The GANIL facility

• Prof. Sydney Gales, Directeur adjoint scientifique de l’IN2P3 (Institut de Physique Nucléaire et Physique de Particules) et directeur du GANIL

Prof. Sydney Gales accepted the invitation on 8 July 2009 (self-imposed deadline: 8 February 2010).

GANIL-SPIRAL-SPIRAL2: A Heavy-ion accelerator facility: for the European and International community

GANIL-SPIRAL

GANIL, Grand Accélérateur National d’Ions Lourds (National Large Heavy Ion Accelerator), in Caen, Basse-Normandie, France provides heavy ion beams for nuclear and atomic physics, astrophysics, material science and radiobiology. GANIL-SPIRAL is the largest accelerator complex in France and one of the two largest facilities for heavy ions in EUROPE along with GSI in Darmstadt (Germany). The installation shown in Figure 1 was jointly created and constructed by two research organizations, CEA/DSM and CNRS/IN2P3. It is jointly operated as an Economic Interest Group (GIE). In August 1975, the decision was taken to build this laboratory in Caen. The region of Basse-Normandie strongly supported the project by a substantial financial contribution.

Figure 1: GANIL complex situated in the north of Caen

The first beam was delivered in November 1982, and the first experiment took place in January 1983. In the following years, the laboratory continuously developed and acquired a worldwide reputation in the field of nuclear physics. In 1995 it was given the status of a European Large Scale Facility for research. A major upgrade was achieved in 2001 with SPIRAL, with the addition of the ISOL (Isotope Separation on Line) technique for the production of secondary beams of light exotic ions and subsequently accelerated by a new cyclotron. This complemented the already available production of secondary beams by using the in flight method. GANIL is continuously evolving developing and a major step being the signature, in 2006, for the construction of SPIRAL2. The construction of the buildings of SPIRAL2 is expected to begin in 2010. This new facility places the region of Basse-Normandie in a strong position to host the next generation of exotic beam factory, a large European project proposed by the European nuclear physics community called EURISOL.

GANIL IN NUMBERS

• 9.3 million € operating budget
• 77 institutes conducting a programme of nuclear physics, of which 65 are foreign laboratories and universities
• 100 trainees and doctorate students each year
• 255 CEA, CNRS permanent staff positions (2010)
• 725 researchers from 30 different countries perform experiments regularly at GANIL.
• 3020 publications based on work at GANIL

GANIL IN DATES

• 1975: Creation of GANIL
• 1982: Creation of CIRIL
• 1983: First experiment
• 1989: First upgrade: Increase in beam energy
• 1990: Construction of SME, a parasitic medium-energy beam line
• 1994: Second upgrade: Increase in primary beam intensities
• 1994: Construction of SISSI for production of exotic nuclei
• 1995: Status of a European Large Scale Facility
• 2001: First beams from the SPIRAL facility
• 2003: Creation of LARIA, a laboratory of radiobiology
• 2004: Creation of IRRSUD, a new low-energy beam facility
• 2005: Decision to build SPIRAL2
• 2005: Inauguration of ARIBE, a very low-energy beam facility
• 2006: Signature of the SPIRAL2 convention
• 2008: Anniversary of 25 years of research at GANIL

NATIONAL AND INTERNATIONAL IMPACT

• European Large Scale Facility” status in 1995
• One of the two main European facilities for the production of rare isotope beams
• One of the five leading laboratories worldwide for research with energetic heavy ion beams
• 25 international conferences
• 60 national and international workshops
• 27 scientific awards including 4 “CNRS Crystal” prizes
• Partnership with 65 foreign laboratories and universities worldwide

GANIL Organization and Committees

• Executive Board of directors 10 members (5 CNRS-5 CEA)
• International Scientific Council (15 Members, 3 French)
• International Program Advisory Committee
• International review committee (every 4-5 years)
• SPIRAL2 Steering Committee
• International Scientific Advisory Council (SAC) and Technical Advisory Council (TAC) for SPIRAL2

