Charge radii, moments, and masses of mercury isotopes across the N = 126 shell closure
Not Available
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Engineering topics
Wendt, K.
Publications and source records attributed to Wendt, K..
Resonant ionization spectroscopy of autoionizing Rydberg states in cobalt and redetermination of its ionization potential
We obtained multi-step resonance ionization spectroscopy of cobalt using a hot-cavity laser ion source and three Ti:Sapphire lasers. Furthermore, the photoionization spectra revealed members of five new autoionizing Rydberg series that originate from three different lower levels of 3d 7 4s5s h 4 F 9/2 , 3d 7 4s4d f 4 G 11/2 , and 3d 7 4s4d f 4 H 13/2 and converge to the first four excited states of singly ionized Co. Our analyses of the Rydberg series yield 63564.689 0.036 cm -1 as the first ionization potential of Co, which is an order of magnitude more accurate than the previous estimation. Using a three-step resonance ionization scheme that employs an autoinizing Rydberg state in the last transition, we obtained an overall ionization efficiency of about 18% for Co.
74 ATOMIC AND MOLECULAR PHYSICS↗
High efficiency resonance ionization of palladium with Ti:sapphire lasers
Here, we present the development and testing of highly efficient excitation schemes for resonance ionization of palladium. To achieve the highest ionization efficiencies, a high-power, high repetition rate Ti:sapphire laser system was used and 2-step, 3-step and 4-step schemes were investigated and compared. Starting from different excited steps, the frequencies of the final ionization steps were tuned across the full accessible spectral range of the laser system, revealing several autoionizing Rydberg series, which converge towards the energetically higher lying state 4d 9 2 D 3/2 of the Pd + ion ground state configuration. Through proper choice of these excitation steps, we developed a highly efficient, fully resonant 3-step excitation scheme, which lead to overall efficiencies of 54.3(1.4)% and 59.7(2.1)%, measured at two independent mass separator setups. Lastly, to our knowledge, these are presently the highest efficiency values ever achieved with a resonance ionization laser ion source.
74 ATOMIC AND MOLECULAR PHYSICS↗
Optimization of a hot-cavity type resonant ionization laser ion source
Resonant Ionization Laser Ion Source (RILIS) is nowadays an important technique in many Radioactive Ion Beam (RIB) facilities for its reliability and ability to ionize efficiently and element selectively. Grand Accélérateur National d’Ions Lourds (GANIL) Ion Source using Electron Laser Excitation (GISELE) is an off-line test bench for RILIS developed to study a fully operational resonant laser ion source at GANIL facility. The ion source body has been designed as a modular system to investigate different experimental approaches by varying the design parameters, to develop the future on-line laser ion source. The aim of this project is to determine the best technical solution which combines high selectivity and ionization efficiency with small ion beam emittance and stable long term operation. Latest results concerning emittance and time profile development as a function of the temperature for different ion source versions will be presented.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Three-photon resonance ionization of atomic Mn in a hot-cavity laser ion source using Ti:sapphire lasers
Three-photon resonance ionization of atomic manganese (Mn) in a hot-cavity ion source using Ti:sapphire lasers has been demonstrated. Three-step ionization schemes employing different intermediate levels and Rydberg or autoionizing (AI) states in the final ionization step are established. Strong AI resonances were observed via the 3d 5 4s5s f 6 S 5/2 level at 49 415.35 cm -1 , while Rydberg transitions were reached from the 3d 5 4s4d e 6 D 9/2,7/2,5/2 levels at around 47 210 cm -1 . Analyses of the strong Rydberg transitions associated with the 3d 5 4s4d e 6 D 7/2 lower level indicate that they belong to the dipole-allowed 4d→nf 6 F° 9/2,7/2,5/2 series converging to the 3d 5 4s 7 S 3 ground state of Mn II. From this series, an ionization potential of 59 959.56 ± 0.01 cm -1 is obtained for Mn. At high ion source temperatures the semi-forbidden 4d→nf 8 F° 9/2,7/2,5/2 series was also observed. The overall ionization efficiency for Mn has been measured to be about 0.9% when using the strong AI transition in the third excitation step and 0.3% when employing an intense Rydberg transition. Ultimately, our experimental data indicate that the ionization efficiency was limited by the interaction of Mn atoms with ion source materials at high temperatures.
74 ATOMIC AND MOLECULAR PHYSICS↗
Progress of resonant ionization laser ion source development at GANIL
SPIRAL2 (Système de Production d’Ions Radioactifs Accélérés en Ligne) is a research facility under construction at GANIL (Grand Accélérateur National d’Ions Lourds) for the production of radioactive ion beams by isotope separation on-line methods and low-energy in-flight techniques. A resonant ionization laser ion source will be one of the main techniques to produce the radioactive ion beams. GISELE (GANIL Ion Source using Electron Laser Excitation) is a test bench developed to study a fully operational laser ion source available for Day 1 operations at SPIRAL2 Phase 2. The aim of this project is to find the best technical solution which combines high selectivity and ionization efficiency with small ion beam emittance and stable long term operation. Latest results about the new ion source geometry will be presented.
43 PARTICLE ACCELERATORS↗
Resonant three-Photon Ionization Spectroscopy of Atomic Fe
Laser spectroscopic investigations on high-lying states around the ionization potential in the atomic spectrum of Fe have been carried out for development of a practical three-step resonance ionization scheme accessible by Ti:Sapphire lasers. A hot cavity laser ion source typically used at on-line radioactive ion beam production facilities was employed in this work. Ionization schemes employing high-lying Rydberg and autoionizing states populated by three-photon excitations were established. Five new Rydberg and autoionizing Rydberg series converging to the ground and to the first four excited states of Fe II are reported. Analyses of the Rydberg series yield the value 63737.686 ± 0.068 cm-1 for the ionization potential of iron.
Liu, Yuan↗
Integrated Recycling Test Fuel Fabrication
The Integrated Recycling Test is a collaborative irradiation test that will electrochemically recycle used light water reactor fuel into metallic fuel feedstock. The feedstock will be fabricated into a metallic fast reactor type fuel that will be irradiation tested in a drop in capsule test in the Advanced Test Reactor on the Idaho National Laboratory site. This paper will summarize the fuel fabrication activities and design efforts. Casting development will include developing a casting process and system. The closure welding system will be based on the gas tungsten arc burst welding process. The settler/bonder system has been designed to be a simple system which provides heating and controllable impact energy to ensure wetting between the fuel and cladding. The final major pieces of equipment to be designed are the weld and sodium bond inspection system. Both x-radiography and ultrasonic inspection techniques have been examine experimentally and found to be feasible, however the final remote system has not been designed. Conceptual designs for radiography and an ultrasonic system have been made.
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
Beam Purification by Photodetachment
Ion beam purity is of crucial importance to many basic and applied studies. 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 104 times suppression of the isobar contaminants in a number of interesting radioactive negative ion beams has been demonstrated. For selected species, this technique promises experimental possibilities in studies on exotic nuclei, accelerator mass spectrometry, and fundamental properties of negative atomic and molecular ions.
Liu, Yuan↗
Laser Ion Source Development at HRIBF
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 HRIBF. 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.
Liu, Yuan↗