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Argonite? just a guess, any clues to look for?. Huge calcium, Fe and good Zn plus others.

Geo, Attached are the 15 and 40 kV shots of the small obsidian arrow head #1 and the assay results Except for the small obsidian chip #4 which lacked Sr they all had the same elements and close assays. Except for #4 and #5 I believe they were all from the same place as they are semitransparent in places and show darker banding in them The Arrow head #1 contained K 3.8% Fe 6306 ppm Ca 4818 Ti 1356 Zr 293 Mn 280 Rb 205 Ba 657 Sr 76 Pb 27 Zn 29 Cu <9 Ga and As peak were id’d but no cal. Run a 40 and 15 kV shot on your obsidian using a standard 45 deg beam incidence and lest see what that shows. Do you know where it came from? Dud From: dfemer [mailto:dfemer@...] Sent: Wednesday, December 30, 2020 7:29 PM To: '[email protected]' Subject: RE: [XRF] Skimming angle XRF- Experiment Geo, Well that figures. It doesn’t seem to be very efficient and with a lot of backscatter. Don’t feel bad about Si even I can barely pull it out. Ca is easier. I ran some Obsidian points today and I’ll post them tomorrow some time. Most are K, Ca, Fe, Mn, Ti, Rb, and Zr dominant. We need to see a variety from different locales as mine seem to be from the same area except for one. I’ll see if I have some more laying around and run them. Dud From: [email protected] [mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Wednesday, December 30, 2020 7:10 PM To: [email protected] Subject: Re: [XRF] Skimming angle XRF- Experiment Dud It is exactly backwards. It is called Grazing Emission (of XRF) (GERF), what you are describing is the other one, Gracing Incidence (of beam) where the detector looks at the flat target (GIRF). And it works, they all work, but have different qualities and quantities. But I can't see Si well at all. Never could really, no matter. Even with a 2" X 1/4" thick pure silicon disc. Even Ca is a challenge. Metals we are good to go. Geo _____ From: "DFEMER" <dfemer@...> To: [email protected] Sent: Wednesday, December 30, 2020 2:51:32 PM Subject: Re: [XRF] Skimming angle XRF- Experiment Geo, I think he collimated x-ray grazing angle should be <0.5 degrees across the flat target surface and the detector would be at a 90 degrees to the flat surface. This looks backwards. This also only works for near surface elements. Note the large X-ray tube Compton which you shouldn’t see with a Bragg grazing angle. Strange spectra it certainly needed more time but no Si which is mostly what Obsidian is made of. The Zr is odd. I need to run some obsidian and see what it shows. Can you do a regular shot of this piece. Anyone one else with some obsidian can you take a shot. Dud From: [email protected] [mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Wednesday, December 30, 2020 11:06 AM To: [email protected] Subject: Re: [XRF] Skimming angle XRF- Experiment Putting the Grazing Emission XRF (GEXF) to work. A little impromptu jig set up for flat items. To remind, the beam comes in from the bottom, spreads out into a cone, We apply a tubular collimator in that beam, shielding all but a central 1mm round clear passage. The collimator is further shielded with a thick brass cylinder, allowing the 1mm collimated beam to exit the top. Just above that exit port the beam has spread very little. Into the beam at the appropriate distance is placed the target, the positioning now facilitated by this little jig arrangement, perfectly suited for flat items. Then the beam strikes the bottom surface of the target sending XRF rays back out in every direction (4Pi Steradian, i.e. isotropic), some of which we detect by a sensor placed at a convenient edge of the target. It is far simpler than it sounds, and allows for a clean scan for elements, with very low beam power (5 microamps) and the HV is adjusted manually to the lowest possible value that will excite the atoms in the target. Tourist-trap obsidian arrowhead, perfectly flat on the bottom: disc-spacers-small.jpg A slight change in the layout- a 2" thick lead glass viewing window is added between the beam port area and the scatter shield, in lieu of a Pb chamber over the whole area. Pb-Window-small.jpg Results: Iron, zirconium, other things. Arrowhead_scan_chart_small.jpg Geo

Analyzing Trinitite with different methods.

