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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

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

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

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

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

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

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

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

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

" 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

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

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

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

" 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

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"

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

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

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

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

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