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Lead-210 test


The so-called 210Pb test is a partial examination of the “authenticity test” of metal objects, which consists of various examination methods in order to obtain as much information as possible about the object.


In the case of authenticity checks, it is often only the interaction of many different pieces of information that make it possible to detect a forgery. Therefore, depending on the type of metal, we offer various analysis methods with which additional information about the chemical composition can be determined. In this way, it can be determined whether the metal contains modern alloying elements or whether the alloy is untypical for the presumed timing.

In principle, different metals can be examined with the 210Pb test: copper alloys (copper, bronze, brass), silver, tin and lead. If these metals were produced only a few decades ago (maximum 150 years), the metal usually contains small, measurable amounts of radioactivity. However, unlike in the geosciences, where younger sediment layers can be dated using the 210Pb method, this method does not provide information on the age of metal objects, because the initial concentration at time 0, i.e. when the metal was produced, is unknown and varies greatly depending on the type of ore and the deposit.


In nature, lead consists of four stable isotopes, i.e. types of atoms of an element with different masses (204Pb, 206Pb, 207Pb and 208Pb), which, apart from 204Pb, are all formed by the radioactive decay of uranium and thorium. 210Pb is part of one of these natural uranium decay series. It is formed as an intermediate product of the 238U decay series, at the end of which is the stable 206Pb. In nature, there is usually a so-called secular equilibrium, in which all the intermediates (daughters) have the same activity. One of these intermediates in the 238U decay series is 210Pb with a half-life of 22.3 years.

Many ores contain uranium and the various radioactive elements of its derivatives in low concentrations. During the smelting of ores, these elements behave differently, which leads to an interruption of the decay series. The so-called lithophilic elements accumulate in the slag. These include uranium and other long-lived intermediate products of the decay chain, while lead (and thus also the radioactive 210Pb) and some other very short-lived radionuclides (e.g. 214Bi) are absorbed by the metal. Due to the interruption of the decay series, no new 210Pb can be produced in the metal by the radioactive decay of uranium. As a result, this means that every freshly produced non-ferrous metal and silver is (weakly) radioactive, but this radioactivity decays more and more over time. In the metal, 210Pb is the isotope with the longest half-life (22.3 years), which can still be detected for about 100-150 years. After five to six half-lives, only one to three percent of the original radioactivity is left, which often can no longer be detected. The detection of 210Pb in copper, bronze, tin, lead or silver means that the metal or alloy was clearly produced in the 20th century (or slightly earlier). We detect 210Pb by measuring the secondary product 210Po using alpha spectrometry.


It should be noted that the absence of measurable activity of 210Pb is not evidence of age beyond 100 to 120 years, as old metal could have been used or perhaps exceptionally pure starting materials were used in metal production.

Sample properties

Metals (copper, silver, tin and lead alloys): at least 20 mg bright metal, as free as possible from corrosion and surface material.

Other materials on request.