Upgrade of the resonance ionization laser ion source at ISOLDE on-line isotope separation facility: New lasers and new ion beams

Abstract

The resonance ionization laser ion source (RILIS) produces beams for the majority of experiments at the ISOLDE on-line isotope separator. A substantial improvement in RILIS performance has been achieved through a series of upgrade steps: replacement of the copper vapor lasers by a Nd:YAG laser; replacement of the old homemade dye lasers by new commercial dye lasers; installation of a complementary Ti:Sapphire laser system. The combined dye and Ti:Sapphire laser system with harmonics is capable of generating beams at any wavelength in the range of 210-950 nm. In total, isotopes of 31 different elements have been selectively laser-ionized and separated at ISOLDE, including recently developed beams of samarium, praseodymium, polonium, and astatine.

β−decay of65Mn to65Fe

“…The reaction products diffused out of the target matrix, were ionized by the selective resonant ionization laser-ion source RILIS [26], and accelerated to 30 kV. The A = 65 ions were then mass separated by the General Purpose Separator (GPS) [27] and implanted into a thin aluminium foil in the center of the experimental setup.…”

Plumbing Neutron Stars to New Depths with the Binding Energy of the Exotic NuclideZn82

“…This technique reduced isobaric contamination, which would result from direct spallation reactions. In addition, a highly selective three-step laser excitation [22] to ionize zinc isotopes was applied as well as a temperature-controlled quartz transfer line [23] that prevented the copious surface-ionized rubidium isotopes from drowning the zinc ion beam. Despite these state-of-the-art precautions, over 6000 ions per second of 82 Rb were still present in the 82 Zn beam delivered to ISOLTRAP-to be compared to just a few ions of interest.…”

Production and investigation of heavy neutron rich nuclei

“…The ion beams available at FLNR fully satisfy the requirements for this project: the ions that can be used are quite different depending on the problem to be solvedfrom 16,18 O to 238 U, beam energies 4.5 -9 MeV/nucleon (slightly above the Coulomb barrier) and beam intensity up to 10 13 pps are accessible with a beam size at the target of 3-10 mm and beam emittance of 20·π·mm·mrad. Different heavy targets, including those of actinides, are expected to be used.…”

“…Such a scheme allows choosing more effective optical transitions to increase the yield of resonance-ionized ions, although the use of two-step ionization scheme is as not excluded. Dye laser systems pumped by second and third harmonics of Nd:YAG can provide tuning in a broad spectral range: from near UV to near IR [16]. The generation of a Ti:Sapphire lasers, shifted to the red and infrared edge of the spectrum (680-960 nm), can be also used as complementary to that of the dye lasers.…”

“…Although there are many observed spectral lines, as the atomic spectra information is not yet complete: most of the transitions are not assigned [16][17][18][19] and the atomic strengths are not known. Nevertheless several of the possible RIS scheme for Os have been previously studied [20,21].…”