1. 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

2. 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 BI)
M.M.

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

4. CERN ACCELERATOR COMPLEX
from R. Garoby
EPAC’08
June , 2008
R.G.

5. 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 , 2008
R.G.

6. 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 , 2008
R.G.

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

8. PLANS FOR FUTURE INJECTORS: LINAC4
H- source
RFQ
chopper
DTL
CCDTL
PIMS
3 MeV
50 MeV
102 MeV
Bunch frequency 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.

9. 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.

10. 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 , 2008
R.G. 10

11. 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) (5 GeV)
Av. Pulse current
20 mA
40 mA
Pulse duration
1.2 ms
0.8 ms (2.5 GeV) ms (5 GeV)
EURISOL
Proton driver
HP-SPL beam characteristics
from R. Garoby
BENE’08
2-3 December 2008
R.G. 11

12. 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 , 2008
R.G.

13. 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.

14. 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.

15. 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.

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

17. 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
* s
Total duration of the burst
~50 s 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.

18. 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.

19. 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.

20. 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.

21. 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.

22. 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.