Progress towards Pulsed Multi-MW CERN Proton Drivers Status & Plans at CERN PLANS FOR FUTURE INJECTORS n FACTORY: SPL-BASED PROTON DRIVER Summary R. Garoby M. Martini

Special contributions to the neutrino factory studies: Credits Roland Garoby Presentation at NuFact 06, August 24-30, 2006 Presentation at EPAC 08, June 23-27, 2008 Presentation at BENE 08, December 2-3, 2008 Special contributions to the neutrino factory studies: Masamitsu Aiba (CERN-AB-2008-060 BI) M.M.

Status and Plans at CERN R.G. BENE’08 2-3 December 2008

CERN ACCELERATOR COMPLEX from R. Garoby EPAC’08 June 23 -27, 2008 R.G.

Main performance limitation PLANS FOR FUTURE INJECTORS: Motivation Lack of reliability Ageing accelerators (PS is 48 years old) operating far beyond initial parameters Þ Need to increase the injection energy in the synchrotrons Main performance limitation Incoherent space charge tune spreads DQSC at injection in the PSB (50 MeV) and PS (1.4 GeV) due to the required beam brightness N/e* Increase injection energy in the PSB from 50 to 160 MeV kinetic Increase injection energy in the SPS from 25 to 50 GeV kinetic Design the PS successor (PS2) with a tolerable space charge effect for the maximum beam envisaged for SLHC => injection energy of 4 GeV from R. Garoby EPAC’08 June 23 -27, 2008 R.G.

PLANS FOR FUTURE INJECTORS: Description Proton flux / Beam power Linac2 Linac4 50 MeV from R. Garoby 160 MeV PSB (LP)SPL 1.4 GeV (LP)SPL: (Low Power) Superconducting Proton Linac (4-5 GeV) PS2: High Energy PS (~ 5 to 50 GeV – 0.3 Hz) SPS+: Superconducting SPS (50 to1000 GeV) SLHC: “Superluminosity” LHC (up to 1035 cm-2s-1) DLHC: “Double energy” LHC (1 to ~14 TeV) 4 GeV PS 26 GeV PS2 50 GeV Output energy SPS 450 GeV SPS+ 1 TeV LHC / SLHC DLHC 7 TeV ~ 14 TeV EPAC’08 June 23 -27, 2008 R.G.

PLANS FOR FUTURE INJECTORS: Layout SPS PS2 ISOLDE PS SPL from R. Garoby Linac4 EPAC’08 June 23 -27, 2008 R.G.

PLANS FOR FUTURE INJECTORS: LINAC4 H- source RFQ chopper DTL CCDTL PIMS 3 MeV 50 MeV 102 MeV Bunch frequency 352.2 MHz 160 MeV Layout Length: 80 m Ion species H- Output kinetic energy 160 MeV Bunch frequency 352.2 MHz Max. repetition rate 1.1 (2) Hz Beam pulse duration 0.4 (1.2) ms Chopping factor (beam on) 62% Source current 80 mA RFQ output current 70 mA Linac current 64 mA Average current during beam pulse 40 mA Beam power 5.1 kW Particles / pulse 1014 Beam characteristics from R. Garoby BENE’08 2-3 December 2008 R.G.

PLANS FOR FUTURE INJECTORS: LP-SPL Linac4 (160 MeV) SC-linac (4 GeV) H- source RFQ chopper DTL CCDTL PIMS 3 MeV 50 MeV 102 MeV 352.2 MHz β=0.65 β=0.92 643 MeV 4 GeV 704.4 MHz 180 MeV Length: 460 m Kinetic energy (GeV) 4 Beam power at 4 GeV (MW) 0.16 Rep. period (s) 0.6 Protons/pulse (x 1014) 1.5 Average pulse current (mA) 20 Pulse duration (ms) 1.2 LP-SPL beam characteristics from R. Garoby BENE’08 2-3 December 2008 R.G.

