A new in-gas-laser ionization and spectroscopy laboratory for off-line studies at KU Leuven

Abstract

a b s t r a c tThe in-gas laser ionization and spectroscopy (IGLIS) technique is used to produce and to investigate short-lived radioactive isotopes at on-line ion beam facilities. In this technique, the nuclear reaction products recoiling out of a thin target are thermalized and neutralized in a high-pressure noble gas, resonantly ionized by the laser beams in a two-step process, and then extracted from the ion source to be finally accelerated and mass separated. Resonant ionization of radioactive species in the supersonic gas jet ensures very high spectral resolution because of essential reduction of broadening mechanisms. To obtain the maximum efficiency and the best spectral resolution, properties of the supersonic jet and the laser beams must be optimized. To perform these studies a new off-line IGLIS laboratory, including a new high-repetition-rate laser system and a dedicated off-line mass separator, has been commissioned. In this article, the specifications of the different components necessary to achieve optimum conditions in laser-spectroscopy studies of radioactive beams using IGLIS are discussed and the results of simulations are presented.

Development of a low-energy radioactive ion beam facility for the MARA separator

“…The bend removes the requirement for the laser beam to pass through all the ion guides thus allowing for smaller diameter ion guides and hence smaller diameter differential pumping ports. In contrast to the concept presented in [23] the gas cell and the MARA-LEB vacuum chamber will be on high-voltage with the ions accelerated towards ground potential.…”

“…The ion optics are under development and will be presented elsewhere. The concept is similar to that presented in [23] with the major difference being the use of a 90 • -bent first ion guide, due to space restrictions, and two, instead of one, electrodes at the extraction point for reaching the desired acceleration voltage. Sufficient inner diameter of the first ion guide will allow for a laser beam with the same diameter as the gas jet to pass through it and overlap with the jet at the exit of the gas cell.…”

Characterization of Supersonic Gas Jets for High-Resolution Laser Ionization Spectroscopy of Heavy Elements

“…A full description of the IGLIS laboratory is given in Ref. [46]. Here, only the details related to the PLIF experiments are described thoroughly with a schematic layout of a PLIF spectroscopy setup shown in Fig.…”

“…In this paper, we present the first application of atomic PLIF spectroscopy for the characterization of the local flow parameters (velocity, temperature, and relative density) of supersonic jets formed by de Laval nozzles. These studies were performed at the recently commissioned IGLIS laboratory [46], where PLIF spectroscopy, utilizing the fluorescence light emitted by the stable 63;65 Cu isotopes seeded into an argon flow, was applied. After a description of the IGLIS laboratory with a dedicated PLIF spectroscopy setup, the PLIF spectroscopy studies are validated using supersonic free jets.…”

Status and development of the MARA low-energy branch

“…A small-volume buffer gas cell has been built to stop, thermalise and, depending on experimental requirements, neutralise the recoils exiting from the MARA separator. The gas cell design is based on a gas cell built for the HELIOS facility at KU Leuven [7] and is shown in Figure 1 (a). The gas cell inherits concepts from the dual-chamber design [8] and has separate regions for stopping of recoils and laser ionisation.…”