August 27, 2006R. Garoby Introduction 5 GeV version of the SPL Scenarios for accumulation and compression Conclusion SPL-BASED 5 GeV PROTON DRIVER
27/08/2006R.G.2 Introduction (1/5) Today’s characteristics and design of the SPL have been summarised in a recent publication [CERN available on the CERN Document Server] Conceptual design of the SPL II : A high-power superconducting H - linac at CERN Baylac, MBaylac, M; (LPSC Grenoble) Gerigk, F (ed.); Benedico Mora, E; Caspers, F; Chel, S (CEA Saclay) ; Deconto, J M (LPSC Grenoble) ; Duperrier, R (CEA Saclay) ; Froidefond, E (LPSC Grenoble) ; Garoby, R; Hanke, K; Hill, C; Hori, M (CERN and Tokyo Univ.) ; Inigo-Golfin, J; Kahle, K; Kroyer, T; Küchler, D; Lallement, J B; Lindroos, M; Lombardi, A M; López Hernández, A; Magistris, M; Meinschad, T K; Millich, Antonio; Noah Messomo, E; Pagani, C (INFN Milan) ; Palladino, V (INFN Maples) ; Paoluzzi, M; Pasini, M; Pierini, P (INFN Milan) ; Rossi, C; Royer, J P; Sanmartí, M; Sargsyan, E; Scrivens, R; Silari, M; Steiner, T; Tückmantel, Joachim; Uriot, D (CEA Saclay) ; Vretenar, M;Gerigk, FBenedico Mora, ECaspers, FChel, SDeconto, J MDuperrier, R Froidefond, EGaroby, RHanke, KHill, CHori, MInigo-Golfin, JKahle, KKroyer, TKüchler, DLallement, J B Lindroos, MLombardi, A MLópez Hernández, AMagistris, MMeinschad, T K Millich, AntonioNoah Messomo, EPagani, CPalladino, VPaoluzzi, MPasini, MPierini, PRossi, CRoyer, J P Sanmartí, MSargsyan, EScrivens, RSilari, MSteiner, TTückmantel, Joachim Uriot, DVretenar, M 2006 Geneva : CERN, p
27/08/2006R.G.3 Introduction (2/5) Ion speciesH-H- Kinetic energy3.5GeV Mean current during the pulse40mA Mean beam power4MW Pulse repetition rate50Hz Pulse duration0.57ms Bunch frequency352.2MHz Duty cycle during the pulse62 (5/8)% rms transverse emittances0.4 mm mrad Longitudinal rms emittance0.3 deg MeV Length430m SPL (CDR2) main characteristics
27/08/2006R.G.4 Introduction (3/5) SectionT out [MeV] Nb. of cavities P RF peak [MW] Nb. of klystrons Length [m] Source RFQ31116 Chopper (MEBT) DTL CCDTL SCL Superconducting = Superconducting = Total SPL (CDR2) accelerating sections
27/08/2006R.G.5 Introduction (4/5) The low energy part (up to 160 MeV) of the SPL is the subject of the “Linac4” project. A decision is expected by the end of the year.
27/08/2006R.G.6 Introduction (5/5) The SPL is part of a global strategy outlined by the PAF working group for the upgrade of the proton accelerator complex at CERN.
27/08/2006R.G.7 5 GeV version of the SPL SPL (CDR3) characteristics Ion speciesH-H- Kinetic energy5GeV Mean current during the pulse40mA Mean beam power4MW Pulse repetition rate50Hz Pulse duration0.4ms Bunch frequency352.2MHz Duty cycle during the pulse62 (5/8)% rms transverse emittances0.4 mm mrad Longitudinal rms emittance0.3 deg MeV Length535m Increasing the energy of the SPL (CDR2) is obtained by adding 105 m of =1 superconducting accelerating structures and 14 klystrons [704 MHz – 5 MW].
