GDR Neutrino, Annecy 2007 Beta-beam team1 Beta-beams M. Benedikt, A. Fabich and M. Lindroos, CERN on behalf of the Beta-beam Study Group BENE06/CARE06

GDR Neutrino, Annecy 2007 Beta-beam team2 Outline Beta-beam concept EURISOL DS scenario –Layout –Main issues on acceleration scheme –Physics reach Other scenarios –High-energy Beta-beams Study II Summary

GDR Neutrino, Annecy 2007 Beta-beam team3 Beta-beam principle Aim: production of (anti-)neutrino beams from the beta decay of radio-active ions circulating in a storage ring –Similar concept to the neutrino factory, but parent particle is a beta-active isotope instead of a muon. Beta-decay at rest –  spectrum well known from electron spectrum –Reaction energy Q typically of a few MeV Accelerated parent ion to relativistic  max –Boosted neutrino energy spectrum: E  2  Q –Forward focusing of neutrinos:  1/  Pure electron (anti-)neutrino beam! –NB: Depending on  + - or  - -decay we get a neutrino or anti-neutrino –Two (or more) different parent ions for neutrino and anti-neutrino beams Physics applications of a beta-beam –Primarily neutrino oscillation physics and CP-violation –Cross-sections of neutrino-nucleus interaction  =100

GDR Neutrino, Annecy 2007 Beta-beam team4 Guideline to -beam scenarios based on radio-active ions Low-energy beta-beam: relativistic  < 20 –Physics case: neutrino scattering Medium energy beta-beam:  100 –E.g. EURISOL DS –Today the only detailed study of a beta-beam accelerator complex High energy beta-beam:  >350 –Take advantage of increased interaction cross-section of neutrinos Monochromatic neutrino-beam –Take advantage of electron-capture process High-Q value beta-beam:  100 Accelerator physicists together with neutrino physicists defined the accelerator case of  =100/100 to be studied first (EURISOL DS).

GDR Neutrino, Annecy 2007 Beta-beam team5 The EURISOL scenario Based on CERN boundaries Ion choice: 6 He and 18 Ne Relativistic gamma=100/100 –SPS allows maximum of 150 ( 6 He) or 250 ( 18 Ne) –Gamma choice optimized for physics reach Based on existing technology and machines –Ion production through ISOL technique –Post acceleration: ECR, linac –Rapid cycling synchrotron –Use of existing machines: PS and SPS Achieve an annual neutrino rate of either –2.9*10 18 anti-neutrinos from 6 He –Or neutrinos from 18 Ne Once we have thoroughly studied the EURISOL scenario, we can “easily” extrapolate to other cases. EURISOL study could serve as a reference. EURISOL scenario

GDR Neutrino, Annecy 2007 Beta-beam team6 A new approach for the production Beam cooling with ionisation losses – C. Rubbia, A Ferrari, Y. Kadi and V. Vlachoudis in NIM A, In press “Many other applications in a number of different fields may also take profit of intense beams of radioactive ions.” 7 Li(d,p) 8 Li 6 Li( 3 He,n) 8 B 7 Li 6 Li Missed opportunities See also: Development of FFAG accelerators and their applications for intense secondary particle production, Y. Mori, NIM A562(2006)591

GDR Neutrino, Annecy 2007 Beta-beam team7 Transverse cooling in paper by Carlo Rubbia et al. “ In these conditions, like in the similar case of the synchrotron radiation, the transverse emittance will converge to zero. In the case of ionisation cooling, a finite equilibrium emittance is due to the presence of the multiple Coulomb scattering.”

