O01_P05

³²Si – An alternative radionuclide for dating the recent past?

Schlomberg M¹, Vockenhuber C¹, Synal H¹

¹Laboratory of Ion Beam Physics, ETH Zurich, Zurich, Switzerland

Dating the last few hundred years is challenging with currently used radionuclides: To date with ¹⁴C (half-life of 5700 a) is difficult due to ambiguities in the calibration curve in the last ~400 years, although the last 80 years can be again well dated due to the bomb peak of the ¹⁴C concentration and its subsequent dilution. Dating methods based on shorter-lived nuclides like ³H (12.3 a) and ²¹⁰Pb (22.3 a) can only be used in the last ~100 a. A promising candidate for filling this dating gap is cosmogenic ³²Si with a half-life of ~150 a.

However, the application of ³²Si has so far been limited by the imprecisely known half-life. As part of the SINCHRON collaboration which aims at a redetermination of the half-life of ³²Si, the Laboratory of Ion Beam Physics (LIP) at ETH Zurich will perform the AMS measurements for the determination of the absolute number of ³²Si atoms in samples used for activity measurements.

In this poster, the potential of ³²Si as dating tool is discussed and an overview of the previous half life measurements is given. First results concerning the AMS measurement technique are presented and an outlook for potential ³²Si measurements in environmental samples is given.