1. 8-10 January 2014 - Paris Diderot University High Power Protons Drivers for Beams in Europe R. Garoby [using material from M. Dracos (CNRS), T. Ekelof (Uppsala), M. Jensen (ESS), D. McGinnis (ESS), J. Thomasson (ISIS), O. Capatina, I. Efthymiopoulos, E. Montesinos, E. Shaposhnikova, Y. Papaphilippou, V. Parma, …]

2. R. G. – 9/01/20142 ICFA EU Jan. 2014 - Paris A proton driver is necessary for most types of neutrino facilities and it can be used (and present ones have been built) for other purposes. A Neutrino Factory is the most demanding application*, although the proton driver remains a modest part of the whole facility. Two types of set-ups are favoured: Ring-based SRF linac-based. * IDS NF specifications: - 4 MW proton beam power - Proton kinetic energy 5 – 15 GeV - RMS bunch length 1 – 3 ns - 50 Hz repetition rate - 3 bunches, extracted > 80 µs apart Reference IDS NF Design

3. RAL CERN ESS Plans for Proton Drivers at:

4. R. G. – 9/01/20144 ICFA EU Jan. 2014 - Paris Optimised double harmonic RF system accelerating 300 µA in the synchrotron 4/5 pulse pairs to TS-1 (192 kW) and 1/5 pulse pairs to TS-2 (48 kW) Must keep beam to TS-2 for the foreseeable future ISIS plans (1/9) Current (upgraded) ISIS (0.24 MW)

5. R. G. – 9/01/20145 ICFA EU Jan. 2014 - Paris Further developments of the ISIS accelerator and target stations are possible with each stage giving of order a factor 2 enhancement of the neutron source characteristics 0)Linac refurbishment and TS-1 upgrade 1)Linac upgrade optimised to maximise potential of earlier TS-1 upgrade 2)~3.3 GeV booster synchrotron: MW Target 3)800 MeV direct injections to booster synchrotron: 2 – 5 MW Target overlap with NF proton driver MW upgrade scenarios ISIS plans (2/9)

6. R. G. – 9/01/20146 ICFA EU Jan. 2014 - Paris 2) Based on a ~3.3 GeV RCS fed by bucket-to- bucket transfer from ISIS 800 MeV synchrotron (1MW, perhaps more) 3) RCS design also accommodates multi-turn charge exchange injection to facilitate a further upgrade path where the RCS is fed directly from an 800 MeV linac (2 – 5 MW) 1) Replace ISIS linac with a new, higher energy (up to 180 MeV) linac MW upgrade scenarios ISIS plans (3/9)

7. R. G. – 9/01/20147 ICFA EU Jan. 2014 - Paris Energy0.8 – 3.2 GeV Rep Rate50 Hz C, R/R 0 367.6 m, 9/4 Gamma-T7.2 h9 f rf sweep6.1-7.1 MHz Peak V rf ~ 750 kV Peak K sc ~ 0.1  l per bunch ~ 1.5 eV s B[t]B[t]sinusoidal 5SP RCS Ring MW upgrade: «typical» 3.2 GeV RCS ISIS plans (4/9) Main RCS characteristics

8. R. G. – 9/01/20148 ICFA EU Jan. 2014 - Paris Beam power for 2 MW, 30 Hz, 3.2 GeV RCS0.5 MW Beam pulse current before MEBT chopping43.0 mA Beam pulse current after MEBT chopping30.0 mA Number of injected turns for 370 m RCS~500 turns Beam pulse duration at the 30 Hz rep rate~730.0 μs Duty cycle for the extent of the beam pulse~2.2 % MEBT(out) normalised rms emittances0.30, 0.42 (π) mm mr Main characteristics MW upgrade: 800 MeV linac ISIS plans (5/9) Draft architecture

9. R. G. – 9/01/20149 ICFA EU Jan. 2014 - Paris Based on MW ISIS upgrade with 800 MeV Linac and 3.2 (~3.3) GeV RCS Assumes a sharing of the beam power at 3.2 GeV between the two facilities Both facilities can have the same ion source, RFQ, chopper, linac, H − injection, accumulation and acceleration to 3.2 GeV Requires additional RCS machine in order to meet the power and energy needs of the Neutrino Factory Common Proton Driver for neutrons and NF ISIS plans (6/9)

