The Multi Ion Reflection Apparatus for Collinear Laser Spectroscopy

by Stephan Malbrunot (TRIUMF, Vancouver, Canada / University of Toronto, Canada / CERN, ISOLDE, Geneva, Switzerland)

Wednesday 8 Jun 2022, 16:00 → 17:00 Europe/Vienna

This SMI-Seminar will be held online as Webinar.
https://oeaw-ac-at.zoom.us/j/92244066405?pwd=U0c2V0lFQndTVS9VOGxPbnA1Y05tUT09

Abstract:

Exotic, short-lived radionuclides serve as intriguing probes for a diverse spectrum of physics questions ranging from nuclear astrophysics to fundamental symmetries. In particular, unraveling the complex nuclear many-body problem from first principles remains a formidable task for contemporary nuclear physics.
In recent years, significant experimental and theoretical effort has been dedicated to the study of electromagnetic properties in atomic nuclei. A benchmark by recent laser-spectroscopy work at COLLPAS/ISOLDE, for instance, establishes a theoretical accuracy of ∼1% achieved by modern nuclear models in their description of nuclear charge radii in Nickel (Ni) isotopes [1].
However, in order to test nuclear theory very far away from stability, i.e. in radionuclides with ‘extreme’ proton-to-neutron ratios, new methods with increased experimental sensitivity have the be envisioned. To this end, we have developed the Multi Ion Reflection Apparatus for Collinear Laser Spectroscopy (MIRACLS), which connects the successful tradition of collinear laser spectroscopy (CLS) with ion-trap technology [2]. Our novel approach exploits a Multi-Reflection Time-of-Fight (MR-ToF) device in which ions bounce back and forth between two electrostatic mirrors. Hence, the trapped ions are probed by the spectroscopy laser during each revolution inside the MR-ToF device compared to a single passage through a laser-ion interaction region in conventional CLS. Thus, the MIRACLS approach enhances the sensitivity of CLS by a factor of 30-700.
While our initial work is focused on highly sensitive CLS for nuclear structure research, the novel experimental techniques developed within MIRACLS additionally open opportunities for atomic-physics studies with negative ions or for searches for new physics beyond the standard model of particle physics in radioactive molecules. The later have recently been identified as unexplored, yet highly sensitive probes for fundamental physics such as hitherto undiscovered permanent electric dipole moments [3].
After discussing the Ni results at COLLAPS, this talk will present the MIRACLS concept, its successful application in a proof-of-principle experiment, as well as its ongoing experimental efforts for laser spectroscopy of radionuclides.

[1] S. Malbrunot-Ettenauer et al., Phys. Rev. Lett. 128, 022502 (2022)
[2] S. Sels et al., Nucl. Instr. Meth. B 463, 310 (2020)
      V. Lagagki et al., Nucl. Instr. Meth. A 1014, 165663 (2021)
      S. Sels et al., submitted to Physical Review Research
[3] R. F. Garcia Ruiz et al., Nature 581, 396–400 (2020)