R. Garoby August 27, 2006

Introduction 5 GeV version of the SPL Scenarios for accumulation and compression Conclusion

SPL-BASED5 GeV PROTON DRIVER

R.G. 2 27/08/2006

Introduction (1/5)

Today’s characteristics and design of the SPL have been summarised in a recent publication [CERN-2006-006 available on the CERN Document Server]

Conceptual design of the SPL II : A high-power superconducting H- linac at CERN

Baylac, 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;

2006 Geneva : CERN, . - 104 p

R.G. 3 27/08/2006

Introduction (2/5)

Ion species H-

Kinetic energy 3.5 GeV

Mean current during the pulse 40 mA

Mean beam power 4 MW

Pulse repetition rate 50 Hz

Pulse duration 0.57 ms

Bunch frequency 352.2 MHz

Duty cycle during the pulse 62 (5/8) %

rms transverse emittances 0.4 mm mrad

Longitudinal rms emittance 0.3 deg MeV

Length 430 m

SPL (CDR2) main characteristics

R.G. 4 27/08/2006

Introduction (3/5)

Section Tout

[MeV]

Nb. of cavities

PRF peak [MW]

Nb. of klystrons

Length [m]

Source 0.095 - - - 3

RFQ 3 1 1 1 6

Chopper (MEBT) 3 3 0.1 - 3.7

DTL 40 3 3.8 5 13.6

CCDTL 90 24 6.4 8 25.5

SCL 180 24 15.1 5 34.9

Superconducting =0.65 643 42 18.5 7 86

Superconducting =1.0 3560 136 116.7 32 256

Total 3560 233 161.6 58 429

SPL (CDR2) accelerating sections

R.G. 5 27/08/2006

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.

PS ring

Booster

TT2 line

Bldg 152

Bldg 150

Linac 2

Linac 3

Linac 4

PS ring

Booster

TT2 line

Bldg 152

Bldg 150

Linac 2

Linac 3

Linac 4

R.G. 6 27/08/2006

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.

PSB SPL’RCPSB

SPSSPS+

Linac4

SPL

PS

LHC / SLHC DLHC

Out

put

ener

gy

160 MeV

1.4 GeV~ 5 GeV

26 GeV40 – 60 GeV

450 GeV1 TeV

7 TeV~ 14 TeV

Linac250 MeV

SPL: Superconducting Proton Linac (~ 5 GeV)

SPL’: RCPSB injector(0.16 to 0.4-1 GeV)

RCPSB: Rapid Cycling PSB(0.4-1 to ~ 5 GeV)

PS2: High Energy PS(~ 5 to 50 GeV – 0.3 Hz)

PS2+: Superconducting 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)

Proton flux / Beam power

PS2 (PS2+)

PSB SPL’RCPSB

SPSSPS+

Linac4

SPL

PS

LHC / SLHC DLHC

Out

put

ener

gy

160 MeV

1.4 GeV~ 5 GeV

26 GeV40 – 60 GeV

450 GeV1 TeV

7 TeV~ 14 TeV

Linac250 MeV

SPL: Superconducting Proton Linac (~ 5 GeV)

SPL’: RCPSB injector(0.16 to 0.4-1 GeV)

RCPSB: Rapid Cycling PSB(0.4-1 to ~ 5 GeV)

PS2: High Energy PS(~ 5 to 50 GeV – 0.3 Hz)

PS2+: Superconducting 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)

Proton flux / Beam power

PS2 (PS2+)

R.G. 7 27/08/2006

5 GeV version of the SPL

SPL (CDR3) characteristics

Ion species H-

Kinetic energy 5 GeV

Mean current during the pulse 40 mA

Mean beam power 4 MW

Pulse repetition rate 50 Hz

Pulse duration 0.4 ms

Bunch frequency 352.2 MHz

Duty cycle during the pulse 62 (5/8) %

rms transverse emittances 0.4 mm mrad

Longitudinal rms emittance 0.3 deg MeV

Length 535 m

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].

R.G. 8 27/08/2006

Scenario for accumulation and compression (1/13)

Parameter Basic value Range

Beam energy [GeV] 10 5 - 15

Burst repetition rate [Hz] 50 ?

Number of bunches per burst (n) 4 1 – 6 ?

