Roger M. Jones
Cockcroft Institute and
The University of Manchester
1


Roger M. Jones (Univ. of Manchester faculty)
 Alessandro D’Elia (Dec 2008, Univ. of Manchester PDRA based at CERN)

Vasim Khan (PhD student, Sept 2007)

Part of EuCARD ( European Coordination for Accelerator
Research and Development) FP7 NCLinac Task 9.2
V. Khan, CI/Univ. of
Manchester Ph.D. student
A. D’Elia, CI/Univ. of
Manchester PDRA based at CERN (former CERN
Fellow).

Collaborators: W. Wuensch, A. Grudiev, I. Syrachev, R.
Zennaro, G. Riddone (CERN)
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 2

Three Main Parts:
1. Review of salient features of manifold damped and detuned linacs.
2. Initial designs (three of them).

CLIC_DDS_C.
3. Further surface field optimisations

CLIC_DDS_E(R).
4. Finalisation of current design. Based on moderate damping on strong detuning. Single-structure based on the eight-fold interleaved for HP testing

CLIC_DDS_A
5. Concluding remarks and future plans.
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 3

1. Introduction –Present CLIC baseline vs. alternate DDS design

The present CLIC structure relies on linear tapering of cell parameters and heavy damping with a Q of ~10.
 Wake function suppression entails heavy damping through waveguides and dielectric damping materials in relatively close proximity to accelerating cells.

Alternative scheme, parallels the DDS developed for the
GLC/NLC, entails:
1. Detuning the dipole bands by forcing the cell parameters to have a precise spread in the frequencies –presently Gaussian
Kdn/dfand interleaving the frequencies of adjacent structures.
2. Moderate damping Q ~ 500-1000
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 4

Acceleration cells
Manifold
1. Features of CLIC DDS
Accelerating Structure
HOM coupler
Beam tube
 SLAC/KEK RDDS structure (left ) illustrates the essential features of the conceptual design
 Each of the cells is tapered –iris reduces (with an erf-like distribution –although not unique)
 HOM manifold running alongside main structure removes dipole radiation and damps at remote location (4 in total)
High power rf coupler
 Each of the HOM manifolds can be instrumented to allow:
1) Beam Position Monitoring
2) Cell alignments to be inferred
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 5

1. Features of DDS
Accelerating Structure –GLC/NLC
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 6

1. Determination of Cell Offset From Energy Radiated
Through Manifolds –GLC/NLC
Refs: ??????
Dots indicate power minimisation
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 7

1. GLC/NLC Exp vs Cct Model Wake
DDS1
DDS3
(inc 10MHz rms errors)
RDDS1 Q cu
DS
H60VG4SL17A/B
-2 structure interleaved
ASSET
Data
RDDS1
Conspectus of GLC/NLC Wake Function Prediction and Exp. Measurement (ASSET dots)
Refs: 1. R.M. Jones,et al, New J.Phys.11:033013,2009.
2. R.M. Jones et al., Phys.Rev.ST Accel. Beams 9:102001, 2006.
3. R.M. Jones, Phys.Rev.ST Accel. Beams, Oct.,2009.
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 8

1. CLIC Design Constraints
1) RF breakdown constraint
E max sur

260
2) Pulsed surface temperature heating

T max 
56 K
3) Cost factor
P in
3
 p
C in

18
Beam dynamics constraints
1) For a given structure, no. of particles per bunch N is decided by the
<a>/λ and Δa/<a>
2) Maximum allowed wake on the first trailing bunch
W t 1

  9
( /[ .
. ])
N
Wake experienced by successive bunches must also be below this criterion
Ref: Grudiev and Wuensch, Design of an x-band accelerating structure for the CLIC main linacs, LINAC08
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 9

2.0 Initial CLIC_DDS Designs
Three designs
1. Initial investigation of required bandwidth to damp all bunches (~3GHz)
2. New design, closely tied to CLIC_G (similar iris  a), necessitates a bandwidth of ~ 1 GHz. Geometry modified to hit bunch zero crossings in the wakefield .
3. Relaxed parameters, modify bunch spacing from 6 to 8 rf cycles and modify bunch population. Wake wellsuppressed and seems to satisfy surface field constraints.
CLIC_DDS_C (  f ~ 3.6
 , 13.75%).
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 10

