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A study on the systematic of the atomic ionization potentials for both, the lanthanide and actinide elements have been performed. The existing experimental basis, predominantly relying on results from resonance ionization spectroscopy, has been extended by novel laser spectroscopic investigations on the elements Au, Dy, Pr and Pa. Conclusive results of suitable precision for the ionization potentials could be obtained except for Pa, due to the complexity of its atomic spectrum. Nevertheless, a consistent interpretation of the observed trends for the ionization potentials of lanthanides and actinides was attempted. The series of lanthanides depicts the two well-known, completely smooth, linear trends above and below half-shell closure, from which an expectation value for the missing ionization potential of the all radioactive element promethium of IP Pm= 44985(140) cm −1 was derived. In contrast, the lighter members of the actinide series below the half-filled shell exhibit a significant deviation from predictions, which are ascribed dominantly to relativistic influences affecting the energetic position of the multitude of low-lying configurations. With the assumption of removal of a 6d electron during the ionization process agreement between theory and experiment and a smooth, even though not linear behavior, is obtained also in this region of the Periodic Table. This new interpretation could help to better predict similar trends and systematics for elements heavier than the actinides. Particularly relevant in this respect are the super-heavy elements, which are produced only in minuscule atom numbers and thus were not accessible for any atomic physics study yet.

An ISOLDE-type hot-cavity laser ion source based on high-repetition-rate Ti:Sapphire lasers has been set up at the Holifield radioactive ion beam facility. To assess the feasibility of the all-solid-state laser system for applications at advanced radioactive ion beam facilities, spectroscopy and performance tests have been conducted with this source. The results of recent studies on excitation schemes, source efficiency, beam emittance and ion time structure are presented.

A combined structure consisting of a laser ion source and a linear Paul trap (LIST) has been designed to produce radioactive ion beams of high purity and optimal temporal and spacial brilliance at on-line isotope separator (ISOL) facilities. The functionality of the LIST was experimentally demonstrated in off-line tests using the RISIKO off-line mass separator together with an all solid state Ti:sapphire laser system at the University of Mainz. Two different ion trap designs were tested extracting the performance of these devices regarding ionization efficiency and selectivity as well as time structure and transverse emittance of the produced ion beam. The results of these measurements are presented together with an outlook on the next steps towards the first on-line application of the LIST.

Ion beam purity is of crucial importance to many basic and applied studies in nuclear science. Selective photodetachment has been proposed to suppress unwanted species in negative ion beams while preserving the intensity of the species of interest. A highly efficient technique based on photodetachment in a gas-filled radio frequency quadrupole ion cooler has been demonstrated. In off-line experiments with stable ions, up to 10(4) times suppression of the isobar contaminants in a number of interesting radioactive negative ion beams has been demonstrated. For selected species, this technique promises new experimental possibilities in studies on exotic nuclei, accelerator mass spectrometry, and fundamental properties of negative atomic and molecular ions.

International audience; In-source resonance ionization spectroscopy was used to identify an efficient and selective three step excitation/ionization scheme of thorium, suitable for titanium:sapphire (Ti:sa) lasers. The measurements were carried out in preparation of laser spectroscopic investigations for an identification of the low-lying 229 m Th isomer predicted at 7.6 ± 0.5 eV above the nuclear ground state. Using a sample of 232 Th, a multitude of optical transitions leading to over 20 previously unknown intermediate states of even parity as well as numerous high-lying odd parity auto-ionizing states were identified. Level energies were determined with an accuracy of 0.06 cm −1 for intermediate and 0.15 cm −1 for auto-ionizing states. Using different excitation pathways an assignment of total angular momenta for several energy levels was possible. One particularly efficient ionization scheme of thorium, exhibiting saturation in all three optical transitions, was studied in detail. For all three levels in this scheme, the isotope shifts of the isotopes 228 Th, 229 Th, and 230 Th relative to 232 Th were measured. An overall efficiency including ionization, transport and detection of 0.6 % was determined, which was predominantly limited by the transmission of the mass spectrometer ion optics.

International audience; The depopulation of excited states in beams of negatively charged carbon and silicon ions was demonstrated using collisional detachment and laser photodetachment in a radio frequency quadrupole ion guide filled with helium. The high lying, loosely bound 2 D excited state in C − was completely depleted through collisional detachment alone, which was quantitatively determined within 6%. For Si − the combined signal from the population in the 2 P and 2 D excited states was only partly depleted through collisions in the cooler. The loosely bound 2 P state was likely to be completely depopulated and the more tightly bound 2 D state was partly depopulated through collisions. 98(2)% of the remaining 2 D population was removed by photodetachment in the cooler using less than 2 W laser power. The total reduction of the excited population in Si −, including collisional detachment and photodetachment, was estimated to be 99(1)%. Employing this novel technique to produce a pure ground state negative ion beam offers possibilities to enhance selectivity, as well as accuracy, in high precision experiments on atomic as well as molecular negative ions.

