Transcript Linear Collider – Next Steps in R&D Nan Phinney SLAC many slides courtesy of G.

Linear Collider – Next Steps in R&D
Nan Phinney
SLAC
many slides courtesy of G. Geshonke EPS 2009
C. Adolphsen, F. Zimmermann and others
Linear Collider Luminosity
where
nb : bunches / train
N: Particles / bunch
A: beam cross section at IP
HD: beam-beam enhancement factor
BUT
Pbeam = Pwall plug * ηconversion efficiency
two-linac length 2L ~ ECM/(Ffilling factor x Ggradient)
This points to the critical issues in optimizing the cost of the collider
→ Efficiency sets the electrical power required for a given beam power
→ Accelerating gradient sets the length required for a given energy
ILC & CLIC take different routes to high efficiency and high gradient
2009 SLUO Meeting Sept 17, 2009
Page 2
The ILC Reference Design
~31 km
200-500 GeV centre-of-mass
Luminosity: 2×1034 cm-2s-1
Based on accelerating gradient of 31.5 MV/m
(1.3GHz SCRF)
2009 SLUO Meeting Sept 17, 2009
N.Walker
Page 3
SCRF Technology Required
Parameter
C.M. Energy
Value
500 GeV
Peak luminosity
2x1034 cm-2s-1
Beam Rep. rate
5 Hz
Pulse time duration
1 ms
Average beam current
9 mA
Av. field gradient
31.5 MV/m
(in pulse)
# 9-cell cavity
14,560
# cryomodule
1,680
# RF units
560
A. Yamamoto
2009 SLUO Meeting Sept 17, 2009
Page 4
BREAKING NEWS !!!!
JLAB press release today announced the
first US built cavity to reach ILC specs
R. Geng, JLab
2009 SLUO Meeting Sept 17, 2009
Page 5
SRF Test Facilities
FNAL
NML facility
Under construction
first beam 2010
ILC RF unit test
A. Yamamoto
DESY

TTF/FLASH
~1 GeV
ILC-like beam
ILC RF unit
KEK, Japan

STF (phase I & II)
Under construction
first beam 2011
ILC RF unit test
(* lower gradient)
2009 SLUO Meeting Sept 17, 2009
Page 6
New L-Band Station at ESB: Marx Modulator and 10
MW Toshiba Multi-Beam Klystron
C. Adolphsen
2009 SLUO Meeting Sept 17, 2009
Page 7
Sheet Beam Klystron Development
Magnetic
Shielding
Lead
Shielding
RF cavity
Electron
Beam
Permanent
Magnet Cell
An elliptical beam is focused in a
periodic permanent magnet stack
that is interspersed with rf cavities
Gun in assembly
2009 SLUO Meeting Sept 17, 2009
Page 8
Coupler Assembly and Processing
Processed in
pairs – shipped
to FNAL
Class 10 Cleanroom @SLAC
2009 SLUO Meeting Sept 17, 2009
Page 9
RF Distribution Modules with variable tap off
Variable tap off allows power
adjustment to each cavity
4 2-cavity modules sent to FNAL
2009 SLUO Meeting Sept 17, 2009
Page 10
RDR Baseline Tunnel Layout
Two 4.5 to 5.5 m diameter
tunnels spaced by ~7 m.
Accelerator Tunnel
Penetrations
(every ~12 m)
Service Tunnel
one klystron feeding
26 cavities
C. Adolphsen
2009 SLUO Meeting Sept 17, 2009
Page 11
Klystron Cluster Concept
RF power “piped” into
accelerator tunnel every
2.5 km
Service tunnel eliminated
Electrical and cooling
systems simplified
Concerns: power handling,
LLRF control
coarseness
Same as baseline
C. Adolphsen
2009 SLUO Meeting Sept 17, 2009
Page 12
ILC R&D plan
2009 SLUO Meeting Sept 17, 2009
Page 14
14
The CLIC Two Beam Scheme
CLIC parameters:
Accelerating gradient: 100 MV/m
RF frequency: 12 GHz
Pulse length 240 ns, 50 Hz
active length for 1.5 TeV: 15 km
Two Beam Scheme:
Drive Beam supplies RF power
• 12 GHz bunch structure
• low energy (2.4 GeV - 240 MeV)
• high current (100A)
G. Geshonke
2009 SLUO Meeting Sept 17, 2009
Page 15
CLIC Drive Beam generation
Accelerate long bunch train with
low bunch rep rate (500 MHz)
with low frequency RF (1 GHz)
(klystrons)
interleave bunches between each other
to generate short (280 ns) trains with
high bunch rep rate (12 GHz)
G. Geshonke
2009 SLUO Meeting Sept 17, 2009
EPS 2009 G.Geschonke, CERN
Page 16
The full CLIC scheme
326 klystrons
33 MW, 139 s
326 klystrons
33 MW, 139 s
combiner rings
drive beam accelerator
2.38 GeV, 1.0 GHz
drive beam accelerator
2.38 GeV, 1.0 GHz
Circumferences
delay loop 72.4 m
CR1 144.8 m
CR2 434.3 m
1 km
delay
loop
delay
loop
CR2
CR2
CR1
1 km
CR1
decelerator, 24 sectors of 876 m
245m
TA
R=120m
BDS
2.75 km
BDS
2.75 km
BC2
e-
IP
main linac , 12 GHz, 100 MV/m, 21.02 km
245m
e+ main linac
TA
R=120m
48.3 km
CLIC 3 TeV
Not to scale!