GDR Neutrino, Annecy 2007 Beta-beam team8 Longitudinal cooling in paper by Carlo Rubbia et al. “In order to introduce a change in the dU/dE term — making it positive in order to achieve longitudinal cooling — the gas target may be located in a point of the lattice with a chromatic dispersion. The thickness of the foil must be wedge-shaped in order to introduce an appropriate energy loss change, proportionally to the displacement from the equilibrium orbit position.” Number of turns 1)Without wedge, dU/dE<0 2)Wedge with dU/dE=0, no longitudinal cooling 3)Wedge with dU/dE= )Electrons, cooling through synchrotron radiation

GDR Neutrino, Annecy 2007 Beta-beam team9 Inverse kinematics production and ionisation parameters in paper by Carlo Rubbia et al. 7 Li(d,p) 8 Li 6 Li( 3 He,n) 8 B

GDR Neutrino, Annecy 2007 Beta-beam team10 Collection in paper by Carlo Rubbia et al. “The technique of using very thin targets in order to produce secondary neutral beams has been in use for many years. Probably the best known and most successful source of radioactive beams is ISOLDE.”

GDR Neutrino, Annecy 2007 Beta-beam team11 Reactions to study for our application 20 Ne(p,t) 18 Ne –H.Backhausen et al, RCA,29(1981)1 16 O( 3 He,n) 18 Ne –V.Tatischeff et al, PRC,68(2003) C(CO 2, 6 He) 18 Ne? –K.I.Hahn et al, PRC,54(1996) Li(T,A) 6 He

GDR Neutrino, Annecy 2007 Beta-beam team12 Collection in a gas cell IGISOL technique (Ion Guide) Figure from Juha Aysto, Nucl.Phys. A693(2001)477 At 200 Torr of 4 He, 10% efficiency, space charge limit at 10 8 ions cm -3 (peak ions cm -3 ?), Private communication Ari Jokinen BEAM Gas cell Extraction Cool gas in

GDR Neutrino, Annecy 2007 Beta-beam team13 What about the intensities? –Cross section similar or larger compared to those studied in detail in C. Rubbia et al.’s paper –Heavier ions in the ring will require further beam dynamics study –Space charge effects will set the limit for the IGISOL type device. With a 1000 cm 3 gas cell, is ions s -1 realistic? –Collection with foils as proposed by C. Rubia et al?

GDR Neutrino, Annecy 2007 Beta-beam team14 Intensity evolution during acceleration Cycle optimized for neutrino rate towards the detector 30% of first 6 He bunch injected are reaching decay ring Overall only 50% ( 6 He) and 80% ( 18 Ne) reach decay ring Normalization –Single bunch intensity to maximum/bunch –Total intensity to total number accumulated in RCS Bunch 20 th 15 th 10 th 5th 1st total

GDR Neutrino, Annecy 2007 Beta-beam team15 Dynamic vacuum Decay losses cause degradation of the vacuum due to desorption from the vacuum chamber The current study includes the PS, which does not have an optimized lattice for unstable ion transport and has no collimation system –The dynamic vacuum degrades to 3*10 -8 Pa in steady state ( 6 He) An optimized lattice with collimation system would improve the situation by more than an order of magnitude. P. Spiller et al., GSI C. Omet et al., GSI

GDR Neutrino, Annecy 2007 Beta-beam team16 Collimation and absorption Merging: –increases longitudinal emittance –Ions pushed outside longitudinal acceptance  momentum collimation in straight section Decay product –Daughter ion occurring continuously along decay ring –To be avoided: magnet quenching: reduce particle deposition (average 10 W/m) Uncontrolled activation –Arcs: Lattice optimized for absorber system OR open mid-plane dipoles – Straight section: Ion extraction et each end s (m) Deposited Power (W/m) Optical functions (m) primary collimator A. Chance et al., CEA Saclay

GDR Neutrino, Annecy 2007 Beta-beam team17 Decay ring magnet protection Absorbers checked (in beam pipe): No absorber, Carbon, Iron, Tungsten Theis C., et al.: "Interactive three dimensional visualization and creation of geometries for Monte Carlo calculations", Nuclear Instruments and Methods in Physics Research A 562, pp (2006).

