Commissioning of the S3 Low Energy Branch at GANIL-SPIRAL2

by Andres Felipe Lopez (2^nd year PhD student)

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 MHz), high repetition rate (∼kHz) and high power (∼ hundreds of μJ per pulse), which 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 (<1000 isotopes per second) while maintaining an excellent spectral resolution ([2]). Following the laser ionization, the Radioactive Ion Beams (RIBs) can be sent to a number of different experimental setups, such as the SEASON decay station [3], IDEAS3 tape station, or a MR-TOF-MS setup referred as PILGRIM [4].

In the coming years transport to the DESIR facility [5] will also be possible, enabling further high precision studies. After an off-line commissioning at Laboratoire de Physique Corpusculaire (LPC) de Caen [6, 7], the S3-LEB setup was moved and 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 experiment 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 seminar I will present the recommissioning results going deeper into PILGRIM performance. Furthermore, the different laser systems currently under preparation at ALTISA laboratory will be shown, as well as laser spectroscopy of stable dysprosium isotopes in an atomic beam unit conducted at GISELE laboratory.

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] E. Rey-herme, PhD thesis. Universit´e Paris-Saclay (2023)
[4] P. Chauveau, et al., Nucl. Instrum. Meth. B 376 (2016) 211–215.
[5] Thomas, B. Blank, French-Japanese symposium, Wako, Japan. (2011)
[6] A. Ajayakumar, et al., Nucl. Instrum. Meth. B 539, 102 (2023)
[7] J. Romans, et al., Nucl. Instrum. Meth. B 536, 72 (2023)