The Science Pillars of GANIL

In nuclear physics, GANIL has enabled numerous discoveries related to new structures in atomic nuclei, the thermal properties of nuclei and mechanisms of interaction and in the creation of new nuclear species (referred to as ‘exotic’ because they do not occur in nature).
MATTER IN THE CORES OF SUPERNOVAE: More than 99.9% of the observable mass is concentrated in the heart of the atom – the nucleus, which is also the fuel in stars – their dimensions being less than one hundredth of a billionth of a millimetre! The nuclear material acts like a liquid, boiling at some 100 000 000 000 degrees, the temperature found at the core of the biggest stars when they explode into a supernova. Many experiments are dedicated to the study of the thermo-mechanical properties of nuclear matter.
THE FORMATION OF ELEMENTS IN THE UNIVERSE AND LIFE OF THE STARS: The stars are cauldrons where new atoms are cooked. Nuclear reactions are at the basis of creation of atoms in the universe and help us in understanding the energy generated by the stars. At GANIL, physicists study these reactions and the structure of atomic nuclei to obtain a better understanding of stellar evolution.
NUCLEI IN THE UNIVERSE: For 13.5 billion years, following the Big Bang, the stars have been transmuting light atomic nuclei starting from hydrogen into heavier elements. The Earth is formed from the cooled ashes of these cosmic cauldrons. Only 291 different isotopes of 92 elements have survived of the thousands (7000 according to some models) which could exist in the Universe. GANIL facilitated the production and study those isotopes which do not exist on Earth: the exotic nuclei. They are the key to our understanding of the origin and the structure of matter. More than 100 nuclei have now been discovered at GANIL since the first beam became available in 1983; many hundreds have been characterized for the first time and more remain to be discovered.
HALOS OF NEUTRONS: In 1985 the halo of neutrons was discovered. Indeed, the experiment that started the field of halo physics was published in 1985, so in a sense the halo was discovered in 1985 whereas the nuclei 6He, 11Li and 11Be having halos were known much earlier. With the unique beams of helium 6 and helium 8, formed by a Helium 4 core, surrounded by a “cloud” of 2 and 4 neutrons, respectively, GANIL has facilitated a systematic exploration of this enigmatic structure: observation of the orbits of the neutrons, synthesis of super-heavy hydrogen having 1 proton and 6 neutrons, search for neutronic matter, nuclei without any protons, measurement of the size of nuclei trapped by lasers, studies of their reactions and their excited states.
MODIFICATION OF SHELL STRUCTURE: In stable nuclei, protons and neutrons arrange themselves into a system of well-defined and ordered shells. Studies of exotic nuclei have shaken this paradigm. To understand this, physicists are trying to locate these shells, by adding or removing nucleons to the exotic nuclei produced at GANIL. The modes of interaction between the protons and the neutrons can be analysed by studying the ordering of shells.
NUCLEI OF MANY SHAPES: By producing exotic nuclei and studying their reactions with other nuclei, physicists can deduce their shape. They have also discovered that certain exotic isotopes of Krypton possess two independent shapes, looking simultaneously both elongated and flattened.
TRAPS FOR STUDY OF FUNDAMENTAL INTERACTIONS: Exotic nuclei spontaneously decay into more stable nuclei by transforming a neutron into a proton or vice-versa. This is the well known “beta” radioactivity. By trapping exotic nuclei using magnetic fields or lasers, physicists discover its secrets and learn about the fundamental interactions mediating its beta decay.
INTERDISCIPLINARY RESEARCH: By strongly disturbing the electrons responsible for the cohesion of matter, ion beams produced at GANIL can also be used to study the stability and relaxation pathways of this excited matter together with the resulting structural and physico-chemical modifications. This research domain concerns atomic and molecular physics, irradiated materials, physics of solids, chemistry under radiation and radiobiology as well as applications of the effects induced by ions. To promote this interdisciplinary research at GANIL the Centre for Interdisciplinary Research of Ions and Lasers (CIRIL) managed by CIMAP, was created

The GANIL-SPIRAL facility today

GANIL is today one of the five largest laboratories in the world for research using beams of ions to study the physics of the atom and its nucleus, to investigate problems of importance for radiotherapy, and to address a variety of questions from condensed matter to astrophysics. The layout of GANIL facility (Grand Accélérateur National d’Ions Lourds), Caen, France is shown in Figure 2. The production of stable and radioactive ion beams for nuclear physics studies represent the principal activity of GANIL. Two complementary methods are used for exotic beam production: the Isotope Separation On-Line (ISOL, the SPIRAL1 facility) and the In-Flight Separation technique (IFS). SPIRAL1, the ISOL facility, is running since 2001, producing and post-accelerating radioactive ion beams. Below the various operating modes of the accelerators as well as a review of its operation from 2001 to 2008 are presented. Future plans for the facility connected with the use of high intensity ion beams and improvements in the production of exotic beams are also briefly discussed.

Figure 2: Layout of the GANIL facility

Running modes
Using its 5 cyclotrons GANIL-SPIRAL is a truly multi-beam facility. Up to six experiments can be simultaneously run in different experimental areas using stable beams :

• Using beams from C01 or C02, an irradiation beam line IRRSUD at energies of 1 MeV/A.
• Exploiting one charge state of the ion distribution downstream CSS1 after the ion stripping, a beam line provides beams in the energy range 4-13 MeV/A beams, for atomic physics, biology, solid state physics.
• A high-energy experiment using beams after CCS2.
• An auxiliary experiments sharing the above CSS2 beam
• Additionally, the cyclotron CIME (SPIRAL post-accelerator) delivers stable beams for nuclear physics and detector tests.
• An independent facility (ARIBE) is providing heavy-ion beams at energies of a few keV.
  During radioactive beam production, up to four experiments can be run simultaneously.

