C. Barué

Ion source developments for RNB production at SPIRAL/GANIL

Abstract The first on-line production system for SPIRAL/GANIL (Radioactive Ion Production System with Acceleration on-Line) phase-I has been commissioned on the SIRa (Radioactive Ion Separator) test bench. Exotic multicharged noble gas ion beams have been obtained during several days. In parallel, a new ECRIS (Electron Cyclotron Resonance Ion Source) for monocharged ions has also been developed. Preliminary off-line results are presented.

High intensity metallic ion beams from an ECR ion source at GANIL

In recent years, progress concerning the production of high intensity of metallic ion beams (58Ni, 48Ca, 76Ge) at GANIL have been performed. The metallic ion from volatile compound method has been successfully used to produce a high intensity nickel beam with the ECR4 ion source: 20 e μA of 58Ni11+ at 24 kV extraction voltage. This beam has been maintained for 8 days and accelerated up to 74.5 MeV/u by our cyclotrons with a mean intensity of 0.13 pμA on target. This high intensity, required for experiment, led to the discovery of the doubly magic 48Ni isotope. The oven method has been first tested with natural metallic calcium on the ECR4 ion source, then used to produce a high power beam (740 W on target, i.e., 0.13 pμA accelerated up to 60 meV/u) of 48Ca still keeping a low consumption (0.09 mg/h). A germanium beam is now under development, using the oven method with germanium oxide. The ionization efficiencies have been measured and compared.

Improvements on metallic ion beams at GANIL with the large-capacity oven

In the last two years the development of the large-capacity oven was continued. First tests on-line with calcium, lead, tin and magnesium beams were achieved. We successfully produced 30μA of Ca9+, 13μA of Pb23+, 8μA of Sn21+, and 50μA of Mg7+. Some deformation of the filament appeared when working at high temperature. Several configurations of the filament and the use of an alternate power supply have been tested to solve this problem. The beam’s intensities and the ionization efficiencies were improved in comparison with the standard microoven performances. The results of magnesium beam, 110μA of Mg5+ obtained with the “MIVOC” method are compared with those using the oven technique.

Status report on ECR ion source operation at GANIL

Two electron cyclotron resonance ion sources, ECR 4 and ECR 4 M, provide high charge state beams to the compact cyclotrons, C01 and C02, which are alternative injectors for the GANIL cyclotrons CSS1 and CSS2. When an injector runs for a long period, the off-line source can be used for beam developments or, together with the off-line injector, deliver a beam to a new beam line, called IRRSUD, for atomic physics experiments. Various ions are requested for beam time for periods of 8 to 11 weeks. Although the majority of the required beams comes from gaseous elements, work on the production of beams of metallic ions is always a main activity. New ovens are being developed to improve the capacity and the performances of the standard micro-oven. The latest results with 238U beam, using sputtering method and 76Ge beam using recycling method, are reported here.

Optimization of ECR singly-charged ion sources for the radioactive ion beam production

Abstract Measurements of the transformation time of atoms into ions were carried out with two 2.45 GHz electron cyclotron resonance ion sources (ECRIS) in the case of the simple ionization of He, Ne, Ar and Kr gases. The effect of the plasma volume, of the dead volumes and of the ionization efficiency are presented. Some rules are deduced for the design of the next ECRIS dedicated to radioactive ion production with noble gases.

Latest results obtained at GANIL with new target-source systems dedicated to radioactive ion production

Two new target-source systems have been realized and used to produce radioactive elements with primary beams of 78Kr (68.5 A MeV) and 36Ar (95 A MeV). The production yields of 73,72Kr, 35,33,32Ar, 30,29P, 31,30S, 34,33,32Cl and of some other condensable elements such as 73,72Br and 73,71Se are presented. The results of the improvements between the two versions of the production system are discussed.

Ion source development at GANIL for radioactive beams and high charge state ions

The GANIL laboratory is in charge of the production of ion beams for nuclear and non-nuclear physics. This article reviews the latest developments that are underway in the fields of radioactive ion beam production, increase of the metallic ion intensities, and production of highly charged ion beams.

Recent results at the SIRa test bench: Diffusion properties of carbon graphite and B4C targets

Abstract The diffusion properties of graphite targets with 1, 4 and 15 microns microstructure has been measured for He and Ar isotopes. An important enhancement of the diffusion efficiency for the smaller microstructure is observed. A releasing efficiency of the order of 100% was obtained for 6 He ( T 1/2 =806 ms) at a temperature of 1600 K. The diffusion and production properties of He isotopes in a target of B 4 C (boron carbide) have also been studied. Yields of 1.4×10 8 pps and 5.0×10 5 pps for 6 He and 8 He has been obtained.

Metallic beam developments for the SPIRAL 2 project

The SPIRAL 2 facility, currently under construction, will provide either stable or radioactive beams at high intensity. In addition to the high intensity of stable beams, high charge states must be produced by the ion source to fulfill the RFQ LINAC injection requirements: Q/A = 1/3 at 60 kV ion source extraction voltage. Excepting deuterons and hydrogen, most of the stable beam requests concern metallic elements. The existing 18 GHz electron cyclotron resonance ion source (ECRIS) Phoenix V2 designed at LPSC Grenoble has been used for the tests and will be the source for the SPIRAL 2 commissioning. The tests performed at LPSC for calcium ((40)Ca(14+) and (40)Ca(16+)), nickel ((58)Ni(19+)), and sulfur ((32)S(11+)) are described and discussed. Due to the very high charge states required, the oven method has been chosen. An intensity of 1 pμA has been reached for those elements. The performance and the beam stability have been studied using different buffer gases, and some ionization efficiency preliminary results are given.

Roadmap for the design of a superconducting electron cyclotron resonance ion source for Spiral2

A review of today achieved A∕Q = 3 heavy ions beams is proposed. The daily operation A∕Q = 3 ion beam intensities expected at Spiral2 are at the limit or above best record 3rd generation electron cyclotron resonance ion source (ECRIS) intensities. The necessity to build a new fully superconducting to fulfill these requirements is outlined. A discussion on the volume of the future source is proposed and the minimum value of 12 liters is derived. An analysis of the x-ray absorption superconducting ECRIS is presented based on VENUS experimental data and geometry. This study underlines the necessity to include a complete x-ray study at the time of source conception. The specifications foreseen for the new ECRIS are presented, followed with the roadmap for the design.