Isobar separation of ³²Si and ³²S – Towards the redetermination of the half-life of ³²Si

Mr Matthias Schlomberg1, Dr Christof Vockenhuber1, Prof Hans-Arno Synal1, Dr Dorothea Schuman2, Dr Ionut Mihalcea2, Mario Veicht2, Prof Anton Wallner3

1ETH Zurich, , Switzerland, 2PSI, , Switzerland, 3HZDR/ANU, , Australia

The ³²Si is a cosmogenic, long-lived radionuclide with potentially interesting applications for dating the recent past. However, its half-life of about 150 years is still not known with sufficient precision despite several independent measurements over the past four decades. The SINCHRON collaboration with partners from PSI, CHUV, PTB, ANU and ETH aims at a comprehensive redetermination of the half-life of ³²Si.
The Laboratory of Ion Beam Physics (LIP) at ETH Zurich will perform the AMS measurements using the 6 MV-Tandem facility for the determination of the number of ³²Si atoms in the samples used for the activity measurement. In addition to the challenge of performing an absolute measurement without having standards available, ³²Si must be separated from its intense isobar ³²S.
We developed a method based on a passive gas absorber in front of a gas ionization detector that allows us the detection of ³²Si by stopping the isobar ³²S at 30 MeV. However, background from light recoils from the absorber material and deviations of the stopping power at low energies still pose challenges.
An overview of the SINCHRON project will be presented. The setup and the obtained data will be discussed with respect to an absolute measurement.


1996 year of birth
2017 BSc ETH
2019 MSc ETH
2019-today PhD at LIP at ETH Zurich

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Nov 18 2021


10:45 am - 11:30 am