2.1 Initial CLIC_DDS Design –  f determination
Structure
Frequency (GHz)
Avg. Iris radius/wavelength
<a>/λ
CLIC
_G
12
0.11
Input / Output iris radii
(mm)
3.15,
2.35
Input / Output iris thickness (mm)
1.67,
1.0
Group velocity (% c) 1.66,
0.83
No. of cells per cavity
Bunch separation (rf cycles)
No. of bunches in a train
Lowest dipole
∆f ~ 1GHz
Q~ 10
CLIC_G
24
6 Bandwidth Variation
Truncated Gaussian :

Variation
312 2
 t
 2
W t

2Ke
  n

  t / 2 2
 
  where : (t, f )

CLIC_DDS Uncoupled Design
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland

2. Initial design for CLIC DDS
First dipole Uncoupled, coupled.
Dashed curves: second dipole

8-fold interleaving employed

Finite no of modes leads to a recoherance at ~ 85 ns.

For a moderate damping Q imposed of ~1000, amplitude of wake is still below 1V/pc/mm/m

3.3 GHz structure does satisfy the beam dynamics constraints

However, it fails to satisfy RF breakdown constraints as surface fields are unacceptable.
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 12

2.2 Gaussian linked to CLIC_G parameters
–Zero Crossings
Coupled
Uncoupled params:
<a>/λ=0.102
∆f = 3σ = 0.83 GHz
∆f/<f>= 4.56%
Uncoupled

Systematically shift cell parameters (aperture and cavity radius) in order to position bunches at the zero crossing in the amplitude of the wake function.
Amplitude Wake
Q = 500

Efficacy of the method requires a suite of simulations in order to determine the manufacturing tolerances.
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 13

2.3 Relaxed parameters tied to surface field constraints
(f/<f> = 13.75 %)
Uncoupled parameters
Cell 1
• Iris radius = 4.0 mm
Cell 24
•
Iris radius = 2.13 mm
•
Iris thickness = 4.0 mm , • Iris thickness = 0.7 mm,
• ellipticity = 1 • ellipticity = 2
• Q = 4771 •
Q = 6355
• R’/Q = 11,640 Ω/m • R’/Q = 20,090 Ω/m
• vg/c = 2.13 %c • vg/c = 0.9 %c
Cct Model Including Manifold-
Coupling

Employed spectral function and cct model, including Manifold-
Coupling, to calculate overall wakefunction.
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland 14

Cell parameters
Cell Parameters
Iris radius
Iris radius a min
, a max
= 4.0, 2.13
R b
Rc a a+a1
Cavity radius
Cavity radius t/2 b min
, b max
= 10.5, 9.53
a1
Sparse Sampled HPT
(High Power Test)
Fully Interleaved
8-structures
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland a
L
15

2.3 Relaxed parameters –full cct model
Coupled 3 rd mode
Uncoupled 2 nd mode
Uncoupled
1 st mode
Uncoupled 2 nd mode
Uncoupled
1 st mode
Coupled 3 rd mode
Uncoupled manifold mode
Avoided crossing
First Cell represented coupling (damping Q)
Light line
 Dispersion curves for select cells are displayed (red used in fits, black reflects accuracy of model)
 Provided the fits to the lower dipole are accurate, the wake function will be well-
 Spacing of avoided crossing (inset) provides an indication of the degree of
Avoided crossing
Uncoupled manifold mode
Mid-Cell
Light line
Uncoupled 2 nd mode
Uncoupled
1 st mode
Avoided crossing
Uncoupled manifold
End Cell mode
Light line
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland
Coupled 3 rd mode
16

Dipole mode
2.3 Summary of CLIC_DDS_C
Manifold mode
Manifold
Coupling slot
∆f=3.6 σ
=2.3 GHz
∆f/fc=13.75%
192 cells
8-fold interleaving
∆fmin = 65 MHz
∆tmax =15.38 ns
∆s = 4.61 m
Meets design
Criterion?
∆fmin = 8.12 MHz
∆tmax =123 ns
∆s = 36.92 m
24 cells
No interleaving
192 cells
8-fold interleaving
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland

3. CLIC_DDS_E

Enhanced H-field on various cavity contours results in unacceptable

T (~65 ° K).

Can the fields be redistributed such that a
~20% rise in the slot region is within acceptable bounds?

