N. Lecesne

An overview on TRIUMF’s developments on ion source for radioactive beams (invited)a)

The ISAC facility at TRIUMF utilizes up to 100 microA from the 500 MeV H(-) cyclotron to produce the radioactive ion beam (RIB) using the isotopic separation on line method. The ISAC-I facility comprised the RIB production target stations, the mass separator, and the beam delivery to low energy area and to a room temperature linear accelerator composed of a four-rod radio frequency quadrupole and an interdigital H-type structure drift tube LINAC. ISAC-I linear accelerator can provide beam from A=3 to 30 amu with an energy range from 0.15 to 1.5 A MeV. Since the beginning of operations target development program has been to increase proton beam currents on targets. Now we routinely operate our target at 50-85 microA and recently we have operated our target at 100 microA. Other developments are in place to add other ion sources, laser, force electron beam induced are discharge and electron cyclotron resonance ion source to the actual surface ion source. The last two five year plans were mainly devoted to the construction of a heavy ion superconducting LINAC (ISAC-II) that will upgrade the mass and the energy range from 30 to 150 and from 1.5 to 6.5 A MeV, respectively. The intermediate stage E< or =4.2 A MeV is already completed and commissioned; three experiments using (11)Li, (9)Li, and (29)Na have been completed this summer.

The radioactive ion beam production systems for the SPIRAL2 project

The SPIRAL2 project, currently under construction at GANIL, will include an isotope separator on line based facility for the production and acceleration of radioactive ion beams. A superconducting linear accelerator will accelerate 5 mA deuterons up to 40 MeV and 1 mA heavy ions up to 14.5 MeV/u. These primary beams will be used to bombard both thick and thin targets. We are investigating three different techniques to produce the radioactive ion beams: (1) the neutron induced fission of uranium carbide, (2) the direct interaction of deuterons in a uranium carbide target, and (3) the interaction of a heavy ion beam with a target. All these production systems will be coupled to an ion source. Four kinds of ion sources are foreseen for the ionization of the radioactive atoms: an electron cyclotron resonance ion source, a surface ionization ion source, a forced electron beam induced arc discharge ion source, and a laser ion source depending on the characteristics of the desired radioactive ion beam in terms of intensity, efficiency, purity, etc. A presentation of the SPIRAL2 project and of the different production systems is given.

Minimono: An ultracompact permanent magnet ion source for singly charged ions

Minimono is a 2.45 GHz electron cyclotron resonance ion source for singly charged ions which uses only permanent magnets. Measurements of ionization efficiencies, maximum currents extracted, and emittances for H+, 3,4He+, N+, Ne+, Ar+, Kr+, S+, and Si+ were carried out. In the case of buckminster fullerenes, C60+, C602+, and C603+ ions were extracted. The results obtained, the general mechanical simplicity of this ion source, and its low cost make this source attractive for the production of stable and radioactive ions.

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.

Visible light spectrometry measurements for studying an ECRIS plasma and especially applied to the MONO1001 ion source

The cylindrical geometry of the magnetic confinement of the MONO1001 electron cyclotron resonance (ECR) ion source made in GANIL [P. Jardin et al., Rev. Sci. Instrum. 73, 789 (2002)] allows us to measure radial characteristics of the working ECR plasma with helium gas. The physical and the geometrical characteristics of the resonance surface inside the working ECR source have been quantified with the help of a visible light spectrometer. Hence, we have deduced a shape of the electron cyclotron resonance ion sources resonance surface which corresponds closely to our magnetic calculations.

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.

Radioactive ion beam production at GANIL: Status and prospectives

Production of radioactive ions has started at GANIL on the SPIRAL facility since 2001 and numerous multicharged radioactive ion beams have been delivered for high energy nuclear experiments. This article makes an overview of the different beams that have been produced. In the mean time, an important R and D research program is continued in oder to produce new species of radioactive elements. A new concept of multicharged radioactive production that couples a monocharged ion source, based on the monolithe concept, to an ecr ion source like nanogan3 is under developments and is described The development of monocharged ion sources with high efficiencies is also motivated by a new big project that is under studies at GANIL : the SPIRAL 2 Project. The goal of this project consists in extending the disponible radioactive ion beams to very heavy elements created with a new method of production : while the spiral 1 facility uses the projectile fragmentation for radioactive nuclei production, the spiral 2 project is based on the fission of a Uranium carbide target induced by a neutron flow created by a high intensity deuton beam. The principle and an overview of the project is presented.Production of radioactive ions has started at GANIL on the SPIRAL facility since 2001 and numerous multicharged radioactive ion beams have been delivered for high energy nuclear experiments. This article makes an overview of the different beams that have been produced. In the mean time, an important R and D research program is continued in oder to produce new species of radioactive elements. A new concept of multicharged radioactive production that couples a monocharged ion source, based on the monolithe concept, to an ecr ion source like nanogan3 is under developments and is described The development of monocharged ion sources with high efficiencies is also motivated by a new big project that is under studies at GANIL : the SPIRAL 2 Project. The goal of this project consists in extending the disponible radioactive ion beams to very heavy elements created with a new method of production : while the spiral 1 facility uses the projectile fragmentation for radioactive nuclei production, the spiral 2 project ...

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.