Intense primary beams

In 1990 an upgrade of the accelerators was made. As a result of which a wide spectrum of high intensity ion beams ranging from ¹²C to ²³⁸U accelerated up to 95 MeV/A was available. The acceleration scheme uses three cyclotrons in tandem, one compact (C01 or C02, K=30) followed by two separated sector cyclotrons (CSS1 and CSS2, K=380). These accelerators and beam lines have been adapted to transport intense ion beams. More than 10 beams of elements from C to Kr are available at a power exceeding 1 kW and over 50 stable-ion beams are available from the GANIL ion-sources. The monitoring of beam losses by suitable detectors, beam transformers and control system allow the transport of these intense stable beams with power exceeding 3 kW in routine operation. An average of 10000 hours of beam time is delivered every year by the GANIL facility.

Secondary exotic beams

Exotic beams are produced by two complementary methods.

The so-called "In flight method" using the LISE separator and/or SISSI (Superconducting Intense Source for Secondary Ions) consists of fragmenting the intense primary beams interacting with a rotating target. The exotic cocktail beam, with an initial beam like velocity, is purified with a magnetic separator and sent to various experimental areas. Since October 1994, SISSI device was used to produces secondary radioactive beams in a very efficient way. The beam is focused to a 0.4mm diameter spot on a thick rotating target using a superconducting solenoid having a maximum field of 11Tesla. A second identical solenoid after the target improves the angular acceptance downstream and thus increases the collection of the secondary exotic ions. The cooling system is provided by a circuit of liquid helium at 4.6°K. The target is a disk rotating at 2000rpm disk, so that the radiated heat is spread over a much larger area than the beam spot. In July 2007 the operation of the SISSI device was stopped due to a major failure of the superconducting coils .The fragmentation production of “exotic” beams is now carried out at the LISE facility operating with the new high-power CLIM rotating target.

The ISOL method with SPIRAL, a new dedicated facility built at GANIL between 1995 and 2000. For the production and acceleration of radioactive ions with the ISOL method, the stable heavy ion beams of GANIL are sent into a target and source assembly. The radioactive atoms produced through nuclear reactions are released from the target, kept at high temperature, into an ECR source. After ionization and extraction from the source (extraction voltage < 34kV), the multi-charged radioactive ions can be used at the low-energy facility LIRAT or accelerated up to a maximum energy of 25 MeV/A by the compact cyclotron CIME (K=265). The first SPIRAL beam delivered for the physics experiments was ¹⁸Ne in October 2001. Since, then more than 30 radioactive beams were produced in 8500 hours of SPIRAL operation over 23600 hours of the total beam time delivered to nuclear physics experiments. A schematic description of SPIRAL facility is shown below in Figure 3.

Figure 3: The SPIRAL-ISOL facility at GANIL

SPIRAL IN NUMBERS

• 1994: the “White Book” defining the scientific objectives of the project
• 2001: first exotic beam produced and accelerated at SPIRAL
• 200 000 000: exotic helium-6 nuclei extracted per second
• 31: the mass of the most neutron-deficient exotic argon ion produced, with 5 neutrons less than the lightest stable argon isotope
• 46: the mass of the most neutron-rich exotic isotope of argon produced, with 6 neutrons more than the heaviest stable argon isotope
• 6 and 8: masses of helium isotopes, among the most used and intense beams of “exotic species” at GANIL and worldwide
• 32: experiments done in 5 years
• 30: isotopes of 7 gaseous elements produced and accelerated
• 30: publications on technical developments
• 60: scientific publications

Figure 4: Beam time shared over the years between GANIL beam (out of CSS) and SPIRAL1 beams (out of CIME)

GANIL: the tools for fundamental research in nuclear physics

In addition to high power and the variety of stable and Radioactive Ion Beams (RIB) available for research at GANIL, the facility offers a set of detectors and spectrometers (the “eyes of the physicist”) which are unique in the world. As shown in Figure 2 they are installed in dedicated experimental vaults along the central fishbone beam line. Brief descriptions of these major tools are given below.
VAMOS-EXOGAM: The coupling of a magnetic spectrometer having a large acceptance (VAMOS) with an array of Germanium gamma detectors of high efficiency (EXOGAM) opens avenues to study nuclei far from stability. The spectrometer permits the identification and selection of products generated in reactions with beams of exotic ions. The detection of the corresponding gamma-rays then allows identification of the excited levels of these reaction products.
SPEG: A magnetic spectrometer which furnishes precise information on the reaction products: angle of emission, energy, charge and mass of the reaction products.
INDRA: A multi detector charged particle detector array designed for the study of hot nuclei pushed to the extreme limits of cohesion.
LISE: A beam line initially dedicated to the study of atoms stripped of their electrons. Over time it has been transformed to permit the production and analysis of exotic nuclei at the limits of our knowledge.
LISE is a fragment-separator and have been the pioneering tool for the physics of “exotic nuclei”. Many laboratories around the world inspired by this instrument have built in recent year’s new versions of this device (MSU-NSCL, RIKEN, FLNR-JINR, LANZHOU, and GSI).
SIRA: A test-bench for the target-and-ion-source assemblies for SPIRAL, which permits the optimizing of the production of beams of exotic nuclei.
MUST2: A large array of Silicon strip detectors for the study of nuclear reactions.
LIRAT: A dedicated beam line to transport very low energies (30keV/n) RIB to study ground state and decay properties.

