Sample Size XRF with low power (tube) excitation
For the last scan (previous post), the sample size was dramatically reduced from a few milligrams to just a few dust particles. Pick any 1mm circle near the middle of the watch-glass-"sample holder"
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GEOelectronics@...
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#2129
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Re: Small Sample Size XRF with low power (tube) excitation
Deadtime taken care of. Changed sample holder and sample, lowered current., increased count time to 10 mins. We were overdriving everything, too big an entrance hole, too big a target! Will change
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GEOelectronics@...
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#2128
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Re: Small Sample Size XRF with low power (tube) excitation
Here is the series of .mcas I ran keeping the HV and current th same, but varying the Peaking Time to see if that had an effect on the deadtime.(it didn't) Geo
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GEOelectronics@...
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#2124
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Re: Small Sample Size XRF with low power (tube) excitation
Next up is the HV being varied and everything else remaining the same. Obviously the filter is messing up the expected output, as we suspected. A few observations- No signal at all below 15kV or so
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GEOelectronics@...
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#2123
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Re: Small Sample Size XRF with low power (tube) excitation
This first data set are the individual test runs with the beam kV set to 30 kV for all tests, varying only the current of the beam to find the relationship between current and peak counts.?. We have
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GEOelectronics@...
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#2121
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Small Sample Size XRF with low power (tube) excitation
The sample is Rainbow Hematite, weight 5 mg. Longest dimension is about 1mm, thickness is a fraction of that. Like a flake. It was a free sample from a supplier, as shown in the watch glass, a total
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GEOelectronics@...
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#2120
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