Save a dead Zinc-Carbon dry cell from the trash can. Take it apart, save the manganese based electrolytic in a min plastic baggie. Only a gram or 2 is needed, but also save the ZInc metal can and carbon rod for future experiments. XRF the baggie to get precise Mn Kb1 line at 6.49keV and a bonus line from zinc that is included along in the black stuff. Use the Zn Ka1 and Ka2-line average of 8.627keV. Use your exciter for the top end= 59.54keV. Geo

Dave, Attached are the XRF shots of the two Mt Pass Bastnasite samples you sent me The large sample (#1) that had the galena stringer in it was shot on both sides as well as the "sparkly" stringer which, as you guessed, is Galena - PbS. See the Eckhart log file for the positive ID picks, other elements in the shot files are not verified due to peak over lap or no confirming Kb or Lb peak. The percentages are higher than actual as the calibrate that was used was for ppm level elements which will over report percentages in this mode. Bastnasite is (Ce,La)CO3F and in this case is hosted in a Carbonatite which is an igneous sourced rock with predominantly carbonate minerals but also having the siliceous , oxide, and phosphate type mineralization In these samples we see Ca S, P, Fe, Sr, and Ba dominating. For the rare earth elements Ce and La, dominate but Nd, Pr and some Nb are also seen. The P is most probably due to apatite or some monazite. Surprisingly the U and Th content is below the detection level and that was unexpected as my prospecting around the Mt pass complex has shown high Th with some U. I suspect the high Sr and Ba are from Barite (Ba, Sr) SO4 while the Fe and S are due to pyrite FeS2 The highest Ce is found in the large #1 galena stringer sample at 1.8% Ce with La at 1.2%. The Galena stringer has a Pb content of 10.6% with 11 ppm Cd. Cd is commonly associated with Galena. In general the Pb in the other samples are much lower. The small sample # 2 had a 1.1% Pb content and had what looked like an oxidized galena coating under the microscope. I also included a shot of "Mt Pass MolyCorp White Earth Concentrate" that was in a 5 gallon bucket I sub sampled from a company going out of business. While it said "White Earth Concentrate" it is actually a dark grey powder. Its elemental composition is predominantly Ti and Ca. The Ba and Sr are low in the 100's of ppm and its slightly radioactive with Th at 239 ppm. Nb is at 2602 ,Nd 3138, Pr 819, Ce 7136, La 2973 and Zr at 803 ppm. Quite a bit different than the actual rocks. This was a nice host rock sample set showing what the actual carbonatite looks like rather than running a crystal of just bastnasite which one usually gets. Dud KK7IF

Hi guys This is a 316L stainless steel monofilament Used as a sternal suture during open heart surgery. Elements detected are chromium,iron and nickel Taray

Hi guys Here is a 50g orpiment arsenic sulphide crystal from China. It is yellow with some shades of red. When red,it can be mistaken for ruby Taray