GANIL 2015: Future developments

The SPIRAL2 project will increase considerably the capabilities of the GANIL facility. The use of both the new SPIRAL2 beams and those from the existing GANIL are envisaged to be used in the existing experimental halls. A committee referred to as GANIL2015 was created to identify necessary modifications of the present facility in the near future. One of the main recommendations of this committee was to extend the range of radioactive ion beams available from the SPIRAL1 facility. In this context the highest priority, was assigned to the study related to the modification necessary for the incorporation of a charge breeder in the existing SPIRAL1 acceleration scheme. Additionally, detailed studies to facilitate the use the high intensity beams from SPIRAL2 in the experimental halls are to be carried out. The evolutions related to the accelerators to take into account the committee recommendations are now briefly described. Most of the ions produced in SPIRAL are gases (He, O, Ne, Xe etc...). The presently used 1+/N+ ion source has a very low efficiency for extracting other species. Therefore, a modification of the coupled target-source needs to be studied. To avoid delays arising from major modifications of the existing irradiation cave that could arise due to constraints from safety regulation, it has been decided to study options for new sources that fit in the existing area.

Charge breeding for SPIRAL1
In order to create new ion species and subsequently accelerate them through the CIME cyclotron, the implement a 1+ source in the irradiation cave was found to be a good solution. The atoms produced in the fragmentation of the primary beam in the carbon target of SPIRAL are ionized in an ion source. The higher charge state necessary to accelerate these ions through the cyclotron is done via a charge breeder outside the cave. Such a solution due to its smaller dimension compared to an ECR source is compatible with the existing mechanical constraints.

Intensity increase (primary and secondary beams)
The increase of the ion beam intensities is possible for both stable and the exotics beams as well. The limits of beam intensity arising from safety limitations: 2x10¹³ ions per second or 6 kW out of CSS2 and 5x10¹¹ ions per second out of CIME. Presently a few beams mostly light ion species are already at these or close to reach these limits. Significant improvements are still possible for heavier ions. A new GANIL Test Source (GTS) is expected to be commissioned by the middle of 2010. With respect to the intensities of exotic beams the production is limited by the power handling capacity of the carbon target. Two types of target exist: one for the ^6,8He production that can handle 3 kW beams and another where the power is limited to 1.5 kW for other ion species. An increase of the power to 6 kW beam shows a potential improvement of the production by a factor between 2 to 4. The replacement of the ECR source will also open the possibility of accelerating metallic beams. The sustained maintenance of the existing accelerators has kept their performance optimal and one expects that it would be possible to further increase their performances.

A NEW ERA FOR THE COMING DECADES: SPIRAL2

Since the production of the first beams, GANIL has been a pioneer in the study of exotic nuclei. The LISE beam line became one of the first installations to synthesise new nuclei, inspiring many laboratories all around the world. This emerging field of research, became, a rich source of information on the physics of nuclei far from stability. TERRA INCOGNITA Today, with exotic beams from LISE2, LISE 2000 and SPIRAL, GANIL is one of five leading laboratories in the world. Tomorrow, with SPIRAL2, GANIL will take a giant step forwards in the international arena.

SPIRAL2 - AN EXOTIC NUCLEUS FACTORY

The SPIRAL 2 facility (Figure 5) is based on a high power, superconducting driver LINAC, which will deliver a high intensity, 40 MeV deuteron beam as well as a variety of heavy-ion beams having a mass over charge ratio of 3 and energy up to 14.5 MeV/n. Using a carbon converter, the 5 mA deuteron beam and a uranium carbide target, fast-neutron induced fission is expected to reach rates up to 10¹⁴ fissions/s. The RIB (Radioactive Ion Beams) intensities, in the mass range from A=60 to A=140, will surpass by one to two orders of magnitude those from existing facilities in the world. A direct irradiation of the UCx target with beams of deuterons, ^3,4He, ^6,7Li, or ¹²C can be also be used if the available higher excitation energy leads to a higher production rate for nuclei of interest.

Figure 5: Schematic layout of the SPIRAL 2 facility at GANIL

The stable heavy-ions available from the linac accelerator will reach intensities up to 1 mA. These heavy-ion beams will be used to induce fusion and deep inelastic reactions leading to the production of neutron and proton rich isotopes. Similarly, the heavy- and light-ion beams from the LINAC on different production targets can be used to produce high-intensity light RIB using the ISOL technique. The extracted RIB will be subsequently accelerated to energies of up to 20 MeV/n, (Typically 6-7 MeV/n for fission fragments), by the existing CIME cyclotron. Thus using different production mechanisms and techniques SPIRAL 2 would allow performing experiments on a wide range of neutron- and proton-rich nuclei far from the line of stability, as shown by the chart of nuclides of Figure 6.