International audience; SPIRAL2 is the new project under construction at GANIL to produce radioactive ion beams and in particular neutron rich ion beams. For the past 10 yr SPIRAL1 at GANIL has been delivering accelerated radioactive ion beams of gases. Both facilities now need to extend the range of radioactive ion beams produced to condensable elements. For that purpose, a resonant ionization laser ion source, funded by the French Research National Agency, is under development at GANIL, in collaboration with IPN Orsay, University of Mainz Germany and TRIUMF, Vancouver Canada . A description of this project called GISELE GANIL Ion Source using Electron Laser Excitation is presented.

Laser ion sources based on resonant excitation and ionization of atoms are well-established tools for selective and efficient production of radioactive ion beams. Recent developments are focused on the use of the state-of-the-art all solid-state laser systems. To date, 35 elements of the periodic table are available from laser ion sources based on tunable Ti:sapphire lasers. Recent progress in this field regarding the establishment of suitable optical excitation schemes for Ti:sapphire lasers are reported.

The time spreads of Mn ions produced by three-photon resonant ionization in a hot-cavity laser ion source are measured. A one-dimensional ion-transport model is developed to simulate the observed ion time structures. Assuming ions are generated with a Maxwellian velocity distribution and are guided by an axial electric field, the predictions of the model agree reasonably well with the experimental data and suggest that the ions are radially confined in the ion source and a substantial fraction of the ions in the transport tube are extracted.

On‐line production facilities for radioactive isotopes nowadays heavily rely on resonance ionization laser ion sources due to their demonstrated unsurpassed efficiency and elemental selectivity. Powerful high repetition rate tunable pulsed dye or Ti:sapphire lasers can be used for this purpose. To counteract limitations of short pulse pump lasers, as needed for dye laser pumping, i.e. copper vapor lasers, which include high maintenance and nevertheless often only imperfect reliability, an all‐solid‐state Nd:YAG pumped Ti:sapphire laser system has been constructed. This could complement or even replace dye laser systems, eliminating their disadvantages but on the other hand introduce shortcomings on the side of the available wavelength range. Pros and cons of these developments will be discussed.

A resonant ionization laser ion source based on all‐solid‐state, tunable Ti:Sapphire lasers is being developed for the production of pure radioactive ion beams. It consists of a hot‐cavity ion source and three pulsed Ti:Sapphire lasers operating at a 10 kHz pulse repetition rate. Spectroscopic studies are being conducted to develop ionization schemes that lead to ionizing an excited atom through an auto‐ionization or a Rydberg state for numerous elements of interest. Three‐photon resonant ionization of 12 elements has been recently demonstrated. The overall efficiency of the laser ion source measured for some of these elements ranges from 1 to 40%. The results indicate that Ti:Sapphire lasers could be well suited for laser ion source applications. The time structures of the ions produced by the pulsed lasers are investigated. The information may help to improve the laser ion source performance.

The inception of laser resonance ionization spectroscopy and its application as a resonant ionization laser ion source (RILIS) took place merely 20 years ago with pulsed dye lasers [1–5]. By now next generation radioactive ion beam (RIB) facilities are being planned or built. Understanding and considering the unique RILIS requirements in the layout of next generation RIB facilities will allow for cost‐effective implementation of this versatile ion source. This discussion touches on laser beam transport and RILIS requirements not necessarily obvious to experts in conventional ion sources.

The TRIUMF Resonant Ionization Laser Ion Source (RILIS) for radioactive ion beam production is presented, with target ion source, laser beam transport, laser system and operation. In this context aspects of titanium sapphire (TiSa) laser based RILIS and facility requirements are discussed and results from the first years of TRILIS RIB delivery are given.

This report describes the efforts made to develop a resonant-ionization laser ion source based on tunable Ti:sapphire lasers for nuclear physics and astrophysics research at Holifield Radioactive Ion Beam Facility. Three Ti:sapphire lasers have been upgraded with individual pump lasers to eliminate laser power losses due to synchronization delays. Ionization schemes for 14 elements have been obtained. Off-line studies show that the overall efficiency of the laser ion source can be as high as 40%. TaC surface coatings have been investigated for minimizing surface and bulk trapping of the atoms of interest.

The improvement in the performance of a conventional laser ion source in the laser ion source and trap (LIST) project is presented, which envisages installation of a repeller electrode and a linear Paul trap/ion guide structure. This approach promises highest isobaric purity and optimum temporal and spatial control of the radioactive ion beam produced at an online isotope separator facility. The functionality of the LIST was explored at the offline test separators of University of Mainz (UMz) and ISOLDE/CERN, using the UMz solid state laser system. Ionization efficiency and selectivity as well as time structure and transversal emittance of the produced ion beam was determined. Next step after complete characterization is the construction and installation of the radiation-hard final trap structure and its first online application.