The Advancement of Spiral 2 Project

After a detailed design study phase (2003-2004), the SPIRAL2 project at GANIL (Caen, France) was officially approved in May 2005, and is now in its phase of construction, with a project group in which many French laboratories (CEA,CNRS) and international partners are participants. The SPIRAL2 facility is composed of a multi-beam driver accelerator (5mA/40Mev deuterons, 5mA/33Mev protons, 1mA/14.5 Mev/u heavy ions), a dedicated building for the production of radioactive ion beams (RIBs), the existing cyclotron CIME for the post acceleration of the RIBs, and new experimental areas. It will deliver high intensity beams for radioactive ion production by the ISOL method (the main process being the fission of a uranium carbide target), and stable heavy ions for nuclear and interdisciplinary physics. A high intensity neutron flux will also be produced for irradiation and time-of-flight experiments. In this paper we describe the various parts of this facility, the results obtained with prototypes of several major components, the status of the construction itself, and the research and development which remains to be done in some domains, including safety aspects. INTRODUCTION AND OPPORTUNITIES FOR PHYSICS EXPERIMENTS A strong demand exists for availability of radioactive isotope beams. NuPECC and ESFRI have established roadmaps and given recommendations for the future of nuclear physics and facilities in Europe. SPIRAL2 is one of the selected projects. This new facility will extend the possibilities offered at GANIL to heavier radioactive beams, with much higher intensities [1]: it will provide intense beams of neutronrich exotic nuclei (10–10pps), created by the ISOL production method, in the mass range from A=60 to A=140. The extracted exotic beam will be used either in a new low energy experimental area called DESIR, or accelerated by the existing SPIRAL 1 cyclotron (CIME). The intense primary stable beams (deuterons, protons, light and heavy ions) will also be used at various energies for neutron-based research, irradiation and activation studies and multi-disciplinary research, all these experiments taking place in a new area (AEL). Originally proposed in June 2002 [2], and after detailed design studies [3][4][5], SPIRAL2 was accepted in May 2005, and is now in its construction phase, with the objective of obtaining the first beams for physics by the end of 2011. Many French laboratories participate in the construction of the SPIRAL2 facility, and there are numerous European and international collaborations, either for the accelerator itself or for which the physics areas. In what follows, we give a description of the main parts of the machine, and the status of its construction. SPIRAL2 DRIVER ACCELERATOR AND AEL EXPERIMENTAL AREA Beams to be accelerated In order to fulfil the physics requirements, the SPIRAL2 driver accelerator must be able to accelerate high-intensity beams of protons, deuterons, ions with A/q<3, and optionally ions with A/q<6. As indicated in table 1, a maximum beam power of 200kW is required for deuterons in CW mode. In order to transport and accelerate these intense beams with a minimum of losses, many beam dynamics calculations have been performed all along the machine, by using realistic source particle distributions, real 3D magnetic fields, compensation space charge effects in various situations, and also with systematic errors studies [6][7]. The whole driver accelerator will be controlled using the EPICS software [8] coupled with the TRACEWIN/PARTRAN code in order to implement the notion of a “virtual machine”. Table 1: Beam Specifications beam P+ D+ ions ions