Figure 6: Region of the nuclear mass chart accessible with SPIRAL2 beams. The white squares are the 291 nuclei which one finds naturally on Earth. The light blue areas denote the 2000 nuclei synthesised in the laboratory today. The dark blue areas correspond to the ensemble of nuclei predicted by theory to exist in the Universe: in total, between 5000 and 7000 nuclei. The areas coloured in pink and red indicate the nuclei, which can potentially be produced and accelerated as beams from SPIRAL2. Thanks to very high intensities, SPIRAL2 will make possible a whole range of experiments, which were not feasible with the first generation of RIB facilities.

SCIENTIFC CHALLENGES FOR SPIRAL2

• The quest for super heavy nuclei: Scientists can predict the existence of very heavy nuclei composed of 114 to 126 protons and 184 neutrons. These chemical elements, 1.5 times heavier than lead, are known as superheavy nuclei. They are now actively being sought after, and the high intensity of the SPIRAL2 beams, as well as its new detectors, will be major assets in this quest.
  
• The revolution of magic numbers: Nuclei are found to be extremely stable when they have 2, 8, 20, 28, 50, 82 or 126 protons or neutrons. These are the nuclear "magic numbers". The structure of exotic nuclei seems to take no heed of these known magic numbers. Depending on how far the exotic nuclei are from the valley of stability, known magic number disappear while others appear. With SPIRAL2, the evolution of magic numbers will be monitored up to the boundaries of the existence of nuclei, in an attempt to understand this still poorly understood phenomenon.
  
• The nuclear cohesive forces: The properties of exotic nuclei, their cohesion, size, excited levels, shape, etc., are determined by a subtle balance between the forces they experience. Through intensive modelling, the results from SPIRAL2 will help determine these forces, especially in neutron-rich nuclei.
  
• The origin of heavy elements in the Universe: A fundamental challenge in Nuclear Astrophysics is the understanding of the formation of trans-ferric elements. The site for the production of many of the elements heavier than iron, including gold, platinum and uranium is still unknown. Nuclear physics is necessary to provide inputs required to understand the underlying reaction processes. The experimental determination of reactions rates on unstable nuclei that play a critical role in Novae and X-ray bursts –in particular the α, p and rp processes have just begun. Even CNO reaction that powers the stars is expected to hold surprises. The future SPIRAL2 facility will contribute prominently to several areas of active research in nuclear astrophysics, such as explosive hydrogen burning, s-process and r-process nuclear synthesis, which are linked to astrophysical observations (novae, X-ray bursts, type2 supernovae, etc). In the case of the r-process, transfer reactions like the (d,p) reaction can be used to simulate the (n,γ) capture on medium-mass nuclei at SPIRAL2 near the possible paths for the r-process. The neutron rich isotopes of Sn and Cd nuclei are excellent cases to be investigated.
  
• The nuclear matter of neutron stars: The protons and neutrons in a nucleus form a liquid of "extraordinary" density. A neutron-rich liquid constitutes the heart of supernovae and neutron stars. SPIRAL2 will recreate this kind of matter on Earth, in reactions with highly neutron-rich projectiles.
  
• Fundamental interactions: Exotic nuclei transmute into more stable species by, in particular, emission of beta radioactivity. They can therefore be used to study the fundamental properties of the weak nuclear force which causes this phenomenon.
  

SPIRAL2 has also remarkable potential using beams of neutron both for fundamental physics and various applications. In particular, this facility will provide neutrons in the energy range from a few MeV to about 35 MeV, of higher energy compared to other neutron facilities in operation or under construction worldwide. This new experimental platform offering outstanding opportunities to interdisciplinary research will bring together the communities of atomic physics, solid-state physics, and radiobiology on the study of irradiated matter.
Last but not least one of the important features of the future GANIL/SPIRAL/SPIRAL2 facility will be the possibility to deliver up to five stable or radioactive beams simultaneously in the energy range from keV to several tens of MeV/n.

ORIGIN AND LIFE OF A BEAM OF EXOTIC NUCLEI

The nuclei of hydrogen-2, also called deuterons, consist of one proton and one neutron. These were created several minutes after the “Big Bang”. Combining with nuclei of hydrogen-1 and oxygen, they form “heavy water” because the deuterons are twice as heavy as their hydrogen-1 siblings, which consist of only one proton. Within the ion source of SPIRAL2, the hydrogen-2 atoms are stripped of their electrons to become ions. These deuterons are then accelerated by the intense oscillating electric fields of LINAC. The beam thus formed bombards first a target of carbon, the converter. During the collisions between the deuterons and the carbon nuclei, a strong flux of fast neutrons is generated. These then interact with a second target of uranium, causing the uranium nuclei to fission. The exotic atoms thus created as fission fragments are stripped of some of their electrons in an ion source connected to the target, after which they will be mass-selected and accelerated by the CIME cyclotron. The even more exotic nuclei so produced will be observed during various nuclear reactions, with extremely sophisticated detectors.

