 Benasque The Beta-beam Mats Lindroos on behalf of The beta-beam study group

 Benasque Collaborators The beta-beam study group: –CEA, France: Jacques Bouchez, Saclay, Paris Olivier Napoly, Saclay, Paris Jacques Payet, Saclay, Paris –CERN, Switzerland: Michael Benedikt, AB Peter Butler, EP Roland Garoby, AB Steven Hancock, AB Ulli Koester, EP Mats Lindroos, AB Matteo Magistris, TIS Thomas Nilsson, EP Fredrik Wenander, AB –Geneva University, Switzerland: Alain Blondel Simone Gilardoni –GSI, Germany: Oliver Boine-Frankenheim B. Franzke R. Hollinger Markus Steck Peter Spiller Helmuth Weick –IFIC, Valencia: Jordi Burguet, Juan-Jose Gomez-Cadenas, Pilar Hernandez, Jose Bernabeu –IN2P3, France: Bernard Laune, Orsay, Paris Alex Mueller, Orsay, Paris Pascal Sortais, Grenoble Antonio Villari, GANIL, CAEN Cristina Volpe, Orsay, Paris –INFN, Italy: Alberto Facco, Legnaro Mauro Mezzetto, Padua Vittorio Palladino, Napoli Andrea Pisent, Legnaro Piero Zucchelli, Sezione di Ferrara –Louvain-la-neuve, Belgium: Thierry Delbar Guido Ryckewaert –UK: Marielle Chartier, Liverpool university Chris Prior, RAL and Oxford university –Uppsala university, The Svedberg laboratory, Sweden: Dag Reistad –Associate: Rick Baartman, TRIUMF, Vancouver, Canada Andreas Jansson, Fermi lab, USA, Mike Zisman, LBL, USA

 Benasque The beta-beam Idea by Piero Zucchelli –A novel concept for a neutrino factory: the beta-beam, Phys. Let. B, 532 (2002) The CERN base line scenario –Avoid anything that requires a “technology jump” which would cost time and money (and be risky) –Make use of a maximum of the existing infrastructure –If possible find an “existing” detector site

 Benasque CERN:  -beam baseline scenario PS Decay Ring ISOL target & Ion source SPL Cyclotrons, linac or FFAG Decay ring Brho = 1500 Tm B = 5 T L ss = 2500 m SPS ECR Rapid cycling synchrotron Nuclear Physics

 Benasque Target values for the decay ring 18 Neon 10+ (single target) –In decay ring: 4.5x10 12 ions –Energy: 55 GeV/u –Rel. gamma: 60 –Rigidity: 335 Tm The neutrino beam at the experiment will have the “time stamp” of the circulating beam in the decay ring. The beam has to be concentrated to as few and as short bunches as possible to aim for a duty factor of Helium 2+ –In Decay ring: 1.0x10 14 ions –Energy: 139 GeV/u –Rel. gamma: 150 –Rigidity: 1500 Tm

 Benasque SPL, ISOL and ECR Objective: Production, ionization and pre-bunching of ions Challenges: Production of ions with realistic driver beam current –Target deterioration Accumulation, ionization and bunching of high currents at very low energies SPL ISOL Target + ECR Linac, cyclotron or FFAG Rapid cycling synchrotron PSSPS Decay ring

 Benasque ISOL production 1 GeV p p n U F r + spallation 1 1 L i X + + fragmentation C s Y + + fission

 Benasque Layout very similar to planned EURISOL converter target aiming for fissions per s. 6 He production by 9 Be(n,  ) Converter technology: ( J. Nolen, NPA 701 (2002) 312c ) Courtesy of Will Talbert, Mahlon Wilson (Los Alamaos) and Dave Ross (TRIUMF)

 Benasque Mercury jet converter H.Ravn, U.Koester, J.Lettry, S.Gardoni, A.Fabich

 Benasque Spallation of close-by target nuclides: 18,19 Ne from MgO and 34,35 Ar in CaO –Production rate for 18 Ne is 1x10 12 s -1 (with 2.2 GeV 100  A proton beam, cross-sections of some mb and a 1 m long oxide target of 10% theoretical density) – 19 Ne can be produced with one order of magnitude higher intensity but the half life is 17 seconds! Production of  + emitters