BC2
booster linac,
9 GeV
e- injector
2.4 GeV
BC1
ePDR
365m
eDR
365m
e+
DR
365m
e+
e+ injector,
2.4 GeV
PDR
365m
2009 SLUO Meeting Sept 17, 2009
G. Geshonke
Page 17
optimum CLIC: 100 MV/m at 12 GHz
Optimisation:
Structure limits:
• RF breakdown – scaling
• RF pulse heating
Beam dynamics:
• emittance preservation – wake fields
• Luminosity, bunch population, bunch spacing
• efficiency – total power
Figure of merit:
• Luminosity per linac input power
take into account cost model
100 MV/m 12 GHz chosen,
previously 150 MV/m, 30 GHz
A. Grudiev
2009 SLUO Meeting Sept 17, 2009
Page 18
CLIC Accelerating Module
Transfer lines
Drive Beam
G. Riddone
Main Beam
19
2009 SLUO Meeting Sept 17, 2009
Page 19
CLIC Accelerating structures
Objective:
• Withstand 100 MV/m without damage
• breakdown rate < 10-7
• Strong damping of HOMs
Technologies:
Brazed disks - milled quadrants
W. Wunsch
Collaboration: CERN, KEK, SLAC
2009 SLUO Meeting Sept 17, 2009
Page 20
Nominal performance of Accelerating Structures
Design@CERN, Built/Tested @KEK, SLAC
10
BKD Rate for 230ns
-4
BKD Rate: 1/pulse/m
SLAC
BDR(ACC)
10
900hrs
10
1200hrs
-6
BDR_252nsec
090411-090414
10
-7
95
090403-090407
10-5
090402-090403
BDR(ACC)
-5
250hrs
0.0001
KEK
500hrs
090401-090402
090227-090305
100
105
110
Unloaded Gradient: MV/m
CLIC
target
090313-090323
-6
10
090501-090507
Eacc are a little shifted artificilally
to show error bars clearly
y = 3.0827e-19 * e^(0.28174x)
-7
10
80
85
90
95
100
105
110
115
120
R= 0.99488
2009 SLUO Meeting Sept 17, 2009
Eacc
Page 21
115
Power Extraction : PETS
Special development for CLIC
Travelling wave structures
Small R/Q : 2.2 kW/m
8 Sectors
damped
136 MW RF @ 240 ns per PETS
(2 accelerating structures)
(accelerating structure: 15-18 kW/m)
0.21 m active length
100 A beam current
total number : 35’703 per linac
on-off possibility
I. Syratchev
Status:
CTF3: up to 45 MW peak (3 A beam,
recirculation)
SLAC: 125 MW @ 266 ns
2009 SLUO Meeting Sept 17, 2009
Page 22
Power Extraction Structures (PETS)
PETS 1st run (winter 2008/09)
(Previously
considered
PETS a
significant
risk)
PETS 2nd run (May 2009…)
200
180
266 ns
133 ns
266 ns
160
153 MW (CLIC 0.5 TeV target)
12.05.09
Power [MW]
135 MW (CLIC 3 TeV target)
TBTS PETS,
140 ns flat,
25 minutes.