INFRASTRUCTURE

The construction phase of SPIRAL2 started in 2006. SPIRAL2 will be built in GANIL campus and will almost double the current area of the facility, increasing from around 11 000 m2 to 20 000 m2. The civil construction is divided into two phases. Phase 1 includes the construction of the LINAC building and associated experimental areas (AEL). This is planned to be completed by the beginning of 2012 along with the commissioning of first beams from LINAC. The second phase (RIB production building and dedicated low energy ISOL facility, DESIR) will begin in 2011 aiming to be ready by 2014. The components of the LINAC are under construction, including serial production of super-conducting RF cavities, ion sources, injection and other beam-line components. The accelerator, beam lines, AEL experiment hall and the exotic ion production process will be installed in an underground tunnel (-8.5 m). To respect environmental regulations SPIRAL2 has followed the criteria laid down by the HQE (High Environmental Quality) and the procedure called "Control the impacts on the external environment" regarding the design and construction of the new installation. In addition to an entrance hall and areas for various departments, SPIRAL2 will include a group of 5 buildings:

• - the accelerator building housing the ion sources (deuterons, protons and heavy ions), the linear accelerator (LINAC) and the beam distribution lines,
• - the building of the Experimental Areas associated with the LINAC (AEL),
• - the exotic ion production building,
• - the building intended for low energy experiments (DESIR),
• - the annex building where the auxiliary units will be installed

THE TECHNOLOGIES - Accelerator and Ion Sources

The SPIRAL2 LINAC
An ion source strips the electrons from the atoms to convert them into positively charged ions. The charged ions can then be accelerated by electric fields and transported by magnetic fields. SPIRAL2 ion sources use innovative concepts to produce beams of the highest intensity. The accelerator consists of two ion sources coupled to a series of accelerating cavities optimised as per the energy to be given to the particles. The first cavity, RFQ, is made from ultra-pure copper. The next 26 cavities made from superconducting niobium operate at -269 °C, cooled with liquid helium. They are distributed in 19 cryomodules. Together, they can be used to reach energies of 40 000 000 electron-volts. The first 12 cryomodules take over from the RFQ to accelerate contain cavities optimised for particles travelling at 7 % of the speed of light. The next 7 cryomodules each contain two cavities optimised for particles travelling at 12% of the speed of light. The electromagnets distributed along the accelerator focus and direct the beam of particles through tubes kept under vacuum.

NIOBIUM FOR OPTIMUM CURRENT
The cavities which will be used for SPIRAL2 are made from Niobium, a soft ductile and shiny white metal. Niobium is one of the known superconducting materials. At very low temperature, current can flow through the metal with no loss of energy. Oscillating electric fields of very high intensity can therefore be created, up to 12 000 000 volts per metre.

New experimental areas and detectors for SPIRAL2

A process leading to the definitions of the new experimental areas, detectors and associated collaborations was initiated in March 2006 by the Scientific Advisory Committee (SAC) of SPIRAL2 (4). A call for Letters of Intents (LoI) was launched and were evaluated at the end of 2006. A first targeted call for full technical proposals related to two news experimental areas NFS and S3 and using directly intense heavy ions and p,d beams from the LINAC was launched in 2008. Within the SPIRAL2 project these two new experimental areas will host, respectively, the Neutron for Science facility (NfS) (Neutron converter and time of flight hall) and the Super Separator Spectrometer (S3) devoted to in flight production of exotic nuclei and to Super Heavy Elements (SHE) using intense heavy ions Linac beams (see Fig. 7). Another experimental area devoted to the low energy RIB has been proposed by the DESIR (Decay, Excitation and Storage of Radioactive Ions) collaboration. At this low-energy beam facility DESIR, there is an opportunity of building and utilizing a variety of apparatus to explore essentially all ground state properties of exotic nuclei. For example a ß-NMR setup will be suitable to study precisely the moments of key nuclei and, in combination with collinear hyperfine spectroscopy, assign unambiguous spin assignments for various nuclei. With a collinear spectroscopy setup, it will be possible to study series of isotopes in the intermediate and heavy mass regions. For the heavy elements, a double laser + RF spectroscopy in a Paul trap will be used to study the hyperfine anomaly and higher-order moments up to very high precision. In addition to these new experimental areas, the LoI’s process has induced the formation of collaborations around several new detectors (Figure.7).

