Recent developments for laser spectroscopy at the Low-Energy Branch of SPIRAL2-S3

par Valentin Marchand (Nucléaire - SDF)

jeudi 5 mars 2026, 14:00 → 15:00 Europe/Paris

100/0-A018 - Salle Library (IJCLab)

The GANIL accelerator complex in Caen, France recently commissioned a new superconducting linear accelerator as part of the SPIRAL2 facility. This facility enables the production of heavy and super-heavy radionuclides via fusion-evaporation at the entrance of the Super Separator Spectrometer (S³) experimental area. There, the secondary beam undergoes several stages of mass separation and focusing to be finally delivered to a focal plane experiment [1]. Located at the S³ focal point, the S³ Low Energy Branch (S³-LEB) is a low-energy experiment dedicated to the study of nuclides using the In-Gas Laser Ionization Spectroscopy (IGLIS) technique, as well as decay spectroscopy and mass spectrometry [2]. These techniques allow to probe the structure of exotic nuclei, providing access to properties such as the charge radius, the spin and the magnetic and quadrupole moments.

The current S³-LEB gas cell allows only the study of nuclides with a certain half-life. In order to increase the experimental possibilities of the setup, the Fast Radioactive Ion Extraction and Neutralization Device for S³ (FRIENDS³) project aims to design a new gas cell. The latter needs to minimize the extraction time, maximize the extraction and neutralization efficiency while minimizing the neutralization time. The FRIENDS³ setup has been designed and constructed, and is currently in the test phase at GANIL.

During the first part of the seminar I will introduce the S³-LEB and FRIENDS³ setups as well as the current status their commissionning. Thereafter, I will present the recent progress regarding our laser setup. Currently, our narrowband Injection-Locked Ti:sa Cavity (ILC) is seeded by an External Cavity Diode Laser (ECDL), used to set the narrowband frequency. However, in response to our needs for a wider tunable wavelength range, a home-made continuous wave Ti:sa laser is under development. To conclude, I will present preliminary results of a proof-of-principle laser-spectroscopy experiment of stable Dysprosium performed with the continuous-wave Ti:sa.

[1] A. Drouart, J.A. Nolen, and H. Savajols. “The Super Separator Spectrometer (S³) for the SPIRAL2 facility”, Journal of Physics: Conference Series 1643, 012032. (2020)
[2] A. Ajayakumar et al. “In-gas-jet laser spectroscopy with S³-LEB”, Nucl. Instrum. Meth. B 539, 102-107 (2023)