 Benasque GHz « ECR Duoplasmatron » for pre-bunching of gaseous RIB Very high density magnetized plasma n e ~ cm – 3.0 T pulsed coils or SC coils GHz / KW 10 –200 µs / = 6-3 mm optical axial coupling optical radial coupling (if gas only)  1-3 mm 100 KV extraction UHF window or « glass » chamber (?) Target Rapid pulsed valve 20 – 100 µs 20 – 200 mA to ions per bunch with high efficiency Very small plasma chamber  ~ 20 mm / L ~ 5 cm Arbitrary distance if gas Moriond meeting: Pascal Sortais et al. LPSC-Grenoble

 Benasque Low-energy stage Objective: Fast acceleration of ions and injection Acceleration of 16 batches to 100 MeV/u SPL ISOL Target + ECR Linac, cyclotron or FFAG Rapid cycling synchrotron PSSPS Decay ring

 Benasque Rapid Cycling Synchrotron Objective: Accumulation, bunching (h=1), acceleration and injection into PS Challenges: High radioactive activation of ring Efficiency and maximum acceptable time for injection process –Charge exchange injection –Multiturn injection Electron cooling or transverse feedback system to counteract beam blow-up? SPL ISOL Target + ECR Linac, cyclotron or FFAG Rapid cycling synchrotron PSSPS Decay ring

 Benasque PS Accumulation of 16 bunches at 300 MeV/u Acceleration to  =9.2, merging to 8 bunches and injection into the SPS Question marks: –High radioactive activation of ring –Space charge bottleneck at SPS injection will require a transverse emittance blow-up SPL ISOL Target + ECR Linac, cyclotron or FFAG Fast cycling synchrotron PS SPS Decay ring

 Benasque Overview: Accumulation Sequential filling of 16 buckets in the PS from the storage ring

 Benasque SPS Objective: Acceleration of 8 bunches of 6 He(2+) to  =150 –Acceleration to near transition with a new 40 MHz RF system –Transfer of particles to the existing 200 MHz RF system –Acceleration to top energy with the 200 MHz RF system Ejection in batches of four to the decay ring Challenges: Transverse acceptance SPL ISOL Target + ECR Linac, cyclotron or FFAG Fast cycling synchrotron PS SPS Decay ring

 Benasque Decay ring Objective: Injection of 4 off-momentum bunches on a matched dispersion trajectory Rotation with a quarter turn in longitudinal phase space Asymmetric bunch merging of fresh bunches with particles already in the ring SPL ISOL Target + ECR Linac, cyclotron or FFAG Fast cycling synchrotron PSSPS Decay ring

 Benasque Injection into the decay ring Bunch merging requires fresh bunch to be injected at ~10 ns from stack! –Conventional injection with fast elements is excluded. Off-momentum injection on a matched dispersion trajectory. Rotate the fresh bunch in longitudinal phase space by ¼ turn into starting configuration for bunch merging. –Relaxed time requirements on injection elements: fast bump brings the orbit close to injection septum, after injection the bump has to collapse within 1 turn in the decay ring (~20  s). –Maximum flexibility for adjusting the relative distance bunch to stack on ns time scale.

 Benasque Horizontal aperture layout Assumed machine and beam parameters: –Dispersion:D hor = 10 m –Beta-function:  hor = 20 √m –Moment. spread stack:  p/p = ±1.0x10 -3 (full) –Moment. spread bunch:  p/p = ± 2.0x10 -4 (full) –Emit. (stack, bunch):  geom = 0.6  m Septum & alignment 10 mm Stack: ± 10mm momentum ± 4 mm emittance Beam: ± 2 mm momentum ± 4 mm emittance Required separation: 30 mm, corresponds to 3x10 -3 off-momentum. Required bump: 22 mm Central orbit undisplaced M. Benedikt

 Benasque Full scale simulation with SPS as model Simulation conditions: –Single bunch after injection and ¼ turn rotation. –Stacking again and again until steady state is reached. –Each repetition, a part of the stack (corresponding to  -decay) is removed. Results: –Steady state intensity was ~85 % of theoretical value (for 100% effective merging). –Final stack intensity is ~10 times the bunch intensity (~15 effective mergings). –Moderate voltage of 10 MV is sufficient for 40 and 80 MHz systems for an incoming bunch of < 1 eVs.