Geo, I’m not sure this post made it through so I’m resending it. Dud From: dfemer [mailto:dfemer@...] Sent: Saturday, December 19, 2020 3:37 PM To: '[email protected]' Subject: RE: [GammaSpectrometryGroup] Mystery Ant Hill Sand Geo, Its kinda hard for us to figure out what going on without seeing it or having a better description Dark stones – was it just a surface coating? Did the acid wash it off and then were they were all white or what color. You have a mixture in the bag. That needs sorting by color and texture. Did the white appear when scratched on the streak plate or after washing and if so what was the “white” stone streak? There’s something going on here we don’t understand. A dark coating on a white rock cold be a manganese coating from surface weathering. (pyrolusite). That will scratch off but I don’t think acid will remove it so what’s the coating? Hmmm. See attach mca The first broad peak between 3.3 and 3.7 is K and Ca with what appears to be more Ca. The next ROI peak at 6.35 is Fe Ka1 with its Kb1 at 7.05 The next ROI at 8.01 is Cu Ka1 Ka2 The next peak at 8.58 (no ROI) is Zn Ka1 The next ROI at 10.51 is Pb La1 and La2 The next ROI at 11.82 (your Br Ka1 pick) is actually the Si escape peak from the Rb Ka1 at 13.36. The next ROI at 12.6 is the Si escape peak from Sr Ka1 is and probably combined with Pb Lb1, 2 for that fat peak The Next ROI at 14.14 is Sr Ka1,2 The next broad non ROI peak is the Rb Kb3 The Next ROI at 15.73 is unresolved and could be Srr and Zr mixed together. What I see here is based on the magnetite (Fe), Rb, Sr, K, and Ca is a granitic source with Qtz (although we can’t see the Si at 1.7), Mica (Rb, Fe) Feldspar (K) orthoclase(K) or possibly Plagioclase (Ca) (if it’s not calcite/caliche contamination mixed in). The possibility of Zr would also lend its self to a granitic source material. Here’s some recommendations. 1. Your lower limit LLD was set at 1.59% Looks like it could be set lower as the peaking time and filters were set perfect looking at the input and total count counts. I’m not sure what beam current you were using but the count rate is low so it’s set well. Look at your dead time and tweak up the beam current up or down to optimize count times. 2. The beam voltage is too low for what you’re looking for. I run 50 kV, 40 kV and 10 or 15 kV starting high. The X-ray tube Compton has interfered with the 20 Kv range where the action is. Running only a low beam voltage loses a lot of high Ka info that may be needed for confirmation. Start high then pick the Hv range to look at for what you see down low. It’s just a first look to get scope and scale 3. The low energy resolution here is poor in separating the K and Ca. A 15 kV shot may help resolve that although the Si Pin may not have enough resolution to pull them apart. Try and let’s see. 4. If you have a strong peak start there and look for a escape peaks, it’ll save a lot of false positives and the “what the heck is THAT” time. If you have a lot strong peaks don’t forget to the eliminate sum peaks. Then go after the rest of the herd. 5. Don’t mix colors – separate by color. The feldspars are the most likely to host Eu. Sort them out by color start with pink. Sort by streak plate color then run the separations separately and find out what’s hot and what’s not. Dud From: [email protected] [mailto:[email protected]] On Behalf Of GEOelectronics@... Sent: Friday, December 18, 2020 10:12 PM To: [email protected] Subject: Re: [GammaSpectrometryGroup] Mystery Ant Hill Sand Ok Dud, the streak test of the dark stones produced no streak on the white plate. Where it scratched the stone itself is white underneath, so it made a white streak I guess. Then they were all acid washed (the contents of the yellow Tupperware cup), after which all the dark stones disappeared, being replaced with white ones, pink ones and several other colors including clear and cloudy quartz. Looking at the white ones under magnification, there are tiny black specks present. Testing with a strong magnet sho

I'm currently working on getting a SiPIN setup, similar to the GEO 1-2-3 pictured in this June thread: /g/XRF/topic/geo_1_2_3_all_in_one_low/75030400 The power supply and pulse processor are already in a X123 case, but the detector/preamp are in the form of a bare OEM board - connected with a ribbon cable. I need to attach a proper heatsink before I can safely turn this on and I should probably shield the board as well to minimize EMI problems. I have a couple questions about heatsinks: 1. Electrical Insulation - How do you electrically isolate the detector from the heatsink, while maintaining thermal conductivity. Geo - one of the pictures shows a small white disc/separator. Is that PTFE? Or something more exotic. I have a bunch of mica and was thinking of using that - only .77W/mK but very thin. 2. Heatsink Size - I'm trying to figure out sizing for the heatsink. I know that the GEO123 uses the case as a heatsink, but I've also read on some of the other threads about using metal blocks as additional thermal masses - I think that Taray mentioned this. The stock Amptek OEM heatsink looks like just a piece of extruded aluminum angle, but I have to assume that this must be bolted to something larger. I have a giant PC heatsink with aluminum fins connected by some heat-pipes but I get the impression that using a fan would be a big no-no because of potential issues with vibrations. How to you figure out a proper size? There seems to be some discussion in this thread: /g/XRF/topic/77526205 3. Protecting the leads - how do you keep the 12 lead/pins coming out of the detector from shorting on the metal case/heatsink? Are you using small pieces of heat-shrink tubing for this? Thanks, Soren

