X Ray Fluorescence
Illuminating radioactive substances with a radioactive source you excite the electrons of their atoms which then decays emit energy x-ray characteristics. For example,, in the image above, concerning analysis of silver gilt, Silver features energies were detected (electronic shell K ) and dell’ Gold (electronic shell L).
With this technique you can distinguish many materials, including silver, and even see through the plating, What is the base material.
With the energy that we provide is most likely to affect the electrons in the first shell (K), the innermost (less energy). The vacuum must be filled necessarily (to the laws of quantum mechanics) from another electron, from an outer shell and then with greater energy. Excess energy is emitted as photons with an energy characteristic that depends on the item and the electronic shell interested. The electronic shell concerned depends on the energy that we provide. Using americium (59 Kev). We can only examine substances with binding energies, in K shell, less than about 50 Kev – for metals with high binding energies we can examine the second shell, named L, and through this we can analyze most elements atomic number, like gold.
Documentation about XRF techniques
This four-page white paper explains everything you need to know about XRF techniques. The document also contains reference tables on the energies of the most important elements for these analyses. Everyone should download it and keep it handy.
Those wishing to make fixes and translations into other languages can download this compressed file that contains the originals in ODT format (Open Office): XrayFluorescence_ODT_Files
Many researchers are active in research and XRF are already available guidelines for building efficient and simple sensors.
The recommendations to minimize the noise PmtAdapter
The most interesting links:
In the following PDF file you see a great realization of probe for low energies. The quality of the probe is great, in a very short time of only 120 seconds, provides precise and obvious lines. In addition to the construction of the probe on file shows the lines of many materials including Zinc, Copper, Silver, Gold, White Gold, Nickel, Carbon steel and thin gold Plating. Low energie.pdf probe (file posted by Mario Mueller of death on Gamma Spectrometry in this forum messaggio_12740)
Research on antiques
This file: Test_Sr90_Am241 view part of our research collaborator. This is a comparison between the illuminator and Sr-90 Am-241. The best results were obtained with 4 uCurie of americium placed in 4 buttons all around a ring of lead shielding that prevents gamma radiation of americium to directly hit the Crystal scintillator.
This second file: Tibetan_InkPot_And_Container view tests on some Tibetan objects. NET and precise results. And’ now proved that with americium can do precision analysis in a very short time.
This image shows a filter for herbal infusions purchased in Russia, in a store for foreigners, at the time of Gorbachev. Had been sold as silver gilt – XRF analysis shows that the salesman had told the truth. In this picture the illuminator is the green plastic disk containing Sr-90.
In this document a comparison of two seemingly similar objects, the XRF distinguished sharply.
And in this ChineeseFruits a new interesting research. A test on the possibility of revealing the presence of arsenic in the pigments of ancient ceramic objects.
Finally this XRF_Additional_Notes focuses on the differences in results obtained using as illuminator the Sr-90 or the Am-241.
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