1. Plans for a Superconducting Proton Linac at CERN
Part 2
R. Garoby – 10/06/2010

2. OUTLINE Introduction (SC linac)
Low Power SPL in a new LHC injector complex
High power SPL as a proton driver
R & D plans

3. High Power SPL as a proton driver
* Detailed during Workshop on
“European Strategy for Future Neutrino Physics”
CERN, 1-3 October 2009

4. SC-linac [160 MeV ® 5 GeV] with ejection at intermediate energy
HP-SPL: Block diagram
Compared to the LP-SPL, it requires:
Upgrade of infrastructure (cooling water, electricity, cryogenics etc.)
Replacement of klystron power supplies,
Addition of 5 high b cryomodules to accelerate up to 5 GeV
SC-linac [160 MeV ® 5 GeV] with ejection at intermediate energy
0 m
0.16 GeV
110 m
0.73 GeV
291 m
2.5 GeV
500 m
5 GeV
High Power SPL as a proton driver
Medium b cryomodule
High b cryomodules
High b cryomodules
Debunchers
From Linac4
Ejection
To PS2 and Accumulator
9 x 6
b=0.65 cavities
11 x 8
b=1 cavities
13 x 8
b=1 cavities
EURISOL to
Length: ~500 m

5. HP-SPL: main characteristics & options
Beam characteristics of the main options
Option 1
Option 2
Energy (GeV)
2.5 or 5
2.5 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)
Rep. frequency (Hz) 50
Protons/pulse (x 1014)
1.1
2 (2.5 GeV) + 1 (5 GeV)
Av. Pulse current (mA) 20 40
Pulse duration (ms)
0.9
1 (2.5 GeV) (5 GeV)
Faster rep. rate Þ new power supplies, more cooling etc.
High Power SPL as a proton driver
2 ´ beam current Þ 2 ´ nb. of klystrons etc .

6. SPL-based proton driver: principle [1/8]
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 [ms]
~ 50
Time interval between bunches [ms] (tint) 16
~ 50/(n-1)
Bunch length [ns] 2
1 - 3
Specifications
(from ISS report)
SPL – based Proton Driver
SPL-based 5 GeV – 4 MW proton drivers have been designed [SPL + 2 fixed energy rings (accumulator & compressor)] which meet these requirements
References:
SPL based proton driver/ R. Garoby, talk at NuFact06,
Feasibility Study of Accumulator and Compressor for the 6-bunches SPL-based Proton Driver / M. Aiba, CERN-AB
A first analysis of 3-bunches and 1-bunch scenario for the SPL-based Proton Driver / M. Aiba, CERN-AB-Note BI
Beam Stability in the SPL Proton Driver Accumulator for a Neutrino Factory at CERN / E. Benedetto, to be published
SPL-based Proton Driver for a Neutrino Factory at CERN, M. Aiba, E. Benedetto, R. Garoby, M. Meddahi, poster nb.25 (this workshop)

7. SPL-based proton driver: principle [2/8]
Beam accumulation
Accumulator ring
Charge exchange injection
~nx100ms accumulation time
Isochronous (h=0): beam frozen longitudinally to preserve Dp/p
No RF (=> minimum impedance)
1-6 bunches of ~120 ns length
Bunch compression
Compressor ring
Large RF voltage (large stored energy & minimum RF power) (=> bunch rotation on stored energy)
Large slippage factor h => rapid phase rotation in few x10ms,
~2ns rms bunch extraction to the target (=> moderate DQ because of dispersion)
Synchronization between rings
- Ratio of circumferences guaranteeing correct positioning of successive bunches inside the compressor without energy change in any ring
SPL - based Proton Driver

8. SPL-based proton driver: principle - Generation of 6 bunches - [3/8]
Accumulator
SPL – based Proton Driver

9. SPL-based proton driver: principle - Generation of 6 bunches - [4/8]
Accumulator
[120 ns pulses -
60 ns gaps]
Accumulation
Duration = 400 ms
Compression
t = 0 ms
t = 12 ms
t = 24 ms
t = 36 ms
etc. until t = 96 ms
SPL beam
[42 bunches -
21 gaps]
Compressor
[120 ns bunch -
V(h=3) = 4 MV]
SPL – based Proton Driver
Target
[2 ns bunches – 6 times]

10. SPL-based proton driver: principle - Bunch rotation - [5/8]
from M. Aiba
SPL – based Proton Driver

11. SPL-based proton driver: principle - Ring parameters - [6/8]
from M. Aiba
SPL – based Proton Driver

12. SPL-based proton driver: principle - Alternatives with less bunches - [7/8]
from M. Aiba
SPL
Accumulator
SPL – based Proton Driver

13. SPL-based proton driver: principle - Alternatives with less bunches - [8/8]
from M. Aiba
Accumulator
[~100 ns pulses ~110 ns gaps]
Accumulation
Duration = 400 ms
Compression
t = 0 ms
t = 30 ms
t = 60 ms
etc. until
t = 120 ms
SPL beam
[35 ± 7 bunches,
38 ± 7 gaps]
Compressor
[120 ns bunch -
V(h=3) = 1.7 MV]
SPL – based Proton Driver
Target
[2 ns bunches – 3 times]

