Erlangen 2022 – scientific programme
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MS: Fachverband Massenspektrometrie
MS 4: Accelerator Mass Spectrometry
MS 4.5: Talk
Wednesday, March 16, 2022, 11:45–12:00, MS-H9
Towards the Redetermination of the Half-life of 32Si - Isobar Separation of 32Si from the Isobar 32S — •Matthias Schlomberg, Dr. Christof Vockenhuber, and Prof. Dr. Hans-Arno Synal — Laboratory of Ion Beam Physics, ETH Zürich
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 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 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.