TOWARDS ULTRA-COLD GASES OF CAESIUM ISOMERS: PROGRESS AND PERSPECTIVES

General ILL Seminar organised by College III

Wednesday, 3 October 2018 at 11:00. a.m
Seminar room 7/8, ILL 1

Prof. Ferruccio Renzoni
Department of Physics and Astronomy, University College London, London, UK

University College London and IGISOL have recently commissioned a facility for the production, laser cooling, and trapping of ultra-cold Caesium isotopes and isomers at the Accelerator Laboratory of the University of Jyväskylä (Finland). In this talk, we will report on the design, installation, and test of the experimental facility, and on its latest results. The desired A,AmCs species is produced by proton-induced fission or fusion-evaporation in the IGISOL-4 facility [1]. A,AmCs+ are electrostatically extracted, accelerated to 30 keV, mass separated, and routed to the “cold” experimental chamber. Here, thin foil implantation allows creation of a stable thermal vapour of neutral A,AmCs atoms, which are then laser cooled and trapped in a magneto-optical trap. At the current stage A,AmCs is brought from 104 eV to 10-8 eV in around 5 s, at full capacity.
Availability of ultra-cold (≤10-4 K) samples of unstable Cs isotopes and isomers opens new perspectives for a deeper insight into the nuclear structure and for the investigation of many-body physics at the nuclear level. In particular, direct comparison of optical transitions shifts in ACs/ AmCs pairs provides novel data for investigating the charge radii variations and the nuclear shape. Furthermore, the possibility of selectively trapping and detecting small traces of given Cs isotopes constitutes the building block of a new, highly sensitive approach to nuclear forensics, and related applications in environmental control and security. Finally, perspectives on the realisation of an isomeric Bose-Einstein condensate and of the long-awaited experimental demonstration of coherent gamma photons generation will be also presented [2].

ACKNOWLEDGMENTS
This work was partially funded by the H2020-EU.1.3.2 programme through the Marie Curie Fellowship 2020-MSCA- IF-2014 “GAMMALAS” (Proj. Ref. 657188), and by the Royal Society (IE151199).

REFERENCES
[1] I. D. Moore, et al., Nucl. Instrum. Meth. B, 317, 208, 2013. DOI: 10.1016/j.nimb.2013.06.036.
[2] L. Marmugi, P. M. Walker, F. Renzoni, Phys. Lett. B 777, 281-285, 2018. DOI: 10.1016/j.physletb.2017.12.036.
[3] A. Giatzoglou et al, Nucl. Instr. Meth., forthcoming.

Syler Degenkolb
(College III Secretary)

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