Plans for the upgrade of the CERN
complex of proton accelerators
R. Garoby
Content
Introduction (European Strategy & CERN white paper)
 Scenarios for the upgrade of the accelerators
 Linac4
 SPL & PS2
 Roadmap
 Summary

Introduction
INTRODUCTION
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Statement of the European Strategy Group (1/2)
 Consolidation
and upgrade of
injectors
 LHC upgrade
and maximum
performance
injectors
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Statement of the European Strategy Group (2/2)
 R & D for
LHC upgrade
and n facility
 preparation
for n facility
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“White Paper” (1/2)

Submitted for information and discussion
at the 139th meeting
of the CERN Council (19 October 2006)
Section 3: Further activities to be funded by additional resources
Total request: 240 MCHF during 2008-2010

Theme 1: consolidation and basic improvements:

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

Theme 2: renovation of the old injector complex:




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R & D on superconducting magnets, RF and cryogenics
R & D for LHC detectors
Increased support for CLIC
Theme 4: miscellaneous R & D:

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
R. G.
R & D for a new PS and his injector (SPL)
Construction of Linac4
Theme 3: R & D for LHC upgrade and CLIC:


Basic consolidation of existing accelerators
New power supply for the PS
New multi-turn ejection
Etc.
SC RF
High power target
ELENA, HIE ISOLDE, 3rd phase NA-48…
5
Material
(MCHF)
Personnel
(man.years)
103
246
55
185
58
212
41
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“White Paper” (2/2)