10. R. G. – 9/01/201410 ICFA EU Jan. 2014 - Paris Bunches will be transfered from the booster RCS at ~ 3.2 GeV, 50 Hz 2 bunches, 3.9  10 13 protons/bunch, 6.4 GeV 3 MW to ISIS 3 bunches, 2.2  10 13 protons/bunch, 7.7 GeV 3⅓ MW to ISIS Assume 4 – 5 MW from booster RCS, and 4MW required from NF proton driver : 3 bunches, 3.9  10 13 protons/bunch, 4.3 GeV 2 MW to ISIS NF ISIS 5 MW 3 bunches, 1.76  10 13 protons/bunch, 9.6 GeV 2⅔ MW to ISIS 4 MW Common Proton Driver: RCS beam sharing ISIS plans (7/9)

11. R. G. – 9/01/201411 ICFA EU Jan. 2014 - Paris Number of superperiods6 Circumference694.352 m Harmonic number17 RF frequency7.149 – 7.311 MHz Betatron tunes ( Q H, Q V )(8.72, 7.82) Gamma transition13.37 (flexible) Beam power at 9.6 GeV4 MW for 3 bunches Injection energy3.2 GeV Extraction energy9.6 GeV RF voltage per turn≈ 3.7 MW Repetition rate50 Hz Max B field in dipoles1.2 T Length of long drift14 m Present-day, cost-effective RCS technology Only three quadrupole families Allows a flexible choice of gamma transition Parameters of 3.2 – 9.6 GeV RCS Common Proton Driver: 2 nd RCS design ISIS plans (8/9)

12. R. G. – 9/01/201412 ICFA EU Jan. 2014 - Paris High power front end (FETS) RF Systems Stripping Foils Diagnostics Targets Kickers etc. To realise ISIS MW upgrades, NF and generic high power proton driver development, common hardware R&D will be necessary in key areas: In the neutron factory context SNS and J-PARC have dealt with many of these issues during facility commissioning and we have a watching brief for all of these Active programmes in some specific areas MW Proton Driver: Necessary R § D ISIS plans (9/9)

13. RAL CERN ESS Plans for Proton Drivers at:

14. R. G. – 9/01/201414 ICFA EU Jan. 2014 - Paris CERN accelerator complex

15. R. G. – 9/01/201415 ICFA EU Jan. 2014 - Paris PSB SPS Linac4 LP-SPL PS LHC 160 MeV 1.4 GeV 4 GeV 26 GeV 50 GeV 450 GeV 7 TeV Linac2 50 MeV Proton flux / Beam power PS2 Present Typical Future 1978 1975 1959 2008 LP-SPL: Low Power-Superconducting Proton Linac PS2:High Energy PS (~ 5 to 50 GeV – 0.3 Hz) PS2 SPL LINAC4 SPS PS Reminder: LHC injectors' renovation plan until 2010

16. R. G. – 9/01/201416 ICFA EU Jan. 2014 - Paris Present plans for low/medium energy proton accelerators 1.LHC Injectors Upgrade Project («LIU» concerning Linac4, PSB, PS and SPS): – upgrades for increased beam brightness and intensity for LHC, – extensive consolidation for maximum reliability until beyond 2035 2.Contribution to the LAGUNA-LBNO Design Study (on-going studies): – study of maximum SPS beam power after LIU (goal ~0.7 MW at 400 GeV), – CDR of a High Power PS («HP-PS») (goal ~2 MW at 50-75 GeV), – study of accumulator and compressor for an SPL-based driver (goal ~4 MW at 5 GeV) 3.R&D on crucial components for a High Power Superconducting Proton Linac («SPL»): – construction of sc cavities and prototype cryomodule, – upgrade of infrastructure (workshops, assembly and test places)

17. R. G. – 9/01/201417 ICFA EU Jan. 2014 - Paris The LHC Injectors’ Upgrade Project Construction of Linac4 (160MeV H - ) for replacing Linac2 (50 MeV H + ) and as potential future front end for an SPL PSB upgrade with 160 MeV H - injection, 2 GeV maximum energy (1.4 GeV today) and new RF for doubling intensity and brightness per pulse PS upgrade with 2 GeV injection energy, increased shielding and improved beam stability for higher brightness, reduced beam loss and better radiation safety SPS upgrade with new optics, doubled RF power, radio-protection improvements, e- cloud mitigation measures for reaching HL-LHC brightness and better radiation safety LHC SPS PS PSB Experiments & Test Beams LINAC 4 160 MeV