PLANS FOR FUTURE INJECTORS: PS2 from R. Garoby PS2 main characteristics compared to the present PS PS2 PS Injection energy kinetic (GeV) 4.0 1.4 Extraction energy kinetic (GeV) ~50 13 / 25 Circumference (m) 1346 628 Maximum intensity LHC (25ns) (p/b) 4.01011 ~1.71011 Maximum intensity for fixed target physics (p/p) 1.21014 3.31013 Maximum energy per beam pulse (kJ) 1000 70 Max ramp rate (T/s) 1.5 2.2 Cycle time at 50 GeV (s) 2.4 1.2 / 2.4 Max. effective beam power (kW) 400 60 PS2 & present PS beam characteristics EPAC’08 June 23 -27, 2008 R.G. 10

PLANS FOR FUTURE INJECTORS: HP-SPL Linac4 (160 MeV) SC-linac (5 GeV) H- source RFQ chopper DTL CCDTL PIMS 3 MeV 50 MeV 102 MeV 352.2 MHz β=0.65 β=1.0 643 MeV 5 GeV 704.4 MHz 180 MeV Length: 540 m Option 1 Option 2 Energy 2.5 or 5 GeV 2.5 and 5 GeV Beam power 3 MW (2.5 GeV) or 6 MW (5 GeV) 4 MW (2.5 GeV) and 4 MW (5 GeV) Rep. frequency 50 Hz Protons/pulse 1.51014 2 1014 (2.5 GeV) + 1014 (5 GeV) Av. Pulse current 20 mA 40 mA Pulse duration 1.2 ms 0.8 ms (2.5 GeV) + 0.4 ms (5 GeV) EURISOL Proton driver HP-SPL beam characteristics from R. Garoby BENE’08 2-3 December 2008 R.G. 11

PLANS FOR FUTURE INJECTORS: Benefits Linac4 (higher performance for the PSB) Space charge decreased by a factor of 2 in the PSB Þ potential to double the beam brightness and fill the PS with the LHC beam in a single pulse / potential for ultimate beam from the PS Þ easier handling of high intensity Low loss injection process for reliably reaching high beam brightness (charge exchange injection instead of betatron stacking) Flexibility for transverse and longitudinal beam painting More intensity per pulse available for PSB beam users (ISOLDE) – up to 2 More PSB cycles available for other uses than LHC LP-SPL & PS2 (higher performance) Capability to deliver 2.2 the ultimate beam for LHC to the SPS Þ potential to prepare the SPS for supplying the beam required for the SLHC Higher injection energy in the SPS + higher intensity and brightness Þ easier handling of high intensity (potential to boost the intensity per pulse) / potential to improve SPS operation in fixed target mode 50% of the LP-SPL pulses will be available (not needed by PS2) Þ new nuclear physics experiments – extension of ISOLDE (if no EURISOL) HP-SPL (for new experimental facilities using very high beam power) Proton driver for a neutrino factory (4 MW at 5 GeV) Radioactive ion beam facility (ISOL-like) (4 MW at 2.5 GeV for EURISOL) from R. Garoby 2400 batches =6 batches x 400 turn EPAC’08 June 23 -27, 2008 R.G.

PLANS FOR FUTURE INJECTORS: Planning LINAC4 Milestones End civil engineering work December 2010 Installation 2011 Linac commissioning 2012 Modification PSB Shutdown 2012/13 (6 months) Beam from PSB May 2013 from R. Garoby LP-SPL and PS2 Milestones Project proposal June 2011 Project start January 2012 LP-SPL commissioning Mid-2015 PS2 commissioning Mid-2016 SPS commissioning May 2017 Beam for physics July 2017 HP-SPL Milestones Staged hardware upgrade during shutdowns Earliest year of operation 2020 Building (resp. commissioning) of LP-SPL & PS2 will not interfere with the regular operation of Linac4+PSB for physics (resp. with physics) The upgrade from LP-SPL to HP-SPL will depend upon the approval of major new physics programmes for Radioactive Ion beams (EURISOL-facility) and/or for neutrinos (Neutrino Factory) BENE’08, 2-3 December 2008 R.G.

PLANS FOR FUTURE INJECTORS: HP-SPL layout EURISOL-type facility from R. Garoby EURISOL EXPERIMENTAL HALLS TARGETS RADIOACTIVE IONS LINAC ISOLDE OR EURISOL HIGH ENERGY EXPERIMENTAL HALL TRANSFER LINE SPL to ISOLDE TRANSFER LINES SPL to EURISOL BENE’08 2-3 December 2008 R.G.

PLANS FOR FUTURE INJECTORS: HP-SPL layout Neutrino Factory (earlier possible layout ) MUON ACCELERATORS MUON PRODUCTION TARGET MUON STORAGE RING ACCUMULATOR& COMPRESSOR SPL from R. Garoby BENE’08 2-3 December 2008 R.G.