27/08/2006R.G.8 Scenario for accumulation and compression (1/13) ParameterBasic valueRange Beam energy [GeV] Burst repetition rate [Hz]50? Number of bunches per burst (n)41 – 6 ? Total duration of the burst [ns]~ Time interval between bunches [ s] (t int ) – 16 ? Bunch length [ns] Specifications (from R. Palmer’s conclusion at ISS meeting in RAL on Thursday 27, April 2006) ~ 50/(n-1)
27/08/2006R.G.9 Scenario for accumulation and compression (2/13) Accumulation Duration = 400 s Compression t = 0 s t = 12 s t = 24 s t = 36 s etc. until t = 96 s Accumulator [120 ns pulses - 60 ns gaps] SPL beam [42 bunches - 21 gaps] Compressor [120 ns bunch - V(h=3) = 4 MV] Target [2 ns bunches – 6 times]
27/08/2006R.G.10 Scenario for accumulation and compression (3/13) Mean radius [m] (L A = 74/73 L C ) < 0.02 2T2T ~ 49 f REV [MHz] V RF [V]0 Number of bunches6 Bunch length / gap between bunches [ns]120 / 59 Number of protons per bunches Accumulator Mean radius [m] (L C = 73/74 L A )50 2T2T 5.29 f REV [MHz] h RF 3 f RF [MHz] V RF [MV]4 Number of protons per bunches Compressor
27/08/2006R.G.11 Scenario for accumulation and compression (4/13) Kinetic energy [GeV]5 E Total [MeV] 10 l bunch total [ns] at injection120 Time interval between centres of consecutive bunches [ns] ~ 354 Time interval between transfers [ s] ~ 12 Duration of bunch rotation for 1 bunch [ s] ~ 3 x 12 Number of protons per bunches Bunch characteristics at injection in the compressor Kinetic energy [GeV]5 E Total [MeV] ~ 170 MeV bunch [ns] at ejection ~ 2 ns Time interval between ejection [ s] ~ 12 Number of bunches6 Duration of full burst to the target [ s] ~ 60 Number of protons per bunches Bunch characteristics at ejection to the target
27/08/2006R.G.12 Scenario for accumulation and compression (5/13) PDAC 2.2 GeV PDAC 5 GeV Improvement factor Total number of protons per pulse Ring circumference [m] 2 1502 50 3 Number of bunches14461/24 Product1.05 ! Scaling for space charge induced Q with respect to PDAC (2.2 GeV) Number of bunches Number of protons Beam energy Ring circumference
27/08/2006R.G.13 Scenario for accumulation and compression (6/13) Longitudinal phase space at injection in the compressor Space charge voltage Simulations: C. Carli
27/08/2006R.G.14 Scenario for accumulation and compression (7/13) Longitudinal phase space after 25 s in the compressor Space charge voltage Simulations: C. Carli
27/08/2006R.G.15 Scenario for accumulation and compression (8/13) Longitudinal phase space after 38 s in the compressor Space charge voltage Simulations: C. Carli
27/08/2006R.G.16 Scenario for accumulation and compression (9/13) Longitudinal phase space after 38 s in the compressor Line density = 1.9 ns Simulations: C. Carli
27/08/2006R.G.17 Scenario for accumulation and compression (10/13) Longitudinal phase space after 38 s in the compressor Line density = 1.5 ns Tentative use of 2nd harmonic RF (700 kV) Simulations: C. Carli
27/08/2006R.G.18 Alternative scenario for 5 bunches (11/13) Accumulation Duration = 400 s Compression t = 0 s t = 12 s t = 24 s t = 36 s etc. until t = 84 s Accumulator [120 ns pulses - 95 ns gaps] SPL beam [42 bunches - 33 gaps] Compressor [120 ns bunch - V(h=3) = 4 MV] Target [2 ns bunches – 5 times]
27/08/2006R.G.19 Alternative scenario for 5 bunches (12/13) Mean radius [m] (L A = 185/183 L C ) < 0.02 2T2T ~ 49 f REV [MHz] V RF [V]0 Number of bunches5 Bunch length / gap between bunches [ns]120/95 Number of protons per bunches Accumulator Mean radius [m] (L C = 183/185 L A )50 2T2T 5.29 f REV [MHz] h RF 3 f RF [MHz] V RF [MV]4 Number of protons per bunches Compressor
27/08/2006R.G.20 Kinetic energy [GeV]5 E Total [MeV] 10 l bunch total [ns] at injection120 Time interval between centres of consecutive bunches [ns] ~ 354 Time interval between transfers [ s] ~ 12 Duration of bunch rotation for 1 bunch [ s] ~ 3 x 12 Number of protons per bunches Bunch characteristics at injection in the compressor Kinetic energy [GeV]5 E Total [MeV] ~ 170 MeV bunch [ns] at ejection ~ 2 ns Time interval between ejection [ s] ~ 12 Number of bunches5 Duration of full burst to the target [ s] ~ 50 Number of protons per bunches Bunch characteristics at ejection to the target Alternative scenario for 5 bunches (13/13)
27/08/2006R.G.21 Conclusion Although very preliminary, this analysis gives hope that a scenario can be set-up for meeting the ISS specifications with an SPL based 5 GeV proton driver. A refined analysis is needed that will take into account collective effects. Absolute comparison with other proton drivers will have to take into account: Pion production and muon capture using the HARP results. The SPL energy could be marginally increased if necessary. Change of muon capture efficiency with bunch length. Construction and operation cost. Technological risk. Relative (“site specific”) comparison will have to include: Interest for other uses, flexibility, upgrade potential. Match with local competences, industrial interest, real-estate availability. Synergy with other work programmes.
27/08/2006R.G.22