Start Carbon 4 dating

Carbon 4 dating

A new way to carbon-date old samples has been developed by physicists in Italy.

By measuring how quickly the sample absorbed the laser light, the researchers were able to work out the proportion of carbon-14 that it contained.

They measured concentrations of radiocarbon as low as four parts in 10, but De Natale believes their system can be improved further.

This new method is based on infrared laser spectroscopy, which probes the quantized vibrational modes of molecules.

A specific type of molecule will absorb infrared light only at energies corresponding to its vibrational modes.

The researchers claim that their idea could have other applications, including biomedical procedures, environmental monitoring, fundamental physics and explosives detection.

Carbon dating is an essential tool of modern archaeology because it allows the age of a biological sample to be determined from the radioactivity of its carbon compounds.

"It is an incredibly sensitive measurement of a very small quantity of this very rare isotope," says David Nelson, atmospheric scientist at Aerodyne Research in the US.

However, he points out that the technique benefits from the fact that carbon dioxide "has an extraordinarily strong infrared line strength.

Because the laser light is injected into the cavity in advance and switched off during the measurement, SCAR is not affected by fluctuations in laser intensity.

Another benefit of the technique is that the multiple reflections ensure that the light interacts with the gas for a much longer time than if the laser were just fired through a sample.

Therefore, the concentration of a particular molecule in a sample can be measured by tuning a laser to the appropriate energy and measuring how much light is absorbed.