Earlier possible layout of a CERN Neutrino Factory CERN-2004-002; ECFA-04-230 (2004) Recirculating linacs 2  50 GeV M.M.

n FACTORY: SPL-based proton driver (1/5) from M. Aiba SPL based 5 GeV - 4 MW proton driver design: HP-SPL + 2 fixed energy rings (accumulator & compressor) Feasibility Study of Accumulator and Compressor for the 6-bunches SPL based Proton Driver Time structure of the primary proton beam Parameters Basic values Range Kinetic energy 10 GeV 5-15 GeV Burst repetition rate 50 Hz ? Number of bunches per burst 4 1 - 6 Time interval between bunches 16* s 0.6 - 16* s Total duration of the burst ~50 s 40 - 60 s Bunch length 2 ns 1 - 3 ns Specifications (from R. Palmer’s conclusion at ISS meeting in RAL on Thursday 27, April 2006) * Maximum bunch spacing ~50/(Nb-1) for the number of bunches Nb >2 BENE’08 2-3 December 2008 R.G.

n FACTORY: SPL-based proton driver (2/5) from M. Aiba SPL beam: 5 GeV, 1014 H-/cycle at 50 Hz = 4 MW Accumulation for the 6-bunches SPL based proton driver (314.2 m accumulator) ... ~420 s 50 Hz = 20 ms 6 bunches in accumulator ~1.06 s ~40 mA average (~60 mA peak) 5 6 2 4 1 3 4 5 6 1 2 3 batch ~120 ns = 42 SPL bunches ~420 s Gap ~ 60 ns = 20 empty bunches 2400 batches =6 batches x 400 turn 1.671013 protons per bunch at end of accumulation (400 turns) M.M.

n FACTORY: SPL-based proton driver (3/5) from M. Aiba Accumulator (120 ns pulses - 60 ns gaps) SPL beam (42 bunches - 21 gaps) Accumulation Duration ~400 ms Compression t = 0 ms t = 12 ms t = 24 ms t = 36 ms etc. until t = 96 ms Compressor (120 ns bunch – V (h=3) = 4 MV) Target: 6 bunches of 2 ns 36 turns necessary for bunch compression Þ ~12 ms bunch spacing at ejection BENE’08, 2-3 December 2008 R.G.

n FACTORY: SPL-based proton driver (4/5) from M. Aiba Phase rotation to shorten the bunch length to 2 ns BENE’08 2-3 December 2008 R.G.

n FACTORY: SPL-based proton driver (5/5) Parameters Accumulator Compressor Circumference 318.5 m 314.2 m Number of turns for accumulation 400 - Number of turns for compression 36 Maximum nb of simultaneous bunches 6 3 Nb of protons per bunch 1.671013 RF voltage 0 MV 4 MV Harmonic number Gamma transition (t) 6.33 2.3 Slip factor (= t-2- --2) ~0* (isochronous) 0.16** * To freeze the bunches longitudinally during accumulation so that no RF cavities are needed ** Large slip factor to do the phase rotation rapidly to fulfill the total burst duration requirement Beam at injection in the compressor Beam at ejection to the target Parameters Values Kinetic beam energy 5 GeV Time interval between bunches ~354 ns Nb of bunches per cycle 6 Total bunch length 120 ns Bunch length (r.m.s.) 2 ns Time interval between transfer 12 s Time interval between ejection Duration of one bunch rotation 312 s Duration of the full burst to the target 60 s from M. Aiba from R. Garoby NUFACT’06, 24-3 August 2006 R.G.

Summary from R. Garoby There has been major progress towards future pulsed proton drivers at CERN: The upgrade of the LHC hadron injectors has been studied The first stage of implementation is approved and taking place before 2013 The preparation of detailed project proposals for the second stage (mid-2011) is also approved An SPL-based proton driver meeting the IDS specifications has been designed. It could be realized after the maximum SPL potential is obtained in a third stage (~2020) Many issues merit investigation to prepare for multi-MW proton drivers: Detailed design of the accelerators with prototyping of key components Charge exchange injection in the synchrotron (Laser stripping?) Stability and feasible emittances in the synchrotron Components activation, maintenance… Target and target area BENE’08 2-3 December 2008 R.G.