18. R. G. – 9/01/201418 ICFA EU Jan. 2014 - Paris LAGUNA-LBNO: SPS potential beam power OperationSPS recordAfter LIU (2020) UserLHCCNGSLHCCNGSLHCCN2PY SPS beam energy [GeV]450400450400450400 bunch spacing [ns]505255 5 bunch intensity [10 11 ]1.60.1051.30.132.20.17 number of bunches144420028842002884200 SPS beam intensity [10 13 ]2.34.43.755.36.357.0* PS beam intensity [10 13 ]0.62.31.03.01.754.0* PS momentum [GeV/c]261426142614 PS cycle length [s]3.61.23.61.23.61.2 SPS cycle length [s]21.66.021.66.021.66.0 SPS average current [ μ A]0.171.170.281.40.471.9 SPS power [kW]77470125565211747 *Feasibility including operational viability (especially in the PS) remains to be demonstrated

19. R. G. – 9/01/201419 ICFA EU Jan. 2014 - Paris LAGUNA-LBNO: HP-PS in the CERN accelerator complex LHC SPS PS PSB Experiments & Test Beams LINAC 4 LP - SPL CN2PY Target 2 MW HP-PS 2 Hz 1 Hz 160 MeV 4 GeV 50 / 75 GeV HP-PS repetition rate 1 Hz Inj. / Extr. Collimation Acceleration 3-fold Symmetry

20. R. G. – 9/01/201420 ICFA EU Jan. 2014 - Paris ParameterPS2 (ref.)HP-PS Circumference [m]1346.41174 Symmetry2-fold3-fold Beam Power [MW]0.372 Repetion Rate [Hz]0.421 Kinetic Energy @ ext. [GeV]5050/75 Protons/pulse [10 14 ]1.12.5/1.7 LAGUNA-LBNO: HP-PS main characteristics  3-fold symmetric ring with transfer, collimation and RF in separate long straight sections  Negative Momentum Compaction (NMC) arc cell to avoid transition  Doublet Long Straight Section (LSS) giving space for BT equipment, collimation and RF Based on PS2 design

21. R. G. – 9/01/201421 ICFA EU Jan. 2014 - Paris LAGUNA-LBNO: CN2PY layout  Layout for 400 GeV beam  Target cavern layout (shielding) for 50/75 GeV - 2MW beam  Same secondary beam elements for both beams:  Sufficient shielding against radiation (including muons, water and soil activation)  Target and focusing elements (horns) with similar parameters  Same beam decay volume, dump and near detector:  Deposited energy in target, shielding and dump will be 3 times higher for 2MW beam

22. R. G. – 9/01/201422 ICFA EU Jan. 2014 - Paris Option 1Option 2 Energy (GeV)2.5 or 52.5 and 5 Beam power (MW) 2.25 MW (2.5 GeV) or 4.5 MW (5 GeV) 5 MW (2.5 GeV) and 4 MW (5 GeV) Protons/pulse (x 10 14 )1.12 (2.5 GeV) + 1 (5 GeV) Av. Pulse current (mA)2040 Pulse duration (ms)0.91 (2.5 GeV) + 0.4 (5 GeV) 2  beam current  2  nb. of klystrons etc. Ion speciesH − Output Energy5GeV Bunch Frequency352.2MHz Repetition Rate50 Hz High speed chopper< 2 ns (rise & fall times) Required for muon production Required for flexibility and low loss in accumulator Required for low loss in accumulator HP-SPL: main characteristics

23. R. G. – 9/01/201423 ICFA EU Jan. 2014 - Paris Medium  cryomodule High  cryomodules Ejection 16 x 3  =0.65 cavities 12 x 8  =1 cavities 13 x 8  =1 cavities to EURISOL Debunchers To HP-PS and/or Accumulator High  cryomodules From Linac4 0 m0.16 GeV104 m0.66 GeV292 m2.5 GeV504 m5 GeV Segmented cryogenics / separate cryo-line / room temperature quadrupoles: -Medium  (0.65) – 3 cavities / cryomodule -High  (1) – 8 cavities / cryomodule Low energy Intermediate energy High energy HP-SPL: block diagram

24. R. G. – 9/01/201424 ICFA EU Jan. 2014 - Paris Accumulation of beam from the High Power SPL in a fixed energy Accumulator (5 GeV, 4MW beam power). Bunch compression («rotation») in a separate Compressor ring HP-SPL based NF proton driver

25. R. G. – 9/01/201425 ICFA EU Jan. 2014 - Paris Design and development of a new type of multi-cavity cryomodule, Design and development of “cheap” high power couplers (8 built; 2 successfully tested today). Extensive investment for superconducting cavities fabrication and test (e-beam welding machine, ep bench, optical bench…) 2 five-cell copper cavities, one bulk-niobium monocell produced, 4 five-cell bulk Niobium manufactured by industry (RI), One five-cell bulk Niobium in fabrication at CERN with an R&D approach, Equipment for testing at high RF power (704 MHz) a string of 4 cavities cooled at 2 K in SM18 Characterization of the potential of high power IOTs (in collaboration with ESS) before the end of 2016. A string of four SPL 704 MHz  =1 cavities will start being tested in a short cryo-module at the end of 2015. HP-SPL: R&D objectives

