15.5.2020 Measuring the charge radii of radioactive palladium nuclei for the first time (Geldhof)

Some of the fundamental properties of atomic nuclei are their size, shape and mass. These properties are crucial for understanding the nuclear structure, and provide a foothold for studies of various nuclear phenomena such as fission and radioactive decay. In this work, the nuclear charge radii of radioactive palladium isotopes were studied for the first time. This was achieved using the collinear laser spectroscopy technique at the IGISOL facility. As part of her dissertation, M.Sc. Sarina Geldhof conducted the preparation for this experiment, participated in the experiment and performed the data analysis. The radii give information on the size and shape of the nuclei, which can be used to understand the underlying nucleon interactions and variations in the structure of the nuclei as one adds or removes neutrons.
Published
15.5.2020

Radioactive palladium isotopes had not been studied using laser spectroscopy so far due to several experimental limitations. These have now been overcome thanks to recent upgrades to the collinear laser spectroscopy setup at IGISOL, with researchers embarking on a new experimental programme to study palladium and neighbouring elements including silver and technetium. The radii of four even-mass radioactive palladium isotopes, from mass 112 to 118, as well as all stable isotopes were measured in this experiment.
It was conducted by an international collaboration led by researchers from the Department of Physics of the University of Jyväskylä, with support from the Universities of Manchester and Liverpool in the UK, and from the GANIL facility in France.

Laser spectroscopy does not interrogate the nucleus directly, but probes the miniscule effect the nucleus has on the orbiting electrons. This requires highly precise and stable lasers. Technical work related to this was conducted by Sarina Geldhof as part of her dissertation.

The measured radii have been compared to state-of-the-art nuclear theoretical models. Properly reproducing radii is an important test of these models, as it requires the theory to correctly predict both the bulk size of the nucleus, and subtle effects such as its shape. The new data was compared to both existing theoretical calculations, and new calculations performed by Dr. Markus Kortelainen.

This brings us one step closer to finding a global nuclear theory which correctly reproduces known nuclear properties, and can be used to predict the properties of nuclei yet to be discovered.

The dissertation is published in JYU Dissertations series, number 216, Jyväskylä, 2020. ISBN 978-951-39-8156-3 (PDF), URN:ISBN:978-951-39-8156-3, ISSN 2489-9003
Link to publication:

M.Sc. Sarina Geldhof defends her doctoral dissertation in Physics "Developments for high-resolution laser spectroscopy and application to palladium isotopes" on Friday 15 of May starting at 12 at the Department of Physics at the Ä¢¹½Ö±²¥. Opponent is Professor Kieran Flanagan from the University of Manchester (UK) and Custos is Professor Iain D. Moore from the Ä¢¹½Ö±²¥. The doctoral dissertation is held in English.

The dissertation is held online. Link to the Zoom Webinar (Zoom application or Google Chrome web browser recommended): 

For further information:
Sarina Geldhof, sarina.m.geldhof@jyu.fi

Communications officer Tanja Heikkinen, tanja.s.heikkinen@jyu.fi, tel. 358 50 581 8351
The Faculty of Mathematics and Science:
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