[en] Laser ion acceleration induced by high-power laser systems is nowadays an important research subject due to the large potential range of applications it could satisfy. Most of the available high-power laser facilities deliver only a few laser pulses per hour. The new facilities under development will operate at higher repetition rates (up to 10 Hz). Conventional target technologies (solid targets) and acceleration mechanisms (Target Normal Sheath Acceleration TNSA) used so far in laser-based ion acceleration are difficult to implement at high repetition rate. New ion acceleration mechanisms such as Collisionless Shock-wave Acceleration (CSA) using high density gas jets represent therefore a promising alternative. Dense gas jet targets show several advantages such as constant refresh and negligible debris production. However, full comprehension of the fluid dynamics involved in the gas jet target production is fundamental for its optimization, and at present precise data is scarce. An ongoing study of design and optimization of supersonic gas jet nozzles for laser-based ion acceleration is presented. (authors)

[en] For most applications of laser driven ion beams, a well-characterized high repetition rate intense ion beam with low divergence and a controllable energy spectrum is needed. High power laser-solid targets interactions are usually used, in which the main acceleration mechanism is the so-called Target Normal Sheath Acceleration (TNSA). Changing solid targets for overcritical gas jet targets has given interesting results in theoretical simulations and these later have several technical advantages for high repetition rate lasers. In this work protons and helium ions are accelerated from a near-critical supersonic gas jet. The production of such targets is very challenging for near infrared lasers. We present recent results concerning the design and characterization of supersonic gas nozzles able to deliver such high densities and the first results obtained during the first experiment on PICO2000 facility at LULI. We succeeded to accelerate ions up to several MeV with a H-2 and He gas jet target. The number of accelerated ions is comparable to the one usually obtained with solid targets. (authors)

[en] Computational fluid dynamics simulations are performed to design gas nozzles, associated with a 1000 bars backing pressure system, capable of generating supersonic gas jet targets with densities close to the critical density for 1053 nm laser radiation (10²¹) cm^-3). Such targets should be suitable for laser-driven ion acceleration at a high repetition rate. The simulation results are compared to the density profiles measured by interferometry, and characterization of the gas jet dynamics is performed using strioscopy. Proton beams with maximum energies up to 2 MeV have been produced from diatomic hydrogen gas jet targets in a first experiment. (authors)

[en] Highlights: • For Spiral 1, a febiad ion source has been connected to a graphite target. • For Spiral 2, an oven made with a carbon resistor is under development. • We made some measurement of effusion in the Spiral 2 target. • A laser ion source is under construction. -- Abstract: The GANIL facility (Caen, France) is dedicated to the acceleration of heavy ion beams including radioactive beams produced by the Isotope Separation On-Line (ISOL) method at the SPIRAL1 facility. To extend the range of radioactive ion beams available at GANIL, using the ISOL method two projects are underway: SPIRAL1 upgrade and the construction of SPIRAL2. For SPIRAL1, a new target ion source system (TISS) using the VADIS FEBIAD ion source coupled to the SPIRAL1 carbon target will be tested on-line by the end of 2013 and installed in the cave of SPIRAL1 for operation in 2015. The SPIRAL2 project is under construction and is being design for using different production methods as fission, fusion or spallation reactions to cover a large area of the chart of nuclei. It will produce among others neutron rich beams obtained by the fission of uranium induced by fast neutrons. The production target made from uranium carbide and heated at 2000 °C will be associated with several types of ion sources. Developments currently in progress at GANIL for each of these projects are presented

[en] For most laser-driven ion acceleration applications, a well-characterized intense ion beam with a low divergence and a controllable energy spectrum produced at a high repetition rate is needed. Gas-jet targets have given promising results in simulations, and they have several technical advantages for high-repetition-rate lasers. In this work, we report on proton acceleration to energies up to 6 MeV using a supersonic H₂ gas-jet target at the LULI PICO2000 laser facility. The experimental results are compared with the plasma hydrodynamics and the particle-in-cell simulations to identify the acceleration mechanisms at play. (authors)

[en] The Resonance Ionization Laser Ion Source (RILIS) has emerged as an important technique in many Radioactive Ion Beam (RIB) facilities for its reliability, and ability to ionize target elements efficiently and element selectively. GISELE is an off-line RILIS test bench to study the implementation of an on-line laser ion source at the GANIL separator facility. 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. The ion source geometry was tested in several configurations in order to find a solution with optimal ionization efficiency and beam emittance. Furthermore, a low work function material was tested to reduce the contaminants and molecular sidebands generated inside the ion source. First results with ZrC ionizer tubes will be presented. Furthermore, a method to measure the energy distribution of the ion beam as a function of the time of flight will be discussed.