Within the Accelerator and Ion Source Pole of LPSC, the accelerator group is in charge of the design, development, construction and operation of particle accelerators. More precisely, the team is specialized in beam dynamics, beam optics (ions, electrons) and radiofrequency. We are involved in local, national and international projects and collaborations with applications from fundamental physics to nuclear waste treatment. The group activities include R&D, construction and operation of accelerators or accelerator sub-systems and rely on the multiple skills of LPSC technical services.
Since the late 1990’s, the accelerator group is working on electrostatic accelerators producing neutrons with GENEPI-type machines (GEnerator of NEutrons Pulsed and Intense). The first machine GENEPI1 was successfully coupled to the MASURCA reactor (MAquette de SURgénératrice à CAdarache) and operated until it was dismantled from Cadarache. GENEPI2 is under operation at LPSC for the nuclear study platform PEREN (Plateforme d'Etude et de Recherche sur l'Energie Nucléaire) as well as for new applications. The third and last accelerator is operated for the GUINEVERE project (Generator of Uninterrupted Intense NEutrons at the lead VEnus REactor) to drive a nuclear reactor at SCK-CEN (Belgium).
Since 2004, the accelerator group is involved in the national project SPIRAL2 (Système de Production d'Ions Radioactif en Ligne): we are in charge of designing and producing the power couplers feeding the superconducting accelerating cavities of the LINAC.
Currently, our 2 main projects are the electrostatic accelerator for GUINEVERE and the power couplers for the SPIRAL2. We are also responsible for the development and construction of the Low Energy Beam Transport Line (LEBT) of MYRRHA, demonstrator project of a nuclear reactor driven by accelerator at the multi-megaWatt scale.
Our main R&D activities are devoted to multipacting RF phenomenon and high intensity low energy hadron beam transport.
In the past, we have worked on hadrontherapy, a technic using light ions to irradiate tumors for cancer treatment, within the framework of the projects ETOILE in France (Espace de Traitement Oncologique par Ions Légers dans le cadre Européen) and CNAO in Italy (Centro Nazionale di Adroterapia Oncologica).
Regularly, we collaborate with CERN on beam dynamics (LINAC4), RF structures (EUCARD, RFTech, CARE/HIPPI) or production monitoring (inkind contribution from France).
ECR Ion sources developments for accelerators and industrial applications
The ion source team is one of the only groups in the world whose activity is totaly devoted to the development of Electron Cyclotron Resonance Ion Sources, whatever their objectives. This ion source type has been invented by Richard Geller at CEA-Grenoble, in the seventeens. At the origin, they were issued from the modification of a straight magnetic mirror machine dedicated to controlled thermonuclear fusion studies.
Electron Cyclotron Resonance Ion sources
An ECR ion source is a vacuum chamber immersed in a magnetic field and where we inject an HF electromagnetic wave. When the resonance condition (ωHF=eB/me) is satisfied, some energy transfer occurs between the electromagnetic wave and the electrons. A plasma is created, its ionic population characteristics depend mainly on the electrons average energy and on the magnetic confinement. The ions of the plasma are extracted with an electric field established by a set of electrodes placed at the extrimity of the cavity, where the magnetic field lines guide the ions.
The complexity and the cost of an ECR ion source directly depend on the ion beam types to be produced (intensity, energy, nature). These ion sources which are able to produce intense multicharged ion beams initially allowed a renewal of nuclear physics when they were installed on accelerators. Nowadays, they find more and more applications, like accelerators for hadrontherapy to destroy radioresistant malignant tumors with high energy carbon ion beams, or for industrial processes like material treatment and thin layers deposition.
Ion Sources team objectives
The objectives of our team is to design, build and test ion sources prototypes, their characterization diagnostics (beam lines with electrostatic or magnetic devices for transport and analysis, beam diagnostics). To reach these objectives, the ion source team has an excellent support of the LPSC technical departements.
We develop our activities in the frame of local, national, european and international programmes, as well as in collaboration with private companies.
In accelerators projects, the ion source team has an important contribution to the SPIRAL2 construction. This project has been recently modified. Previously, it was organized in two phases, the first one (phase 1) being dedicated to the production of intense stable ion beams, the second one (phase 2) to the production of accelerated exotic ones. Presently the production building and the production of intense exotic beams has been postponed.
For phase 1, our team has the responsability of the design, construction and tests of the high intensity multicharged heavy ion sources. The final objective, when sufficient funding will be available, will be to produce the highest beam intensities in the world (1 mA Ar12+). Moreover, LPSC and "Institut de Physique Nucléaire de Lyon" have performed the construction and the qualification of the low energy beam line of the heavy ions injector, in collaboration with GANIL, CEA-IRFU and Institut de Pysique Hubert Curien. (see SPIRAL2 for more details).
Concerning SPIRAL2 phase II, the ion source team has performed the design and the nuclearization of the charge breeder allowing the multi-ionization of the monocharged ions produced in a target ion source system, in order to allow their subsequent acceleration. This phase II being presently postponed, we have taken the responsability of the design, construction and qualification of the SPES accelerator (INFN-LNL) charge breeder, then in 2015 we will perform the qualification of the SPIRAL1 upgrade charge breeder.
High frequency ECRIS (60 GHz)
Since 2008, we have a research and development activity in high frequency ECR ion sources (60 GHz) in collaboration with the Laboratoire National des Champs Magnétiques Intenses in Grenoble and the Institute of Appllied Physics (Russian Academy of sciences) in Nizhny Novgorod. An ion source prototype based on a polyhelices magnetic structure (high field magnets techniques) has been built by our laboratory in collaboration with the LNCMI, a high power (300 kW), pulsed (50 to 1000 μsec), 60 GHz gyrotron has been designed and built by the GYCOM company and the Institute of Applied Physics, then installed in Grenoble. In March 2014, the first ion beams have been extracted from a 60 GHz ECR ion source having a topologicaly closed ECR resonance zone at 60 GHz (2.14T). The first obtained results are totally new with respect to the state of the art, worldwide.