Heinrich Wilsenach (IKTP): Long Live Alpha Decay

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Abstract:

Long-lived alpha decays are some of the rarest processes known to man. These radioactive isotopes have half-lives longer than the age of the Universe. To measure this poses a significant experimental challenge. New techniques have been developed to achieve this goal. This work is focused on the improvement of the half-life values used for chronological dating as well as their production rate. Measuring radioactive nuclides with half-lives much longer than the age of the universe helps to achieve this goal. This work will present an ionisation chamber specifically designed for this purpose.
State of the art Monte Carlo techniques have been used to simulate the chamber down to the pulse shape level. The findings of which have been used to define rigorous data cuts. The background suppression of this device is unrivalled in the world. The measurements of the half-lives of ¹⁹⁰Pt, ¹⁴⁷Sm and ²¹⁰Po will be presented in this work. These measurements employ solid-state techniques that are able to characterise the sample geometry to nm precision. In addition, the measurement of the ¹⁴⁴Sm(α,γ)¹⁴⁸Gd nucleosynthesis cross-section will also be presented. The results of this work will help to improve the half-life values used in the field of cosmo and geochronology.