Measurement of Trinitite sample from New Mexico

Trinitite is a mineral of artificial origin resulting from the first atomic bomb blast at Alamogordo site in New Mexico (USA) on July 16, 1945. At high temeprature which occured in the epicenter of detonation, sand and rocks melted and mixed with products of nuclear fission. After solidification, glassy material known as Trinitite emerged. Even after more than 70 years since Trinity bomb explosion, material is mildly radioactive from products of plutonium fission.

Sample Trinitite
Gamma spectrometer Scintillix SCGS-01
Scintillation probe NaI(Tl) 3"
Integration time 20000 sec
Background correction No
Shield Lead
Software Theremino v.6.3

Nowadays, one can still found nice pieces of Trinitite on the market for reasonable price, but on the other hand, lot of fake samples of Trinitite can be bought. Cheaters usualy sell naturally ocurring radioactive minerals or make counterfeit Trinitite from sand smelted with available radioactive compounds (salts of uranium or thorium), to make slightly radioactive material resembling original Trinitite. Nobody can differentiate true and false Trinitite only with Geiger counter, however gamma spectrometry can be used as one of the ways how to distinguish original and counterfeit Trinitite. Only by this way one can identify characteristic fission products which are present only in original Trinitite. From these radionuclides especially Cs-137, Am-241 and Eu-152 are prominent in the gamma spectrum. Characteristic spectrum of nice original specimen of Trinitite is presented at the following picture:

In the presented gamma spectrum, pekas corresponding to Cs-137 and Am-241 are clearly visible. Also small peaks of Eu-152 can be identified above the noise level.

At the image above is a rig, used for the measurement. It is composed of massive lead shield, Scintillix gamma spectrometer and computer with Theremino MCA software for data acquisition.

Tags : Radioactivity ,   Trinitite ,   Cs-137 ,   Am-241 ,   Eu-152 ,   gammaspectrum

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