F. Zimmermann
150
Hours Sept 17, 2009
2009 SLUO
Meeting
210 Hours
Page 23
CLIC Test Facility CTF3
Provide answers for CLIC specific issues
 Write CDR in 2010
Two main missions:
Prove CLIC RF power source scheme:
• bunch manipulations, beam stability,
• Drive Beam generation
• 12 GHz extraction
Demonstration of “relevant” linac sub-unit:
• acceleration of test beam
Provide RF power for validation of
CLIC components:
accelerating structures,
RF distribution,
PETS (Power extraction and Transfer
Structure)
G. Geshonke
2009 SLUO Meeting Sept 17, 2009
Page 24
CTF3 building blocks
Infrastructure from LEP
30 GHz test stand
PULSE COMPRESSION
FREQUENCY MULTIPLICATION
magnetic chicane
150 MeV e-linac
3.5 A - 1.4 s
Delay Loop
F D
F
D
F
D
F
F
D
D
F
D
F
D
F
F
D
DF
D
F
F
DFD
DFD
FD
DFD
DFD
D F D
Combiner Ring
DF
D
FD
F
D
F
Photo injector tests,
laser
10 m
CLEX (CLIC Experimental Area)
TWO BEAM TEST STAND
PROBE BEAM
Test Beam Line
28 A - 140 ns
total length about 140 m
2009 SLUO Meeting Sept 17, 2009
Page 25
G. Geshonke
Delay Loop
circumference 42 m (140 ns)
isochronous optics
wiggler to tune path length
(9 mm range)
Designed and built by INFN Frascati
1.5 GHz RF deflector
G. Geshonke
2009 SLUO Meeting Sept 17, 2009
Page 26
Other R&D on performance issues
R&D on Damping Rings and Beam Delivery
in other test facilities:
CESR-TA at Cornell: Electron Cloud mitigation and
low emittance tuning
ATF/ATF2 at KEK: Low emittance damping ring
Final focus test facility to demonstrate
nanometer beam sizes and stability
2009 SLUO Meeting Sept 17, 2009
Page 28
Electron cloud mitigation R&D: PEP-II chicane
Mitigation tests
in ILC magnetic field
M. Pivi
Aluminum surface
New 4-dipole chicane in the PEP-II LER
TiN surface much reduced
signal with respect to Al
Test chamber Al and TiN-coated
Observed new resonance: Electron
current peaks at defined B values (n)
2009 SLUO Meeting Sept 17, 2009
Page 29
ILC Damping Ring R&D
11 very high priority R&D items to be addressed for the ILC technical design:
Lattice design for baseline positron ring
Lattice design for baseline electron ring
Demonstrate < 2 pm vertical emittance
Characterize single bunch impedance-driven instabilities
Characterize electron cloud build-up
Develop electron cloud suppression techniques
Develop modelling tools for electron cloud instabilities
Determine electron cloud instability thresholds
Characterize ion effects
Specify techniques for suppressing ion effects
Develop a fast high-power pulser
Targeted for CesrTA
Targeted for
ATF Effort
Effort with Low
Emittance e+ Beam
M. Palmer
2009 SLUO Meeting Sept 17, 2009
Page 30
ATF2
Beamline, January 2008
May 2008
Summer 2007
Model of ILC
final focus
HA PS
ATF2 goals :
(A) Small beam size ~37nm
(B) nm stability of beam center
ATF international collaboration: MOU signed by 20 institutions
ATF2 constructed as ILC model, with in-kind contributions
Start of beam commissioning: October 2008
2009 SLUO Meeting Sept 17, 2009
A. Seryi
FD integration
Page 31
ILC – CLIC collaboration
CLIC
ILC
Physics & Detectors
L.Linssen, D.Schlatter
F.Richard, S.Yamada
Beam Delivery System (BDS) &
Machine Detector Interface
(MDI)
D.Schulte,
R.Tomas Garcia
E.Tsesmelis
B.Parker, A.Seriy
Civil Engineering &
Conventional Facilities
C.Hauviller, J.Osborne.
J.Osborne,
V.Kuchler
Positron Generation (new)
L.Rinolfi
J.Clarke
Damping Rings (new)
Y.Papaphilipou
M.Palmer
Beam Dynamics
D.Schulte
A.Latina, K.Kubo, N.Walker
Cost & Schedule
P.Lebrun, K.Foraz,
G.Riddone
J.Carwardine, P.Garbincius,
T.Shidara
2009 SLUO Meeting Sept 17, 2009
Page 32
GDE: ILC Timeline
2005
2006
2007
2008
2009
2010
2011
2012
2013
GDE process
Reference Design Report (RDR)
Tech. Design Phase (TDP) 1
TDP 2
LHC physics
Ready for Project
Submission
B. Barish
We are here
April 2009
2009 SLUO Meeting Sept 17, 2009
Page 33
Tentative long-term CLIC scenario
Shortest, Success Oriented, Technically Limited Schedule
Technology evaluation and Physics assessment based on LHC results
for a possible decision on Linear Collider with staged construction
starting with the lowest energy required by Physics
2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
R&D on Feasibility Issues
Conceptual Design
R&D on Performance and Cost issues
Technical design
Engineering Optimisation&Industrialisation
Construction (in stages)
Construction Detector
G. Geshonke
Conceptual
Design
Report
(CDR)
Technical
Design
Report
(TDR)
2009 SLUO Meeting Sept 17, 2009
Project
approval ?
Page 34
First
Beam?
Summary
ILC: 500 GeV, upgradable to 1 TeV
Technology quite advanced. Much recent progress.
TDP plan to be ready for a proposal in 2013.
Key R&D: Cavity gradient, improved RF sources, electron cloud, BDS
CLIC: designed to reach 3 TeV, probably in stages
Still much R&D. CTF3 just coming on line.
TDR expected end 2015. Could be proposed in 2018?
Key R&D: Structure gradient & damping, PETS, drive beam generation,
also sources, damping rings and BDS issues
2009 SLUO Meeting Sept 17, 2009
Page 35