 Benasque SPS Stacking in the Decay ring Ejection to matched dispersion trajectory Asymmetric bunch merging SPS

 Benasque Asymmetric bunch merging

 Benasque Asymmetric bunch merging (S. Hancock, M. Benedikt and J,- L.Vallet, A proof of principle of asymmteric bunch pair merging, AB- note MD)

 Benasque Decay losses Losses during acceleration are being studied: –Full FLUKA simulations in progress for all stages (M. Magistris and M. Silari, Parameters of radiological interest for a beta-beam decay ring, TIS RP-TN) –Preliminary results: Can be managed in low energy part PS will be heavily activated –New fast cycling PS? SPS OK! Full FLUKA simulations of decay ring losses: –Tritium and Sodium production surrounding rock well below national limits –Reasonable requirements of concreting of tunnel walls to enable decommissioning of the tunnel and fixation of Tritium and Sodium

 Benasque Decay losses Acceleration losses: 6 He (T 1/2 =0.8 s) 18 Ne (T 1/2 =1.67 s) Accumulation<47 mW/m<2.9 mW/m PS1.2 W/m 90 mW/m SPS0.41 W/m32 mW/m Decay ring8.9 W/m0.6 W/m A. Jansson

 Benasque How bad is 9 W/m? For comparison, a 50 GeV muon storage ring proposed for FNAL would dissipate 48 W/m in the 6T superconducting magnets. Using a tungsten liner to –reduce peak heat load for magnet to 9 W/m. –reduce peak power density in superconductor (to below 1mW/g) –Reduce activation to acceptable levels Heat load may be OK for superconductor.

 Benasque SC magnets Dipoles can be built with no coils in the path of the decaying particles to minimize peak power density in superconductor –The losses have been simulated and one possible dipole design has been proposed S. Russenschuck, CERN

 Benasque Tunnels and Magnets Civil engineering costs: Estimate of 400 MCHF for 1.3% incline (13.9 mrad) –Ringlenth: 6850 m, Radius=300 m, Straight sections=2500 m Magnet cost: First estimate at 100 MCHF FLUKA simulated losses in surrounding rock (no public health implications)

 Benasque Intensities Stage 6 He 18 Ne (single target) From ECR source: 2.0x10 13 ions per second0.8x10 11 ions per second Storage ring: 1.0x10 12 ions per bunch4.1x10 10 ions per bunch Fast cycling synch: 1.0x10 12 ion per bunch4.1x10 10 ion per bunch PS after acceleration: 1.0x10 13 ions per batch5.2x10 11 ions per batch SPS after acceleration: 0.9x10 13 ions per batch4.9x10 11 ions per batch Decay ring: 2.0x10 14 ions in four 10 ns long bunch 9.1x10 12 ions in four 10 ns long bunch Only  -decay losses accounted for, add efficiency losses (50%)

 Benasque CERN to FREJUS Geneve Italy 130km 40kt  400kt CERN CERN 2.2GeV, 50Hz, 2.3x10 14 p /pulse  4MW Now under R&D phase

 Benasque The Super Beam

 Benasque THE PROPOSAL C. Volpe, hep-ph/ To appear in Journ. Phys. G. 30(2004)L1 PHYSICS POTENTIAL Neutrino-nucleus interaction studies for particle, nuclear physics, astrophysics (nucleosynthesis). e e C N Neutrino properties, like magnetic moment. LOW-ENERGY BETA-BEAMS boost 6 He Beta-beam To exploit the beta-beam concept to produce intense and pure low-energy neutrino beams. A „BETA-BEAM“ FACILITY FOR LOW-ENERGY NEUTRINOS.

 Benasque Prospects for the neutrino magnetic moment G.C. McLaughlin and C. Volpe, hep-ph/ , to appear in Phys. Lett. B  B 5 X  B e -e events with beta-beams (10 15 /s) with a 4  low threshold detector. 6 He 6 Li+e+ e Q   MeV e e e e PRESENT LIMIT :  < 1.0 x  B. 6 He THE LIMIT CAN BE IMPROVED BY ONE ORDER of MAGNITUDE ( a few x  B ).  =0

 Benasque Neutrino-nucleus Interaction Rates At a Low-energy Beta-beam Facility J. Serreau and C. Volpe, hep-ph/ , submitted to Phys. Rev. D. Small RingLarge Ring e Pb e + Nucleus e + 16 O e + D Events/year for  =14 Small Ring : L ss = 150 m, L tot = 450 m. Large Ring : L ss = 2.5 km, L tot = 7.5 km Neutrino Fluxes INTERESTING INTERACTION RATES CAN BE OBTAINED.

 Benasque Possible sites CERN GANIL (EURISOL) GSI Intensities Detectors  /s 1 44 /s /s  and Close detector 4  and Close detector Autin et al, J.Phys. (2003). H. Weick (GSI) A. Villari (GANIL) CERN IS A UNIQUE SITE BOTH FOR THE -INTENSITIES AND THE -ENERGIES.