Submitted for information and discussion
at the 139th meeting
of the CERN Council (19 October 2006)
Section 4: Prospects over the period 2011-2016
1)
2) CLIC …
3) Infrastructure consolidation
4)
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SCENARIOS FOR THE
UPGRADE OF THE
ACCELERATORS
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CERN accelerator complex
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Upgrades of the accelerator complex
As proposed by the PAF working group
50 MeV
160 MeV
Output energy
1.4 GeV
~ 5 GeV
26 GeV
40 – 60 GeV
450 GeV
1 TeV
7 TeV
~ 14 TeV
R. G.
Linac2
Proton flux / Beam power
Linac4
SPL’
RCPSB
PSB
PS
SPL
PS2 (PS2+)
SPS
LHC /
SLHC
9
SPS+
DLHC
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)
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Benefits for physics
STAGE
1
3
4
DESCRIPTION
Linac4
PSB
PS
SPS
Linac4
SPL
PS2 or PS2+
SPS
Linac4
SPL
PS2 or PS2+
SPS+
Performance of LHC
injectors (SLHC)
+
Ultimate beam from
PS
++
Maximum SPS
performance
+++
Highest performance
LHC injector
Higher energy LHC
-
-
+++
b beam
-
++ (g ~100)
++ (g ~200)
n Factory
-
+++ (~5 GeV prod.
beam)
+++ (~5 GeV prod.
beam)
k, m
-
~400 kW beam at
50 GeV
~400 kW beam at
50 GeV
EURISOL
-
+++
+++
(new accelerator)
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Layout of the new LHC injectors
SPS
PS2
SPL
PS
Linac4
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Proton driver for a n Factory & EURISOL
Connection
PS2 -> TT70
SPL
Accumulator &
Compressor
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Possible layout of a n Factory
m
accelerator
Target
SPL
m
storage
ring
Based on CERN scheme in 2001
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LINAC4
Technical Design Report (December 2006)
CERN-AB-2006-084, http://cdsweb.cern.ch/record/1004186
L. Arnaudon, P. Baudrenghien, M. Baylac, G. Bellodi, Y. Body, J. Borburgh, P. Bourquin, J. Broere,
O.Brunner, L. Bruno, C. Carli, F. Caspers, S.; Cousineau, Y. Cuvet, C. De Almeida Martins, T. Dobers,
T. Fowler, R. Garoby, F. Gerigk, B. Goddard, K. Hanke, M. Hori, M. Jones, K. Kahle, W. Kalbreier, T.
Kroyer, D. Küchler, A.M Lombardi, L.A López-Hernandez, M. Magistris, M. Martini, S. Maury, E.Page,
M. Paoluzzi, M. Pasini, U. Raich, C. Rossi, J.P Royer, E. Sargsyan, J. Serrano, R. Scrivens, M. Silari,
M. Timmins, W.Venturini-Delsolaro, M. Vretenar, R. Wegner, W. Weterings, T. Zickler
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Linac4 parameters
Ion species
H−
Output Energy
160
MeV
Bunch Frequency
352.2
MHz
Max. Rep. Rate
2
Hz
Beam Pulse Length
400
ms
Max. Beam Duty Cycle
0.08
%
Chopper Beam-on Factor 62
%
Chopping scheme:
222 transmitted /133 empty buckets
Source current
80
mA
RFQ output current
70
mA
Linac current
40
mA
N. particles per pulse
1.0
× 1014
Transverse emittance
0.4
p mm mrad
Max. rep. rate for accelerating structures
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50 Hz
Will re-use 352 MHz LEP
RF components: klystrons,
waveguides, circulators.
2 operating modes: low duty
for PS Booster (PSB)
injection in the first phase,
high duty for the SPL in a
second phase.
Structures and klystrons
dimensioned for 50 Hz
Power supplies and
electronics dimensioned for
2 Hz.
IDS meeting - CERN – 29 March 2007
Linac4 topology
95keV
HRF
volume
source
(DESY)
35 kV
Extrac.
60kV
Postacc.
RFQ
3MeV
CHOPPER
Radio
Frequency
Quadrupole
(IPHI)
352 MHz
6m
1 Klystron
1 MW
Total Linac4:
80 m,
18 klystrons
R. G.
3MeV
Chopper
352 MHz
3.6 m
11 EMquad
3 rf cavity
40MeV
DTL
Drift Tube
Linac
352 MHz
13.4 m
3 tanks
5 klystrons
4 MW
82 PMQuad
90MeV
160MeV
CCDTL
SCL
Cell-Coupled
Drift Tube
Linac
352 MHz
25.3 m
24 tanks
8 klystrons
6.5 MW
24 EMQuads
Side Coupled
Linac
Duty cycle:
0.1% phase 1 (Linac4)
3-4% phase 2 (SPL)
(design: 15%)
704 MHz
28 m
20 tanks
4 klystrons
12 MW
20 EMQuads
4 different structures,
(RFQ, DTL, CCDTL, SCL)
2 frequencies
current: 40 mA (avg. in
pulse), 65 mA (bunch)
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The 3 MeV Test Stand
In construction, first beam
foreseen in 2008.
- H- source (DESY type,
- LEBT (2 solenoid)
- IPHI RFQ
- Chopper line (from CERN)
- Diagnostics line (IPHI and
CERN components)
- Infrastructure (1 LEP Klystron,
pulsed power supply, etc.)
Beam quality is generated in
the front-end.
=> Its early understanding and
optimisation is fundamental for
a modern linac project.
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The IPHI RFQ
The 3 MeV Test Stand, Linac4 and finally
SPL will use an RFQ built with IPHI
technology (brazing at CERN).
The RFQ is expected at CERN before the
end of 2008.
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The 3 MeV chopper line
Compact design 3.7 m length
Dynamic range 20 – 60 mA
Small e growth 4% long.,
8% trans.
Tolerant to alignment errors
Dumping of chopped
beam and collimation of
unchopped beam in a
conical dump structure
Chopper structure: double
meander strip line, 400mm
length, metallized ceramic
plate. 2 ns rise/fall time for
bunch selectivity (352 MHz
beam structure), ±500V
between deflecting plates.
3 RF bunchers
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Cell Coupled DTL
Used above 40 MeV:
focusing periods can be longer  structure
with external quadrupoles, placed
between short DTL-like tanks
With respect to DTL: can use electromagnets, easy access and cooling,
easier machining and alignment,
simpler and more economic
construction
Modules of 3 tanks connected by coupling
cells, 2 drift tubes per tank
High-power prototype tested at CERN
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Beam dynamics, aperture and beam size
Large apertures (>5 times
rms beam size) to minimise
losses.
Scraping foreseen to
reduce maximum beam
size in presence of errors.
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SPL
Conceptual Design Report (July 2006)
CERN-2006-006, http://cdsweb.cern.ch/record/975366
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 Naples) ; 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;
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SPL New Layout (CDR2, 2006)
LINAC4
New SPL Design (CDR2, CERN Yellow Report 2006-006):
Linac4 (extended to 180 MeV) + 2 superconducting
sections based on 5-cell elliptical cavities at 704 MHz
(INFN/CEA).
Long cryomodules (LHC/TESLA-like, 12-14m), 6-8
cav./module, cold quads in cryomodules
Overall length 430m (for 3.5 GeV, was 690m in previous
version for 2.2 GeV)
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Medium
b
High
b
Cavity b
0.65
1
R/Q (Ohm)
235
575
Aperture
(mm)
85
90
Ep/Eacc
2.6
2.4
Eacc (MV/m)
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SPL Beam parameters
CDR2
“slim-SPL” for
SPS & LHC
“MW-SPL”
3.5
4-5
5
Beam power (MW)
4
0.15 – 0.19
4-8
Rep. frequency (Hz)
50
2
50
Protons/pulse (x 1014)
1.4
1.2
1
Av. Pulse current
40
10
40
Pulse duration (ms)
0.57
1.9
0.4
Bunch frequency (MHz)
352.2
352.2
352.2
430
~460
535
Energy (GeV)
Physical length (m)
3 different designs:
CDR2 (2006) based on 700 MHz high-gradient cavities
“slim-SPL” for LHC (2007) with low beam power, for the needs of the LHC
“MW-SPL” at higher energy, for the needs of neutrino production
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SPL cavities: elliptical, 704 MHz
Elliptical cavities at b=0.5 (CEA, INFN) are giving
promising results. Stiffened for pulse operation.
Length ~ 0.9m
Designed for 12 MV/m.
cryomodule
1m
1m
diagnostics,
steering
10 to 15 m
* Feed 4 to 6 cavities per
klystron: use high power phase
and amplitude modulators.
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SPL Beam Dynamics
Control of losses, minimization of the emittance growth and halo development.
1)
2)
3)
zero current phase advance always below 90 degrees, for stability;
longitudinal to transverse phase advance ratio (with current) between 0.5
and 0.8 in order to avoid resonances
smooth variation of the transverse and longitudinal phase advance per
meter.
250
phase advance [deg/m]
kx
ky
200
kz
150
100
50
0
0
10
20
30
40
50
60
70
position [m]
Smooth phase advance variation
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Selection of the working point (phase
advances) on the Hofmann’s chart
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PS2
Working group started at end 2006
Benedikt, M; Fabich, A; Goddard, B; Hancock, S; Jowett, J; Laface, E
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Justifications of PS2