14. R & D plans

15. R & D for a high power SPL Motivation Description
Preserve potential for some alternative physics programmes (Neutrinos, RIB)
Preserve possibility of new injectors at long term (e.g. DLHC option…)
Update CERN competences in superconducting RF
Synergy with other applications outside of CERN
Description
Focused on high beam power
R & D only (no work on integration / civil engineering / environmental impact)
SPL R & D status and plans

16. Organization Study leader: R. Garoby SPL Collaboration
Coordinator
External partners
RF hardware (low level & high power)
E. Ciapala
Cockcroft Institute, ESS + (FNAL, SNS, JLAB, ANL)
Cavities (structures & auxiliary equipment)
W. Weingarten
CEA-Saclay, CNRS-Orsay, TRIUMF, Stony Brook + (JLAB, SNS)
Cryomodule (cryostat & cryogenics)
V. Parma
CEA-Saclay, CNRS-Orsay, Stony Brook + (FNAL)
Beam dynamics (beam parameters)
A. Lombardi
CEA-Saclay, TRIUMF, Soltan Institute, ESS
Architecture (layout & geometry, extraction, transfer)
F. Gerigk
Surface treatment and vacuum
S. Calatroni
Mechanical design and construction
O. Capatina
Working Groups
SPL R & D status and plans
Structured storage for all SPL documentation in EDMS
Structured filing of all SPL meetings and workshops in Indico
Structured filing of all collaboration meetings in Indico

17. Progress (from LP-SPL work)
Choice of the main parameters of the SPL sc cavities (frequency, operating temperature and gradient)
Choice of b=1 for the high energy cavities (F. Gerigk et al., “Choice of the optimum beta for the SPL SC cavities”)
Debate & conclusion on HOMs damping needs [outcome of workshop on June at CERN]
Decision to pass one waveguide per cavity from technical gallery to accelerator tunnel
Refinement of SPL beam parameters
Updated accelerator layout with intermediate energy ejections
Progress in the analysis of high power RF
Start of work on SPL high power RF coupler
Start of coordination of sc cavities development
SPL R & D status and plans

18. Main meetings Six technical workshops:
March 2010: Review of SPL RF couplers
January 2010: RF needs for SPL sc cavities tests
November 2009: Workshop on cryogenic and vacuum sectorisations of the SPL  
September 2009: Mechanical issues SPL cavities/cryomodules  
June 2009: SPL HOM workshop  
April 2008: Status of analysis of SPL RF frequency and cooling temperature
Three [4] Collaboration Meetings:
[June 2010: 4th SPL Collaboration Meeting (Lund)]
November 2009: 3rd SPL Collaboration Meeting (CERN)
May 2009: 2nd SPL Collaboration Meeting (Vancouver)
December 2008: 1st SPL Collaboration meeting (CERN)
SPL R & D status and plans

19. R & D subjects until 2015
Partly addressed in sLHC-PP
(in continuity with the work previously done for the LP-SPL)
R & D towards a high duty cycle H- source (continued after end of SLHC-PP)
Study of the optimum high power RF architecture for a high power SPL
Design, construction and test of superconducting RF cavities
(704 MHz – 5 cells – b=1)
Development of high power RF coupler, HOM damper and adaptation of tuner
Upgrade of the SM18 test place [2 K cooling + pulsed RF source at
704 MHz 50 Hz )]
Pulsed high power RF tests of contiguous cavities in a single cryostat
Design, construction and test a high power klystron modulator
Design, construction and test of a prototype cryomodule equipped with 8 b=1 cavities
Treated in sLHC-PP
Partly addressed in “EuCARD”
Partly supported by French “in-kind” contrib.
SPL R & D status and plans
Partly supported by ESS

20. ~ In-phase with ESS design update
Planning for cavities and cryomodule
2011
2012
2013
2014
2015 Q1 Q2 Q3 Q4
SM18 - 2K Cryogenics V
cryo. X
SM18
modulator 1 2
SM MHz High Power RF
High Power RF couplers 4
>4
>8
Superconducting
cavities
Assembled string of 4 cavities
Horiz. short cryom. (4 cav.)
Equipped horiz. short cryom.
High power RF tests in short cryo.
Assembled string of 8 cavities
8 cavities cryomodule
Equipped cryomodule
High power RF tests in full CM
CERN design
From ESS
~ In-phase with ESS design update

21. THANK YOU
FOR YOUR ATTENTION!

22. Spares

23. ISOLDE & EURISOL RADIOACTIVE IONS LINAC EURISOL EXPERIMENTAL HALLS
TARGETS
EURISOL EXPERIMENTAL HALLS
ISOLDE OR
EURISOL HIGH ENERGY EXPERIMENTAL HALL
TRANSFER LINE SPL to ISOLDE
TRANSFER LINES SPL to EURISOL

24. MUON PRODUCTION TARGET ACCUMULATOR & COMPRESSOR
Neutrino Factory
MUON ACCELERATORS
MUON PRODUCTION TARGET
MUON STORAGE RING
ACCUMULATOR & COMPRESSOR
SPL