Orateur
Description
Laser spectroscopy for studying the ground- and isomeric-state properties of exotic nuclei has established itself as a versatile and powerful tool, capable of providing access to nuclear-model-independent data such as mean-square charge radii, magnetic dipole and electric quadrupole moments, and nuclear spins [1]. For resonance ionization spectroscopy, a critical set of conditions is having tunable laser sources with narrow bandwidth (100-200 MHz), high repetition rate (10 kHz) and high power (∼ hundreds of μJ average energy per pulse), which assure high efficiency and allow measuring the hyperfine structure and isotope shift along isotopic chains.
The Low-Energy-Branch (LEB) coupled to the Super Separator Spectrometer (S3) facility at GANIL-SPIRAL2 will enable high-resolution in-gas-jet laser ionization spectroscopy of fusion-evaporation products, overcoming the present experimental constraints of low production while maintaining an excellent spectral resolution ([2, 3, 4]). Following resonance laser ionization, the highly pure radioactive ion beams can be sent to a number of different experimental setups, such as the SEASON decay station [5], a MR-TOF-MS setup referred to PILGRIM [6]; or be transported to the DESIR facility [7] in the coming years enabling further high precision studies.
The setup has been installed at the focal plane of S3 and new tests have been performed to ensure its performance in preparation for the first experiments with S3 beams. The first foreseen fusion-evaporation reaction during the on-line commissioning will give the opportunity to obtain nuclear and atomic information of neutron-deficient isotopes around erbium and towards the N = 82 shell closure.
In this contribution I will present results of recent off-line experiments performed with S3-LEB in its current location, including the trapping and mass selection of ions with PILGRIM. Furthermore, the different laser systems currently under preparation in the new laser laboratory ALTISA will be shown, as well as laser spectroscopy results of stable dysprosium and gadolinium isotopes in an atomic beam unit, in preparation of the on-line commissioning.
References
[1] X.F. Yang, et al., Prog. Part. Nucl. Phys. 129 (2023).
[2] R. Ferrer et al., Nucl. Instrum. Meth. B 317 (2013) 570–581.
[3] A. Ajayakumar, et al., Nucl. Instrum. Meth. B 539, 102 (2023).
[4] J. Romans, et al., Nucl. Instrum. Meth. B 536, 72 (2023).
[5] E. Rey-herme, PhD thesis. Universit´e Paris-Saclay (2023).
[6] P. Chauveau, et al., Nucl. Instrum. Meth. B 376 (2016) 211–215.
[7] Thomas, B. Blank, French-Japanese sym. on nuclear structure, (2011).