Modify cavity wall

Explore various ellipticities (R. Zennaro, A.
D’Elia, V. Khan)
International Workshop on Linear Colliders, 18 – 22 Oct. 2010, CERN, Switzerland

3. CLIC_DDS_E Elliptical Design
Circular
Square
ε 
4.14
Elliptical
Convex
Concave ε 
2.07
ε 

2

1
 a b b
ε 
1.38
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland a
19

3. CLIC_DDS_E Elliptical Design –E Fields
Circular
ε 
1
Single undamped cell
Iris radius=4.0 mm
Square
ε  
ε 
4 .
14
Convex ellipticity
ε 
2.07
ε 
1.38
ε=-8.28
Concave ellipticity
ε=-4.14
ε=-2.07
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
20

3 CLIC_DDS_E Elliptical Design, Single
Undamped Cell Dependence of Fields on

Circular Rectangular Elliptical
(Convex)
 of cavity 1
∞
4.14
2.07
1.38
0.82
0.41
Elliptical
(Concave)
-8.28
-4.14
f acc
(GHz) 12.24
12.09
11.98
12.0
11.99
11.98
11.98
11.9911
-2.07
11.9919
11.9935
Eacc(V/m) 0.43
0.43
0.42
0.43
0.43
0.42
0.42
0.43
0.43
0.42
H sur max
(mA/V)
/Eacc 3.64
E sur max
/E acc
2.27
4.86
2.27
4.71
2.33
4.54
4.29
3.75
3 4.94
2.28
2.28
2.33
2.33
2.27
4.99
2.27
5.11
2.33
Iris radius = 4. 0 mm
Iris thickness = 4.0 mm
Chosen design
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
21

3. CLIC_DDS_E Single-Cell Surface Field
Dependence on ε
Optimisation of cavity shape for min H max s
 Iris radius ~4mm. For both geometries

Averaging surface H over contour

=1.38
R ectangular
(
 =∞)
Circular
(

=1)
Circular cell
ε=1.38
ε=0.82
ε =0.82
ε=1.38
ε=0.41
ε=2.07
Optimised parameters
ε=4.14
for DDS2
Undamped cell
Manifold-damped single cell
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
22

3. CLIC_DDS_E, Optimisation of:
E max s
, ∆f and Efficiency

Optimisation of parameters based on manifold damped structures.

Vary half-iris thickness.

3-cell simulations, with intermediate parameters obtained via interpolation.

Choose parameters with minimal surface E-field, pulse temperature rise, and adequate efficiency.
Efficiency
∆T
P in
∆f dipole
Chosen optimisation
(CLIC_DDS_E)
E max s
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
23

3. CLIC_DDS_E: Detailed Geometry eminor

0 .
3
 emajor b 2 emajor
 b 2 r
2 h
1
2*r
2 r
1 r
1 h r
1
+h+2r
2
R c b
Radius = 0.5 mm g=L - t
L t= 2a
2 a
2 a a1 r1 h h1
Constant parameters
(mm)
L
All cells
8.3316
0.85
4.5
1.25
a2 a1
Rc r2
Variable parameters
(mm) a
Cell #1
4.0
b 11.01
2.0
a2
6.2
3.25
Fillet @ cavity and manifold joint
Rounding of cavity edge
1.0
0.5
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
Cell#24
2.3
10.039
0.65
2a2
6.8
2.3
24

3. Impact on Parameters:
CLIC_DDS_C to CLIC_DDS_E
DDS2_E
DDS1_C
DDS1_C
DDS2_E
Parameter DDS1_C DDS2_E Modified to achieve
Shape Circular
<Iris thickness> (mm) 2.35
Elliptical
2.65
Min. H-field
Min. E-field
R c
1to 24 (mm) 6.2-7.5
6.2-6.8
Critical coupling
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
25

3. CLIC_DDS_E
-Fundamental Mode Parameters
DDS1_C
DDS_E
Vg
R/Q
DDS1_C
DDS_E
Q
DDS_E
DDS1_C
 Group velocity is reduced due increased iris thickness
 R/Q reduced slightly
 Surface field and

T reduced significantly by using elliptical cells
DDS1_C
DDS_E
E s
DDS1_C
DDS_E
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
H s
26

3. Wake Function for CLIC_DDS_E
-Dipole Circuit Parameters

DDS_C
DDS_E
Cct

DDS_E
DDS1_C
 Avoided crossing
 x is significantly reduced due to the smaller penetration of the manifold.
 Some reoptimisation could improve this
DDS_C
DDS_E
Avoided
Crossing