Figure 7: New experimental areas and detectors to be used with GANIL/SPIRAL1/SPIRAL2 facility

EXOGAM2 (Exotic & GAMma) is a new digital electronic system for the existing EXOGAM gamma ray detection assembly installed at GANIL. This system is necessary in order to exploit the high count rates from the detectors to characterize gamma radiation produced by the reactions induced by the SPIRAL2 beams. FAZIA (Four-pi A and Z Identification Array) is a new generation multi-detector, designed to detect electrically charged particles, in order to study the dynamics and thermodynamics of nuclear matter. It allows high-resolution identification of the particles produced during collisions of nuclei with a target. Intended for the physics of direct nuclear reactions, GASPARD (Gamma Spectroscopy and PARticule Detection) is a highly efficient detector, especially for the simultaneous detection of particles and gamma radiation. PARIS The intense beams of neutron-rich ions produced by SPIRAL2 can be used to study the phenomena of vibration and rotation in highly exotic nuclei. PARIS (Photon Array for studies with Radioactive-Ion and Stable beams) employs cutting-edge technology intended for the detection of gamma radiation emitted by these nuclei. NEUTRON Detector, The Neutron Detector takes up the challenge for detection of neutrons and gamma radiation that is as efficient as possible while offering excellent discrimination between neutrons and gamma rays, in order to study the structure of rare neutron-rich nuclei. It is an ancillary detector to be used with experiments with stable or radioactive beams. AGATA (Advanced Gamma-ray Tracking Array) “a travelling detector” is a spherical array of gamma radiation detectors built by a large European collaboration. It is used in experiments with stable and radioactive heavy-ion beams, to study the structure of the nuclei. ACTAR (ACtive TARgets) is an R&D project to develop innovative systems to study the structure of extremely exotic nuclei with active targets in which nuclei are simultaneously produced and detected. SPIRAL2 beams, unique in the world, will be used to conduct hitherto impossible scientific studies. These new instruments dedicated to SPIRAL2, for the R&D phase, are supported by the EU FP7 trough the Preparatory Phase contract. Signatures of Memorandums of Understanding (MoU) related to the construction phase are expected by 2010-2011.

NATIONAL AND INTERNATIONAL COLLABORATION

SPIRAL2 is the result of the technical and scientific collaboration between numerous French, European and international laboratories. SPIRAL2 is financed by the CNRS Institut National de Physique Nucléaire et de Physique des Particules (IN2P3), the CEA Direction des Sciences de la Matière (DSM), the Region and local authorities of the region of Basse-Normandie, and with financial support of the European Union and international collaborations. The framework agreement concerning SPIRAL2 was signed on 4 September 2006 at GANIL.
SPIRAL2 is the national priority of the CNRS and the CEA in nuclear physics. At the start of the project, the following organisations were involved in France: At CNRS, 7 IN2P3 laboratories: CENBG at Bordeaux, CSNSM and IPN at Orsay, IPHC at Strasbourg, IPN at Lyon, LPC at Caen and LPSC at Grenoble, At CEA, 5 IRFU divisions of the Science Matter Division (DSM) at Saclay: SACM, SENAC, SIS, SEDI and SPhN; DAM and DEN directions and GANIL. Since the start of SPIRAL2 project numerous international collaborative agreements have already been signed or are under preparation. In particular, MoUs with GSI-FAIR (Germany), ISOLDE (CERN), Bulgaria, Israel, Rumania, the United Kingdom, JINR Dubna (Russia) and IMP (China). In addition, two European Associate laboratories (LEAs) have been set up with Italy and Poland and two international associated laboratories with India and Japan. After being selected in the ESFRI List [1], the SPIRAL2 project was granted “ a SPIRAL2 Preparatory Phase “ by the EC FP7 framework program with a budget of 3,9 M€ to set up an international consortium of research organisations allowing for the construction and operation of the facility as a European research infrastructure. The current legal and management structures of GANIL will be adapted to the international character of the SPIRAL2 project. Numerous critical technical issues still need to be addressed in order to construct the SPIRAL2 facility and associated instrumentation. Many European laboratories are collaborating in this project to meet these challenges. These high-tech developments also represent an excellent opportunity for funding agencies for research belonging to the international partners to participate in SPIRAL2.

Management of SPIRAL2 The project management is placed under the responsibility of a steering committee. The committee is constituted by the management of the Institut National de Physique Nucléaire et de Physique des Particules (IN2P3) of the Centre National à Recherche Scientifique (CNRS), the management of the Direction des Sciences de la Matière (DSM) of the Commissariat à l’Energie Atomique (CEA), and the management of GANIL. It is the controlling body for the Project and appoints the Project Leader and the Scientific Coordinator.. It relies on the recommendations of two international committees – one scientific (SAC), the other technical (TAC).

A SCIENTIFIC DYNAMO FOR THE BASSE-NORMANDIE REGION

The existence of GANIL and the construction of SPIRAL2 in Basse-Normandie have deeply influenced the scientific development of the region. The plateau situated in north of the city of Caen illustrates this, with the creation of a first class scientific hub around GANIL: ENSICAEN – the Ecole National Supérieur d’Ingénieurs de Caen – the IUT and UFR de Sciences on the University Campus 2, CYCERON – the biomedical research centre, etc. Cutting-edge technological advances, like the high-rate regional network VIKMAN, have developed in association with various laboratories. Since 1980, GANIL has given rise to spin-off companies, with the creation of PME: BIOPOR (1986-1990), GANELEC (1989-1993), Pantechnik (1991 up till today), and X-ION (1998 till today). An industry incubator “Normandie Incubation” has been set up to support the emergence of new projects. Since the launch of its activities in October 2000, Normandie Incubation has supported 47 projects which have already led to the creation of 28 businesses with 140 employees.

