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HK: Fachverband Physik der Hadronen und Kerne

HK 13: Focus Session I: New Results on Nuclear Structure at Shell Closures

HK 13.1: Hauptvortrag

Dienstag, 12. März 2024, 14:00–14:30, HBR 14: HS 1

First laser spectroscopy measurements of ⁵³Ca and the prospects for measuring ⁵⁴Ca — •Tim Lellinger for the COLLAPS collaboration — EP-SME-IS, CERN — TU-Darmstadt

Over a decade ago, the first experimental evidence for the N=32 sub shell closure in the calcium isotopic chain emerged [1,2]. Subsequent experimental and theoretical investigations have confirmed this finding. However, in laser spectroscopy measurements extending up to ⁵²Ca (N=32), no indications of this shell gap were apparent [3]. Crossing the shell gap with laser spectroscopy setups has proved difficult due to the simultaneous requirement of a sensitivity of approximately 10 ions/s and a measurement uncertainty on the order of MHz.

This contribution presents the first laser spectroscopy measurements of ⁵³Ca, facilitated by an extension of the collinear laser spectroscopy technique employed at the COLLAPS setup at ISOLDE/CERN. This technique, termed as radioactive detection after optical pumping and state selective charge exchange (ROC), combines the high sensitivity of a particle detection scheme with the high resolution of low-power, continuous wave lasers utilized in a collinear geometry. The methodology of this technique will be explained, followed by the presentation and discussion of preliminary values for the charge radius and magnetic dipole moment of ⁵³Ca in the context of the robustness of the N=32 sub shell closure, as well as the prospects to measure ⁵⁴Ca.

[1] Wienholtz, F. et al. Nature vol. 498, 346-349 (2013)

[2] Steppenbeck, D. et al. Nature vol. 502, 207-210 (2013)

[3] R.F. Garcia Ruiz et al, Nature Physics vol. 12, 594-598 (2016)

Keywords: laser spectroscopy; nuclear shell closure; magic numbers