∆f=3.5 σ
=2.2 GHz
∆f/f c
=13.75% a a
24
1
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
=4mm
=2.3mm
27

3. Consequences on Wake Function
Spectral Function Wake Function
DDS1_C
DDS2_E
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
28

4. CLIC_DDS_E: Modified Design
Based on Engineering Considerations
DDS2_E
DDS2_ER
Rounding necessitates reducing this length
(moves up)

R c
Rounding
 To facilitate machining of indicated sections, roundings are introduced (A.
Grudiev, A. D’Elia).
 In order to accommodate this, R c needs to be increased

DDS2_ER.
 Coupling of dipole modes is reduced and wake-suppression is degraded. How
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
29 much?

4. CLIC_DDS_ER Dispersion Curves
Uncoupled 2 nd
Dipole Mode
Cell # 1
Cell # 1
Uncoupled
Dipole mode 
Avoided crossing Light line
Line
Uncoupled manifold mode
Cell # 24

Cell # 24
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
30

4. CLIC_DDS_E vs CLIC_DDS_ER Wakefield
Spectral Function Wakefunction
CLIC_DDS_E :Rc=6.2 - 6.8 mm (optimised penetration)

CLIC_DDS_ER : Rc=6.8 mm const (a single one of these structures constitutes
CLIC_DDS_A, being built for HP testing)

Wakefield suppression is degraded but still within acceptable limits.
31

4. CLIC_DDS_A:
Structure Suitable for High Power Testing

Info. on the ability of the 8-fold interleaved structure to sustain high e.m. fields and sufficient

T can be assessed with a single structure.

Single structure will be fabricated this year

CLIC_DDS_A, to fit into the schedule of breakdown tests at CERN.

Design is based on CLIC_DDS_ER

To facilitate a rapid design, the HOM couplers will be dispensed with in this prototype.

Use mode launcher design

Status: rf design for main cells complete, matching cells in mode launcher almost complete.
 Mechanical drawings, full engineering design

EuCARD partners +
32
CERN

4. CLIC_DDS_A:
Structure Suitable for High Power Testing

Non-interleaved 24 cell structure
 High power (~71MW I/P) and high gradient testing

To simplify mechanical fabrication, uniform manifold penetration chosen
Cell # 24
Cell # 1
Illustration of extrema of the end cells of a 24 cell structure
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
33

International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
34

35*Sc
Eacc
Pin
∆T
Dashed curves : Unloaded condition
Solid curves: Beam loaded condition
Esur
Max. Values
Esur=220 MV/m
∆T = 51 K
Pin= 70.8
Eacc_UL=131 MV/m
Sc=6.75 W/μm 2
RF-beam-eff=23.5%
CLIC_G Values
Esur=240 MV/m
∆T = 51 deg.
Pin= 63.8
Eacc_UL=128 MV/m
Sc=5.4 W/μm 2
RF-beam-eff=27.7%
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
35

24 cells
No interleaving
Q avg
~1700
24 cells
No interleaving
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
Undamped
Damped
36

For each side of the structure (cell ♯ 1 and cell ♯ 24):
• We build a structure with one regular cell and two specular matching cell at its sides and we look at the minima S11 as a function of the geometrical parameters of the matching cells
• We do the same for a structure with two and three identical regular cells in the middle and still we look at minima S11
• The matching condition is the one common to the three cases
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
37

Port 2
E-fiel d Port 1
Beam
198.6326mm
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
38

V
26
[V]@P in
= 1 W
G
26
[V/m]@P in
= 1 W
P in
[MW]@<G
26
=100MV/m>
2678
13481
55.03
S12
S22
6165
@
11.9944G
Hz
S11
-
48.2dB@
11.9944GHz
39
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland

Water pipes for cooling
Vacuum flange
Tuning holes
Power output
Vacuum flange
Power input
Thanks to Vadim Soldatov
Cut-view
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
40

International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
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International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
42

•
Power absorbed in the breakdown has quadratic dependence on the fundamental mode group velocity
•
High Phase Advance (
5π/6
) operation will reduces the group velocity of the fundamental mode
•
Hence the breakdown events in HPA structure are less likely expected compared to the standard (
2π/3
) structure
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
43

g
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
44

International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
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International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
46