26. R. G. – 9/01/201426 ICFA EU Jan. 2014 - Paris Cavity Helium tank Inter-cavity support Thermal shield Vacuum vessel RF coupler Thermal shield tie-rod Cold-to-warm transition Magnetic shielding Insulation vacuum relief plate Cryogenic circuit burst disk Gate valve Two-phase pipe Cavity tuner Double-walled tube He phase separator Cryogenic lines port HP-SPL: Cryomodule Assembly of supporting system mock- up Inner part of supporting system mock- up

27. R. G. – 9/01/201427 ICFA EU Jan. 2014 - Paris HP-SPL: Niobium cavities 4 CAVITIES FABRICATED BY R.I. 4 CAVITIES FABRICATED BY R.I. CAVITY FABRICATION AT CERN Half-cells and beam tubes fabricated by spinning. RF measurements. e-beam welding machine for sc cavities

28. R. G. – 9/01/201428 ICFA EU Jan. 2014 - Paris CEA test bench with two SPL cylindrical window couplers, Double Walled Tubes and Test Box cavity Test of RF couplers (CEA) HP-SPL: High power RF couplers Cylindrical window Disk window Development of two types of couplers

29. R. G. – 9/01/201429 ICFA EU Jan. 2014 - Paris HP-SPL: HP-IOT development (Collaboration with ESS) High potential of cost savings wrt klystrons

30. RAL CERN ESS Plans for Proton Drivers at:

31. R. G. – 9/01/201431 ICFA EU Jan. 2014 - Paris ESS facility under construction (~1.5 B€ facility)

32. R. G. – 9/01/201432 ICFA EU Jan. 2014 - Paris ESS proton linac “Typical” superconducting proton linac 2 GeV beam energy (possibly upgradeable to 3.0 GeV) 5 MW average beam power 125 MW peak power 14 Hz repetition rate (2.86 ms pulse duration, 10 15 protons/pulse) 4% duty factor >2x10 23 p.o.t/year

33. R. G. – 9/01/201433 ICFA EU Jan. 2014 - Paris ESS construction schedule

34. R. G. – 9/01/201434 ICFA EU Jan. 2014 - Paris ESS evolution into a source Linac repetition rate doubled to 28 Hz [alternate production of neutrons and neutrinos (2.5 GeV H +  ~300 MeV )] New (additional) low energy front-end with H - ion source Accumulator(s) (ø 143 m) for pulse compression Target station (following study in EUROnu) Potential synergy with a fraction of the neutron users community interested in short pulses. (http://lanl.arxiv.org/abs/1212.5048)http://lanl.arxiv.org/abs/1212.5048 accumulator target/horn station

35. R. G. – 9/01/201435 ICFA EU Jan. 2014 - Paris ESS production target Split Proton Beam Neutrino Beam Direction Collimators Horns and Targets Decay Volume (He, 25 m) Beam Dump Horn Support Module Shield Blocks as studied in EUROnu for the CERN SPL

36. Summary Technological developments remain necessary for multi-GeV MW-class proton drivers of neutrino facilities to optimize design and minimize cost. Beam loss control/radio-protection issues are challenging. Three European laboratories could host a MW-class proton driver for a neutrino facility «piggybacked» on existing machines or planned projects: – RAL, simultaneously with an extension of ISIS delivering 5 MW at 5-10 GeV, – CERN, together with the renovation/replacement of some existing accelerators delivering 700 kW at 400 GeV, or 2 MW at 50-75 GeV or 5 MW at 5 GeV, – ESS, as a beam power upgrade delivering 5 MW at 2-3 GeV. Collaboration is worth enhancing world-wide, including all related HPPA projects (Accelerator Driven Systems, Neutron Spallation Sources, Radioactive Ion Sources): – Interest in common technologies (H - ion source, RFQ, High Power RF, SRF, charge exchange injection system, target,…), – Scarce level of resources

38. Spares

39. R. G. – 9/01/201439 ICFA EU Jan. 2014 - Paris 2014 2015 Preparation of components Assembly of CM HP-SPL: R&D Master Schedule

40. R. G. – 9/01/201440 ICFA EU Jan. 2014 - Paris Design goal for prototype IOT

41. R. G. – 9/01/201441 ICFA EU Jan. 2014 - Paris Tentative layout of neutrino factory at CERN