Assure high reliability and availability of injector chain for
LHC operation



Replace the PS !
Increase performance of injector chain for LHC operation


Higher beam brightness by more favourable energy range
Shorter filling time by improved cycling schemes

Improve performance for other physics applications in
energy range PS to SPS (10 to 450 GeV).

Prepare long-term (energy) upgrade of complete accelerator
chain

R. G.
PS main magnet coils and laminations
Rotating machine main power converter
Higher PS2 ejection energy to reduce SPS+ energy swing
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PS2 design goals

Beam brightness for LHC:


Reach twice brightness of the ultimate 25 ns LHC beam (20% reserve for
losses): 4.01011 per LHC bunch (inst. 1.71011)
“Ultimate“ bunches at 12.5 ns, twice ultimate at 25ns, etc.


Significantly higher injection energy into SPS (~50 GeV).




Injection into SPS well above transition energy
Reduced space charge at SPS injection
Smaller transverse emittances and reduced losses
Potential for long-term SPS replacement with higher energy.


Ejection energy determines PS2 machine size
As versatile as existing PS

R. G.
Determines average line density in the machine at injection and therefore the
injection energy via incoherent SC tune spread.
Protons, ions, high intensity physics beams, slow extraction, etc.
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Considerations on PS2 size

Existing PS with 25 GeV top energy:





Combined function magnets with classical lattice.
Bending radius of 70 m (~440 m length) (B = 1.25 T at 25 GeV)
114 m (174 m) of (fully used) straight sections.
Average radius 100 m and machine circumference 628 m.
PS2: extraction energy ~50 GeV (NC)

Separated function (eventually complicated lattice for imag. gt)




