In November 2023, the RIALTO experimental setup has enabled the production of silver (Ag) and gallium (Ga) radioactive ion beams measured at the TETRA device during the N-RI-22 experiment. RIALTO consists of three dye lasers and two Nd:YAG lasers, one of which dedicated to pumping. We can therefore generate 4 different wavelengths.
Ion production is obtained by laser resonant ionization: silver ions are produced in a 3 step-3 colour scheme, while gallium ions are produced in a 2 step-2 colour scheme. Figure 1 illustrates the two ionization schemes. The first two UV stages are obtained by doubling the frequencies of the yellow and red lasers. Thanks to a common ionization wavelength (the YAG laser), the system can easily switch between Ag and Ga elements in just a few minutes.
The laser beams, sent collinearly through a 3 mm diameter tube at a distance of 18 meters, benefit from a position control system to maintain their geometric stability. This system prevents any deviation of the beams in the ionization tube and enables them to be adjusted in real time.
Figure 2 shows a γ spectrum of 123Ag measured on the TETRA decay station, with and without the use of the laser.