CREATION OF A RESEARCH POLE AROUND GANIL

A multidisciplinary scientific pole is progressively being built around GANIL forming the JULES HOROWITZ CAMPUS. It is composed of GANIL-SPIRAL1-SPIRA2 installations, CYCERON, a Medical imaging centre and medical research laboratory (with 90 permanent employees) and the CIRIL/CIMAP Interdisciplinary research laboratory with 77 permanent employees and 19 temporary employees.
GANIL, a major international player concerning research in nuclear physics, and its partners are an obvious choice in the “Regional nuclear excellence pole” project based on the Industry-Training-Research triptyque of Basse-Normandie. The creation of this cluster provides industries with access to high-quality heavy ion beams favour Transfer technologies to firms and encourage the creation of innovative high-tech companies.

FROM BASIC RESEARCH TO ECONOMIC DEVELOPMENT

Specifically oriented towards research in nuclear physics, GANIL is now opening larger avenues for other disciplines, ranging from astrophysics to radiobiology, material physics, etc. The CIMAP (Research Centre on Ions, Materials and Photonics) through its multidisciplinary research cluster installed at GANIL, named CIRIL, also part of the Jules Horowitz university campus, mainly conduct their research with beams from GANIL . Applied research is the logical consequence of these collaborations and extends to the socio-economic world. A partner for the regional economic world: project management, international collaborations and quality control bring the laboratory even closer to industry. The technological use of science has been in effect since 1980: appraisals, skill transfers and company spin-offs. GANIL is a founding member, together with the University of Caen Basse-Normandie and ENSICAEN (National Engineering School of Caen), of "Normandie Incubation", a structure intended to facilitate the creation of high-tech and innovative companies relying on research laboratories. With the scientific and technical expertise of its staff, GANIL acts as link enhancing the transfer of its teams' skills to other laboratories or industrial companies. Paving the way to industrial applications of ion beams, in fields such as testing and certification of components and electronic systems for space, or manufacturing of microporous membranes, GANIL is an essential site for French and international partners. To pool resources and improve their efficiency, CYCERON, ENSICAEN, GANIL and the University of Caen Lower Normandy (UCBN) signed on 6 January 2009 a collaborative agreement relating to the promotion of research.

GANIL, AN ECONOMIC DEVELOPMENT TOOL

253 direct jobs have been created through GANIL, half of them being high profile jobs for scientists and engineers, as well as 245 indirect jobs within a 30 km radius. In addition, by reinjection every year more than EUR 4 million as part of its operation, GANIL generates 111 jobs in the Region. The SPIRAL2 project will create another twenty or so direct jobs. The development of Normandie Incubation formed on the initiative of GANIL and its partners, has led to the creation of 28 companies, 140 jobs and a turnover since the start of EUR 11.5 million.

CONCLUSIONS

Nuclear physics has been revolutionized by the recent development of the ability to produce accelerated beams of radioactive nuclei. For the first time it will be possible to study reactions to produce the 6000 to 7000 nuclei we believe exist. SPIRAL2 is major expansion of the SPIRAL facility at GANIL, which will help maintain European leadership in ISOL (Isotope Separation On Line) development, aiming at two orders of magnitude increase of the secondary beams available for nuclear physics studies. The technical challenges of the high power accelerator, targets and experimental equipments will provide essential knowledge on the road toward EURISOL, the most advanced nuclear physics research facility presently imaginable and based on the ISOL principle. The scientific program, proposes the investigation of the most challenging nuclear and astrophysics questions aiming at the deeper understanding of the nature of matter. The SPIRAL2 facility –places Basse-Normandie in a strong position to host this future large European project EURISOL. During the European Commission’s sixth Framework Programme (FP6), GANIL has coordinated the efforts of a large international collaboration to define this ambitious project. The construction cost of SPIRAL2 amounts to 200 M€ (including personnel and contingency) shared by French founding agencies CNRS/IN2P3 and CEA/DSM, the Region of Basse Normandie and international partners. The first beams are expected to be delivered by SPIRAL2 in 2012. The full GANIL/SPIRAL1/SPIRAL2 facility will be operational by 2014 and will serve a community of about 800 users.

Acknowledgments

I would like to thank the whole GANIL-SPIRAL1-SPIRAL2 staff and community for allowing me to report here on their works and achievements. Special thanks to Dr. M. Lewitowicz and N. Alahri for a careful reading of the manuscript.

Sponsored by: Dr. Nicolas Alamanos, CEA, IRFU; F-91191 Gif-sur-Yvette, France, France

Reviewed by: Karsten Riisager, Aarhus University, Denmark.

Accepted on: 2010-07-07 21:42:24 GMT