5. Spectral function
Wake function
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
47

RF parameters
Phase advance / cell
Iris thickness
Bunch population
Q (In / Out)
R’ (In / Out) vg/c (In / Out)
Eacc max (L./UnL.)
P in
∆T max sur
E max sur
S c max
RF-beam efficiency
Unit
Deg.
mm
10 9
-
MΩ/m
%
MV/m
MW o K
MV/m
W/μm 2
%
DDS_A
120
4/1.47
4.2
5020 / 6534
51 / 118
2.07 / 1.0
105 / 132
71
51
220
6.75
23.5
DDS_HPA42 DDS_HPA32
150 150
3.2/2.8
4.2
6931/7045
72.4/102.4
3.2/2.8
3.2
6931/7045
72.4/102.4
2.1 / 0.45
93 .3/ 143
68.2
51
234
5.9
29
2.1 / 0.45
90/ 138
63.6
48
225
5.5
23.3
48
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland

 Better dipole damping
 Low surface fields
 Less in power required (low beam loading)
 Need to improve dipole spread (at present 1.7 GHz)
 Need to improve rf-beam-efficiency
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
49

6.1 Enhanced damping :Eight manifolds
Four regular and four additional manifolds
Significant coupling
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
50

Cell parameters a = 4.3 mm t = 2.6 mm
R c
M r
M c
= 9.0 mm
= 2.0 mm
= 15.1 mm
Fundamental mode properties
Q=7080
R’/Q=10.356 (kΩ/m) v g
=3.3 (%c)
E s
/E acc
=2.22
H s
/E acc
=4.3 (mA/m)
S c
/E acc
=5.45 x 10 -4 (W/μm 2 /Eacc 2 ) f syn
=16.1 GHz
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
51

Iris radius = 4. 0 mm
Iris thickness = 4.0 mm
Sic
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
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• Next step after CLIC_DDS_A is to provide for the “whole” structure which includes HOM couplers
• Studies are in a very preliminary phase
• The fundamental problem is to match the coupler in the whole first dipole band which goes roughly from 15.9GHz to 18GHz
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
53

Polarization 1
Freq=15.9GHz
Feeding
Polarization 2
We do not care about it: it is well above cutoff
A first qualitative result
Feeding
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
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1.
V. F. Khan, et. al , A High Phase Advance Damped And Detuned Structure For The
Main Linacs Of CLIC, LINAC10, 2010.
2.
V. F. Khan, et. al , Recent Progress On A Manifold Damped And Detuned Structure
For CLIC, IPAC10, 2010.
3.
R. M. Jones, et. al , Influence Of Fabrication Errors On Wakefunction Suppression
In NC X-Band Accelerating Structures For Linear Colliders, NJP, 11 , 033013,
2009.
4.
V. F. Khan and R.M. Jones, Investigation of An Alternate Means Of wakefield
Suppression In The Main Linacs Of CLIC, PAC09, 2009.
5.
R. M. Jones, Wakefield Suppression For High Gradient Lineacs For Lepton Linear
Colliders, PRST-AB, 12 , 104801, 2009.
6.
V. F. Khan and R.M. Jones, An Alternate Design For CLIC Main Linac Wakefield
Suppression, XB08, 2008.
7.
V. F. Khan and R.M. Jones, Beam Dynamics And Wakefield Simulations For The
CLIC Main Linacs, LINAC08, 2008.
8.
V. F. Khan and R.M. Jones, Wakefield Suppression In CLIC Main Linacs,
EPAC08, 2008.
9.
R. M. Jones, et. al , Wakefield Suppression In A Pair of X-Band Linear Colliders,
PRST-AB, 9 , 102001, 2006.
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
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• CLIC_DDS_A : A 2π/3 phase advacne single structure, is being fabricated (G. Riddone) and will be tested for high power performance ar CERN in 2011.
• CLIC_DDS_HPA : Is being studied for further optimisation by implementing additional manifolds and/or insertion of lossy material
SiC.
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
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•
I am pleased to acknowledge a strong and fruitful collaboration between many colleagues and in particular, from those at CERN, University of Manchester, Cockcroft
Inst., SLAC and KEK.
•
Several at CERN within, the CLIC programme, have made critical contributions: W. Wuensch, A. Grudiev, I. Syrachev,
R. Zennaro, G. Riddone (CERN).
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
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International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
58

∆t
∆a
∆b
International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
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International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
60

International Workshop on Linear Colliders, 18-22 Oct 2010, CERN, Switzerland
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