Total duration of the burst [ns] ~ 50 40 - 60

Time interval between bunches [s] (tint) 16 0.6 – 16 ?

Bunch length [ns] 2 1 - 3

Specifications (from R. Palmer’s conclusion at ISS meeting in RAL on Thursday 27, April 2006)

~ 50/(n-1)

R.G. 9 27/08/2006

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]

R.G. 10 27/08/2006

Scenario for accumulation and compression (3/13)

Mean radius [m] (LA = 74/73 LC) 50.685

< 0.02

2T ~ 49

fREV [MHz] 0.929553

VRF [V] 0

Number of bunches 6

Bunch length / gap between bunches [ns] 120 / 59

Number of protons per bunches 1.7 1013

Accumulator

Mean radius [m] (LC = 73/74 LA) 50

2T 5.29

fREV [MHz] 0.942288

hRF 3

fRF [MHz] 2.826864

VRF [MV] 4

Number of protons per bunches 1.7 1013

Compressor

R.G. 11 27/08/2006

Scenario for accumulation and compression (4/13)

Kinetic energy [GeV] 5

ETotal [MeV] 10

lbunch total [ns] at injection 120

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 1.7 1013

Bunch characteristics at injection in

the compressor

Kinetic energy [GeV] 5

ETotal [MeV] ~ 170 MeV

bunch [ns] at ejection ~ 2 ns

Time interval between ejection [s] ~ 12

Number of bunches 6

Duration of full burst to the target [s] ~ 60

Number of protons per bunches 1.7 1013

Bunch characteristics at ejection to

the target

R.G. 12 27/08/2006

Scenario for accumulation and compression (5/13)

PDAC

2.2 GeV

PDAC

5 GeV

Improvement factor

2 10.675 39.552 3.705

Total number of protons per pulse 1.136 1016 0.5 1016 2.273

Ring circumference [m] 2 150 2 50 3

Number of bunches 144 6 1/24

Product 1.05 !

Scaling for space charge induced Q with respect to PDAC (2.2 GeV)

1

2

221

2

1

2

1

2

C

C

N

N

h

h

Number of bunches

Number of protons

Beam energy

Ring circumference

R.G. 13 27/08/2006

Scenario for accumulation and compression (6/13)

Longitudinal phase space at injection in the

compressor

Space charge voltage

Simulations: C. Carli

R.G. 14 27/08/2006

Scenario for accumulation and compression (7/13)

Longitudinal phase space after 25 s in

the compressor

Space charge voltage

Simulations: C. Carli

R.G. 15 27/08/2006

Scenario for accumulation and compression (8/13)

Longitudinal phase space after 38 s in

the compressor

Space charge voltage

Simulations: C. Carli

R.G. 16 27/08/2006

Scenario for accumulation and compression (9/13)

Longitudinal phase space after 38 s in

the compressor

Line density

= 1.9 ns

Simulations: C. Carli

R.G. 17 27/08/2006

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

R.G. 18 27/08/2006

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]

R.G. 19 27/08/2006

Alternative scenario for 5 bunches (12/13)

Mean radius [m] (LA = 185/183 LC) 50.546448

< 0.02

2T ~ 49

fREV [MHz] 0.932095

VRF [V] 0

Number of bunches 5

Bunch length / gap between bunches [ns] 120/95

Number of protons per bunches 2 1013

Accumulator

Mean radius [m] (LC = 183/185 LA) 50

2T 5.29

fREV [MHz] 0.942288

hRF 3

fRF [MHz] 2.826864

VRF [MV] 4

Number of protons per bunches 2 1013

Compressor

R.G. 20 27/08/2006

Kinetic energy [GeV] 5

ETotal [MeV] 10

lbunch total [ns] at injection 120

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 2 1013

Bunch characteristics at injection in

the compressor

Kinetic energy [GeV] 5

ETotal [MeV] ~ 170 MeV

bunch [ns] at ejection ~ 2 ns

Time interval between ejection [s] ~ 12

Number of bunches 5

Duration of full burst to the target [s] ~ 50

Number of protons per bunches 2 1013

Bunch characteristics at ejection to

the target

Alternative scenario for 5 bunches (13/13)

R.G. 21 27/08/2006

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.

R.G. 22 27/08/2006