GDR Neutrino, Annecy 2007 Beta-beam team18 Longitudinal penetration in coil No absorber Carbon Stainless Steel Coil Abs Coil Abs Power deposited in dipole

GDR Neutrino, Annecy 2007 Beta-beam team19 Impedance, 340 steps! Below 2.3 GHz, a total of 340 steps (170 absorbers) would add up to 0.5  H, which seems really high. Im{Z}/  f/GHz lowest cut-off (2.3 GHz) Impedance of one step (diameter 6 to 10 cm or 10 to 6 cm): L = 1.53 nH

GDR Neutrino, Annecy 2007 Beta-beam team20 Possible new solution 60 degrees Cu or SS Cu or SS sheets with 60 degrees opening on the sides Top view, midplane Between dipoles In dipoles beams y [m]

GDR Neutrino, Annecy 2007 Beta-beam team21 Intra Beam scattering, growth times Results obtained with Mad-8 6 He 18 Ne

GDR Neutrino, Annecy 2007 Beta-beam team22 Objectives A High Intensity Neutrino Oscillation Facility in Europe –CDR for the three main options: Neutrino Factory, Beta- beam and Super-beam –Focus on potential showstoppers –Preliminary costing to permit a fair comparison before the end of 2011 taking into account the latest results from running oscillation experiments –Total target for requested EU contribution: 4 Meuro 1 MEuro each for SB, NF and BB WPs 1 MEuro to be shared between Mgt, Phys and Detectors WPs 4 year project

GDR Neutrino, Annecy 2007 Beta-beam team23 Beta-beam WPs WP leader: Michael Benedikt, CERN Deputy: Adrian Fabich, CERN Objective: –Coordination task: CERN leads the task, is responsible for the parameter list and for the overall coherence of the baseline scenario. –Review task: The work will start with a review of the base line design for the new isotopes 8 B and 8 Li performed by CERN and CEA. –Bunching task: The work at LPSC with the 60 GHz ECR source for bunching studies of 6He and 18Ne started within EURISOL DS will continue with the objective of reaching the high efficiencies needed for the beta-beam.. Furthermore, a study and first tests will be done at LPSC of necessary modification to bunch 8 Li and 8 B. –Cross sections and collection device task: The cross section for the reaction channels of interest will be (re-)measured and a prototype for the collection device will be built and tested with stable beams at LLN. –Superconducting magnets, magnet protection and collimation task: A pre-study of possible lay-out for superconducting dipoles for the beta-beam will be done at CERN and a baseline design will be identified. The work started on beam collimation and magnet protection in EURISOL DS will be adapated for 8Li and 8B at CERN and CEA Participating institutes: CERN, UCL, IN2P3 (LPSC), CEA Additional partners: INFN (LNL), TRIUMF, RAS/IAP, Princeton, ANL

GDR Neutrino, Annecy 2007 Beta-beam team24 Management structure STEERING COMMITTEE 1 representative of each Participant + Management Board and representatives of ECFA, ESGARD, BENE, IDS, EURISOL (all ex-officio) 1 meeting/year MANAGEMENT BOARD Project Leader + 2 Members MANAGEMENT SUPPORT COORDINATION BOARD Management Board + Task Leaders + Coordinators of related EU activities (ex-officio) 2-3 Meetings/year INTERNATIONAL ADVISORY PANEL 3 Members – 1 Meeting/year ANNUAL PARTICIPANT MEETING 1 Meeting/year WP Nufact WP BetaB WP MGT WP Detec WP Phys WP SuperB

GDR Neutrino, Annecy 2007 Beta-beam team25 Annual participants meeting Annual meeting: –Monitoring of progress and coherence of the study by SC and IAP members –Annual review of project deliverables and milestones –Bringing the European Neutrino oscillation community together Physics community and machine community

GDR Neutrino, Annecy 2007 Beta-beam team26 Summary Beta-beam accelerator complex is a very high technical challenge due to high ion intensities Activation Space charge –So far it looks technically feasible. The physics reach for the EURISOL DS scenario is competitive for   >1 O. –Usefulness depends on the short/mid-term findings by other neutrino search facilities. The physics made possible with the new production concept proposed by Rubbia and Mori needs to be explored We need a study II –Plenty of new ideas! Acknowledgment of the input given by M. Benedikt, A. Jansson, M. Mezzetto, E. Wildner, beta-beam task group and related EURISOL tasks