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Ce asemanare este intre whisky si bomba atomica?
Elementul de legatura este materialul radioactiv: o noua metoda, bazata pe radioactivitate, ii ajuta pe specialisti sa identifice whisky-ul “cu vechime falsificata” – cel care e laudat ca fiind mult mai vechi decat este, de fapt.
O sticla de whisky foarte vechi poate atinge preturi de mii de lire sterline, iar piata este “inundata” de whisky asa-zis invechit, despre care cei care il vand spun ca are sute de ani, dar care nu e, de fapt, decat o licoare spirtoasa fara mare valoare, fabricata abia in urma cu cativa ani. De curand, oamenii de stiinta au descoperit ca vechimea unui whisky poate fi tradata de continutul de substanta radioactiva, absorbita din aer de orzul folosit ca materie prima pentru fabricarea whisky-ului.
Cercetatorii britanici dintr-un laborator specializat in studiul radioactivitatii (Oxford Radiocarbon Accelerator Unit) au descoperit ca pot evalua varsta unui whisky detectand urmele de particule radioactive emise cu prilejul testelor nucleare efectuate in anii ’50. De asemenea, ei folosesc nivelurile radiatiei de fond din mediul inconjurator pentru a afla in ce secol a fost fabricat un anumit whisky. Tehnica, numita datare cu carbon radioactiv, este aceeasi cu cea utilizata de arheologi si paleontologi pentru datarea vestigiilor descoperite. Ea se bazeaza pe faptul ca toate organismele vii absorb, in timpul vietii, carbon 14 (izotop radioactiv al carbonului) prezent in cantitati mici in atmosfera. Datorita testelor nucleare efectuate in anii ‘50, nivelul de carbon 14 in atmosfera a crescut, iar plantele au absorbit cantitati mai mari. Cel mai vechi whisky pe care l-au analizat pana acum specialistii de la Oxford Radiocarbon Accelerator Unit data de la inceputul secolului al XVIII-lea.
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Nuclear bomb tests help to identify fake whisky
Radioactive material flung into the atmosphere by nuclear bomb tests is helping scientists to fight the multi-million pound trade in counterfeit antique malt whisky.
Bottles of vintage whisky can sell for thousands of pounds each, but industry experts claim the market has been flooded with fakes that purport to be several hundred years old but instead contain worthless spirit that was made just a few years ago.
Scientists have found, however, that minute levels of radioactive carbon absorbed by the barley as it grew before it was harvested to make the whisky can betray how old it is.
Researchers at the Oxford Radiocarbon Accelerator Unit, which is funded by the National Environmental Research Council, discovered that they could pinpoint the date a whisky was made by detecting traces of radioactive particles created by nuclear bomb tests in the 1950s.
They can also use natural background levels of radioactivity to identify whiskies that were made in earlier centuries.
Dr Tom Higham, deputy director of the Oxford Radiocarbon Accelerator Unit, said: "It is easy to tell if whisky is fake as if it has been produced since the middle of the twentieth century, it has a very distinctive signature.
"With whiskies that are older, we can get a range of dates but we can usually tell which century it came from. The earliest whisky we have dated came from the 1700s and most have been from 19th century.
"So far there have probably been more fakes among the samples we've tested than real examples of old whisky."
The technique the scientists use is known as radiocarbon dating and is more commonly used by archaeologists to date ancient fragments of bone and wood.
It relies upon the fact that all living organisms absorb low levels of a radioactive isotope known as carbon 14, a heavy form of carbon which is present in low levels in the atmosphere.
After death, levels of this isotope in animal and plant remains will slowly decay away, meaning scientists can estimate their age from the amount of carbon 14 that remains in the sample.
Nuclear bomb testing in the 1950s saw levels of carbon 14 in the atmosphere rise around the world and so the amount of isotope absorbed by living organisms since this time has been artificially elevated.
Most of the tests on whiskies have been conducted for the Scotch Whisky Research Institute, which is responsible for analysing the authenticity of Scotch malt whisky.
Phials of whisky extracted from the antique bottles are sent to the laboratory in Oxford, where the scientists burn the liquid and bombard the resulting gas with electrically charged particles so they can measure the quantities of carbon 14 in the sample.
In one recent case, a bottle of 1856 Macallan Rare Reserve, which was expected to sell for up to £20,000, was withdrawn from auction at Christies after the scientists found it had actually been produced in 1950.
David Williamson, from the Scotch Whisky Association, said: "The collectors' market has been growing and the SWA would strongly recommend any prospective buyer takes steps to satisfy themselves as to the product's provenance.
"A range of authenticity tests can be carried out on the liquid and packaging and occasionally, radio carbon dating techniques have been used to assist assessments of the liquid's age."
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