In November 2023, the RIALTO experimental system on IJCLab's ALTO platform enabled the production of radioactive ion beams of silver (Ag) for the first time and gallium (Ga), measured on the TETRA device over the course of the N-RI-22 experiment. RIALTO consists of three dye lasers and two Nd:YAG lasers, one of which is dedicated to optical pumping. We can therefore generate 4 different wavelengths.
The production of ions is carried out by resonant laser ionization: silver ions are produced via a 3-stage-3-color scheme, while those of gallium follow a 2-stage-2-color process. The first two stages in the ultraviolet are obtained by doubling the frequencies of the yellow and red lasers. Using a common ionization wavelength (the YAG laser), the system can easily alternate between Ag and Ga elements in just a few minutes.
The laser beams are sent together in a 3 mm diameter tube located at a distance of 18 meters. They benefit from a position control system to maintain their geometric stability. This system prevents any deviation of the beams in the ionization tube and allows their adjustment in real time. A gamma spectrum of the radioactive decay of silver-123 was recorded and the Ag peaks only appear when lasers are fired into the source.