An alternative approach to populate and study the $^{229}$Th nuclear clock isomer
nucl-ex
/ Authors
M. Verlinde, S. Kraemer, J. Moens, K. Chrysaldis, J. G. Correia, S. Cottenier, H. De Witte, D. V. Fedorov, V. N Fedosseev, R. Ferrer
and 17 more authors
L. M. Fraile, S. Geldhof, C. A. Granados, M. Laatiaoui, T. A. L. Lima, P-C Lin, V. Manea, B. A. Marsh, I. Moore, L. M. C. Pereira, S. Raeder, P. Van den Bergh, P. Van Duppen, A. Vantomme, E. Verstraelen, U. Wahl, S. G. Wilkins
/ Abstract
A new approach to observe the radiative decay of the $^{229}$Th nuclear isomer, and to determine its energy and radiative lifetime, is presented. Situated at a uniquely low excitation energy, this nuclear state might be a key ingredient for the development of a nuclear clock, a nuclear laser and the search for time variations of the fundamental constants. The isomer's $γ$ decay towards the ground state will be studied with a high-resolution VUV spectrometer after its production by the $β$ decay of $^{229}$Ac. The novel production method presents a number of advantages asserting its competitive nature with respect to the commonly used $^{233}$U $α$-decay recoil source. In this paper, a feasibility analysis of this new concept, and an experimental investigation of its key ingredients, using a pure $^{229}$Ac ion beam produced at the ISOLDE radioactive beam facility, is reported.