Hi guys Using 6 Am241 /ludlum lead disc glued to cardboard box Si pin near orifice Due to the shape of detector and fear of samples potentially damaging Be window,I opted for this way Anyway it is only a prototype. Accidentally glued one the Am buttons upside down and it is really stuck Will fix it next time.. Samples as follows 1 Selenium Was discussed in the old forum My sample is a centrifuged suspension of selenium sulphide(selsen) in a plastic sample container .It has remained the same since preparation about 2 years ago It sticks like a coating so without a container,alpha is active. 2 X ray apron polymer Nowadays they are lead free and consist of polymers mixed with antimony,tungsten or bismuth etc to make it light weight I always thought there was antimony present in my sample from my previous xrf experiments.It appears to Tin here?? 3 Bipp a bismuth iodine medical paste 4 Mn 99.7% purity in a plastic container Thanks Taray

Hi guys Here is a scan of gadolinium about 10 grams of high purity with Am241. Sample packed in thin kitchen plastic wrapper, Actually did 2 scans Due to small sample size ,I mounted it on a twig with tape and did an overnight scan. Next morning noted sample fell off from mount resulting in a slightly distorted spectrum. Repeated a second scan with a shorter time frame with rubber band. The longer scan show the L lines better The shorter scan show the K lines better The Gd spectrum pic from internet using 40 KV x-ray. Taray

Hi guys I sometimes use modelling clay as a mount to hold odd shape samples . This "clay" is usually made of calcium salts,petroleum jelly and aliphatic acids. This xrf is for a red clay. The xrf show a prominent calcium peak. This show si pin detectors can detect Ca clearly There may some other peaks due to the pigment used There could be a sinister Pb peak but the count rates are low Taray

Hi guys Here is an xrf of a cut and polished obsidian rock. It is brownish black and glassy. There are several peaks Some appear to fall within the Compton scatter region I attempted to identify some peaks Could be missing some too due to matrix effect Taray

Hi guys I have done this before in the old forum This time with better results My faucet spout has a silvery shiny surface with some mottling.Blocked by water deposits due water stagnation. But I have a confession to make The faucet was mounted on white rounded plaster holder at the base Not in the path of the primary beam The results show various elements Ni,Cu,Zn ,Pb and perhaps Fe Ni is the shiny outer coating Zinc is the faucet spout Cu is coming from brass within (Cu and Zn) Pb from solder? Fe if present from plates/escutcheon ? Zn causing corrosion and heavy deposits This cheap Chinese Zn faucet is a bad choice Deposits are contributing too That will be another topic Taray

Here is the Chunk, I guess it could be copper but as shiny as buffed copper? after 75+ years. Scott

Hi Justin and welcome to our small but intense group of XRF'ers. Also noticed you joined GammaSpectrometryGroup. We try to keep XRF Group centered on advanced XRF topics (SDD, SI-PIN, CdTe, CZT detectors, NIM etc), and GammaSpectrometry for everything else having to do with advanced Gamma Spec work. For general radiation, detection thereof, and all things THEREMINO, use the GammaSpectroscopy (not GammaSPectrometry) group. George Dowell "Geo" PS many of us on all these groups are also Ham Radio enthusiasts. Geo>K0FF