 Benasque R&D (improvements) Production of RIB (intensity) –Simulations (GEANT, FLUKA) –Target design, only 200 kW primary proton beam in present design Acceleration (cost) –FFAG versa linac/storage ring/RCS –High gamma option Tracking studies (intensity) –Loss management Superconducting dipoles (  of neutrinos) –Pulsed for new PS/SPS (GSI FAIR) –High field dipoles for decay ring to reduce arc length –Radiation hardness (Super FRS) SPL ISOL Target + ECR Linac, cyclotron or FFAG Rapid cycling synchrotron PSSPS Decay ring

 Benasque Comments & speculations: Ne and He in decay ring simultaneously Possible gain in counting time and reduction of systematic errors –Cycle time for each ion type doubles! Requiring  =(60)150 for He will at equal rigidity result in a  =(100)250 for Ne –Physics? –Detector simulation should give “best” compromise Requiring equal revolution time will result in a  R of 97(16) mm (  =300 m) –Insertion in one straight section to compensate

 Benasque Comments & sepculations: Accumulation Ne + He in DECAY RING 6 He 8 s SPS cycling 6 He 16 s SPS cycling Accumulation (multiplication) factor Time (s) Requires larger long. Acceptance!

 Benasque Comments & sepculations: Accumulation Ne + He before acceleration Base line scenario assumes accumulation of 16 bunches for one second at 300 MeV/u (PS) for both He and Ne Optimization assuming fixed ECR intensity (out): –Longer accumulation –SPS accumulation Accumulation (PS or SPS) Production and bunching (ISOL and ECR) 1 s in baseline Number of ions constant from ECR source

 Benasque Comments & speculations: Accumulation before acceleration Number of fills Increase of intensity SPS: He, one fill of 1 unit of ions every 1.2 s SPS: Ne, one fill of 1 unit of ions every 1.2 s PS: Ne, one fill of 1 unit of ions every 1/16 s PS: He one fill of 1 unit of ions every 1/16 s PS Baseline

 Benasque Comments & speculations: Wasted time? Production PS SPS Decay ring Ramp time PS Time (s)0 8 Wasted time? Ramp time SPS Reset time SPS

 Benasque Comments & speculations: Higher Gamma? Requires either a larger bending radius or a higher magnetic field for the decay ring, the baseline circumference is 6885 m and has a bending radius (  ) of 300 m: At  =500 ( 6 He),  =935 m at B=5 T To keep the percentage of straight section the same as the baseline the ring would become 21.4 km long Alternatively new dipoles:  =300 m at B=15.6 T Or LHC type dipoles at B=10 T and  =468 m with a circumference of 7794 m Requires an upgrade of SPS or ramping of the decay ring –SPS upgrade expensive and time consuming –Ramping of decay ring requires less frequent fills and higher total intensity

 Benasque Comments & speculations: Duty factor (or empty buckets) The baseline delivers a neutrino beam with an energy badly troubled by atmospheric background –Duty factor= , 4 buckets out of 919 possible filled —› 10 ns total bunch length –At  =500 the duty factor can be increased to (P. Hernandez), 92 buckets filled or 23 times the intensity theoretically, can that be realised?

 Benasque Comments & speculations: Electron Capture, Monochromatic beams Nuclei that only decay by electron capture generally have a long half-life (low Q value, <1022 keV) –Some possible candidates: 110 Sn (4.1 h half life) and 164 Yb (75.8 min half life) –Maybe possible if very high intensities can be collected in the decay ring and a high duty factor can be accepted (0.1) High gamma with ramping of the decay ring? For the baseline: With  =259, assuming ions in the decay ring and a duty factor of 0.1 there would be neutrinos per second at 259x0.326 MeV= MeV, is that useful?

 Benasque Design Study EURISOL Beta-beam Coordination Beta-beam parameter group Above 100 MeV/u Targets 60 GHz ECR Low energy beta-beam And many more… USERS Frejus Gran Sasso High Gamma Astro-Physics Nuclear Physics ( , intensity and duty factor) OTHER LABS TRIUMF FFAG Tracking Collimators US study Neutrino Factory DS Conceptual Design # with price ### M€

 Benasque Superbeam & Beta Beam cost estimates (NUFACT02)

 Benasque boost 6 He Beta-beam “The chances of a neutrino actually hitting something as it travels through all this emptiness are roughly comparable to that of dropping a ball bearing from a cruising 747* and hitting, say an egg sandwich”, Douglas Adams, Mostly Harmless, Chapter 3 *) European A380, Prototype will fly in 2005 EURISOL Design Study, when will the beta-beam fly? A boost for radioactive nuclear beams A boost for neutrino physics A EURISOL/beta-beam facility at CERN!