Assume quads will occupy 30 % of integrated dipole length
NC: dipole at ~ 1.8 T (i.e. bending radius ~100 m, length ~ 630 m)
Additional space for quadrupoles: ~200 m
Larger space requirements for insertions: ~300m
 PS2 will have ~twice PS radius i.e. 200 m and 1250 m length
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Considerations on PS2 injection energy

Incoherent space charge tune spread at injection:

Existing PS with 1.4 GeV injection energy just capable of
producing the ultimate LHC beam (DQv ~-0.3)
DQS.C.  
Nb 1 1
 2
en bg B b
Bb… bunching factor (average / peak density for single bunch)
 Bb will decrease by factor 2 when putting the same bunch in a
machine with twice larger circumference (DQ increases with R)!


PS2: twice ultimate brightness in a twice larger
machine


4 times larger incoherent tune spread at given energy.
Compensation with ratio bg2 at injection:

R. G.
Minimum injection energy PS2: 3.5 to 4 GeV
31
bg 
2
PS 2
 
 4  bg 2
PS
IDS meeting - CERN – 29 March 2007
PS2 preliminary parameters
PS
PS2
3.5 – 4.0
1.4
~ 50
13/25
~ 1346
628
Maximum intensity LHC (25ns) (p/b)
4.0 x 1011
1.7 x 1011
Maximum intensity for fixed target physics (p/p)
1.2 x 1014
3.3 x 1014
1000
70
1.5
2.2
~ 2.5
1.2/2.4
400
60
Injection energy kinetic (GeV)
Extraction energy kinetic (GeV)
Circumference (m)
Maximum energy per beam pulse (kJ)
Max ramp rate (T/s)
Repetition time at 50 GeV (s)
Max. effective beam power (kW)
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ROADMAP
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Linac4 project

2007

 mid-2007




July  September 2007







R. G.
Progressive beam commissioning of Linac4
Mid-2011


Start of Civil Engineering
Start of construction of Linac4 equipment
Mid-2010


Project review
Project organization inside CERN
January 2008: official start of the Linac4 project


Finalization of the design (updated design report)
Conclusion on allocation of work packages / distribution of « remaining » tasks
inside CERN
Market survey for Civil Engineering
September  December 2007


Optimization of the layout on the CERN site
Negotiation of detailed work packages with external partners
CERN Council decision on the « White paper »
PSB stop for modification
PSB beam commissioning
Beginning 2012: PSB operational for physics with Linac4
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Preparation for the SLHC

 end 2010 for LHC and SPS








Selection of the most promissing scenarios for the LHC upgrade
Experience with the LHC and its practical limitations…
Detailed technical design of the LHC upgrade
Detailed technical design of the SPS upgrade
Prototyping of critical components
Detailed estimates of the necessary resources
Negotiation with external contributors
 end 2010 for the injectors of SPS







Optimization of the layout on the CERN site
Optimization of compatibility with other users (EURISOL, n’s, pbars, heavy ions…)
Detailed technical design
Prototyping of critical components
Detailed Civil Enginering drawings
Detailed estimates of the necessary resources
Negotiation with external contributors
 publication of Technical Design Reports with resources estimates
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Implementation of the LHC luminosity upgrade

2011  2015 for LHC and SPS



2011  2015 for the injectors of SPS




Construction of SPL and PS2
Progressive beam commissioning of SPL
Beam commissioning of PS2
2016



R. G.
Construction of components for the LHC and SPS upgrade
Progressive modification of the SPS (vacuum chamber treatment, impedance
reduction etc.)
Connection of PS2 to SPS & final modifications of the SPS (injection system etc.)
Beam commissioning of the SPS
Beam commissioning of the LHC
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Planning of the new injectors
3 MeV test
place ready
Linac4
approval
CDR 2
SPL & PS2 approval
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SUMMARY
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
CERN is soon going to commission the largest and
most sophisticated particle accelerator ever built.
Such an installation must be fully exploited.
 It is time to prepare for securing its operation, increasing the
reliability of all the infrastructure for protons and ions.
 It is time to develop solutions for pushing performance to the
limit.
 It is a unique opportunity to plan new accelerators that can satisfy
a new generation of physics experiments.
Mid-2007 is a first crucial milestone in an overall
planning that should last for a decade.
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