X ray of Ag and Nb

[Peter-1]

In order to test my setup I tried to show the radiation of silver and niobium with an excitation by americium. Is the result ok ?

2016_12_09-Xray-Ag.jpg

2016_12_10-Xray-Nb.jpg

Peter

[Sesselmann]

Peter,

Looks like you got a pretty good result. The x-ray tables on http://nucleardata.nuclear.lu.se/ indicate highest intensity around the same energies as your peaks.

Someone should take this opportunity and develop a compact low cost xrf device for metal testing, the only product out there at the moment is a hand held device made by Thermo-Fisher and it sells for around $15,000. There would be an instant market in the precious metals trade.

Steven

[lodovico]

Hello,
this is my low cost diy XRF : http://physicsopenlab.org/2016/02/24/di ... ctrometry/ and in the post you can find a document with all the spectra.
I tested almost every element, at least the elements heavier than Chromium ...
The silver XRF spectrum is ok, but the niobium one could be improved maybe with backgrond subtraction.

Lodovico

[Sesselmann]

Lodovico,

Nice work, it's very similar to the one I built, I think you had more Am sources on your experiment which makes the result faster.

To be useful in the precious metal industry we need to also quantify the isotope, not just identify it. So when sampling gold alloys of unknown purity the software has to calculate the percentage of each element present. Say for a piece of 14 carat yellow gold the program output should be

Au 58.5%
Ag 10.0%
Cu 25.0 %
Zn 6.5 %
---------------
Sum 100%

I managed to achieve reasonably close results by taking the sum of counts in the region of interest of the x-ray peak, but it can be tricky when peaks are close together.

Also for testing gold, the 59 keV Am x-ray source doesn't really have enough energy, a 85-90 keV source would be better.

Steven

[Peter-1]

hello
this is my last attemp with a small peace of zirkonium 40 Zr.

Xray-40Zr.jpg

Now i will test if it is possible to come down to 10 keV.
Peter

[sgt_bear]

Someone should take this opportunity and develop a compact low cost xrf device for metal testing, the only product out there at the moment is a hand held device made by Thermo-Fisher and it sells for around $15,000. There would be an instant market in the precious metals maket

Steve,

I guess it would be hard to develop a commercial product for a low price. Most of the cost goes in to develompent - specifically into rules and regulations. E.g. here in Switzerland, to sell an electronic product, even a "hobby kit" (like a bare pcb with loose parts), you have to be accepted by numerous federal departments. They don't will approve and test your product for free, so for my hobby tube clock, i would have to pay around 10'000$ to make it possible to sell it legally.

I guess, for a device that includes radiation, a LOT of other rules. So even if you develop a system by yourself (no workers that want money), that would cost 100$ to produce, the cost of get the product approved would be around 50'000$.

[Sesselmann]

I agree, any XRF device would obviously emit x-rays and that complicates the compliance process. Many of these compliance requirements are sold to governments under the banner of "safety" but in many cases its just a way for some large companies to have a monopoly on a product or on testing those products. I recently tried importing a batch of $4.00 12V power adaptors from China and was quoted $11,000 to have it checked by an authorised approval agent.

[stamasd]

Also for testing gold, the 59 keV Am x-ray source doesn't really have enough energy, a 85-90 keV source would be better.

Steven

Cd-109 maybe? Single energy gamma at 88keV (but also gives some Xrays around 22keV so these should be taken into account)

[Sesselmann]

Silviu,

Yes I see Cd-109 is available from Spectrum techniques. http://www.spectrumtechniques.com/produ ... dmium-109/

The relatively short half life of around 1 year means it will need to be replaced soon, might be worth trying for an experiment. 100 MBq at 3.6% intensity is around 361 kcps of the 88 kV gamma isotropic, but by the time you collimate it for XRF use, and factor it by the number of gamma that interact with the source, it may not yield much.

Building a miniature x-ray source might be more practical.

Steven

[stamasd]

Hm, I'm not sure what a miniature 90keV Xray source suitable for spectroscopy would look like... Especially the power supply. The smallest Xray machines I'm familiar with (dental) peak at about 70keV if I'm not mistaken, but then don't give out a neat peak at that energy but rather a continuum of Xrays with energies up to that level (due to lack of stabilization of the high voltage and the nature of the bremmstahlung radiation). I think it would be messy to separate the peaks of interest from this sort of input. A nice monoenergetic isotope should be cleaner to work with.