Tor Raubenheimer

Linear Collider Parameters

International Linear Collider School

May 21st, 2006

Outline

• Luminosity and beam parameters– Introduction– Luminosity expressions– IP parameters

• Beamstrahlung• Disruption• Spot size limitations

– Particle sources– Emittance generation

• Damping rings, bunch compression, and Linac emittance limits– Final focusing system

– RF system parameters and efficiency to be covered by Chris Adolphsen

Schematic of the ILC

SLC: The 1st Linear Collider

Built to study the Z0 and demonstrate linear colliderfeasibility

Energy = 92 GeV

Luminosity = 3e30

Had all the featuresof a 2nd gen. LCexcept both e+and e- shared thesame linac

Much more than a 10% prototype

SLC luminosity:Many Lessons Learned

Luminosity versus SLC

Enhancement FactorsUNITS SLC GLC/NLC TESLA NLC/SLC TESLA/SLC NLC/SLC TESLA/SLC

E_cm GeV 92 500 500 5.43 5.43f_rep Hz 120 120 5n_b 1 192 2820N 4.10E+10 7.50E+09 2.00E+10 0.18 0.49H_d 2 1.43 2.1 0.72 1.05

sqrt(e+ x e-)Inj_Inv_Emit_x 10^-8 m-rad 3834.1 300 800 0.08 0.21 3.57 2.19Inj_Inv_Emit_y 10^-8 m-rad 259.8 2 2 0.01 0.01 11.40 11.40

IP_Inv_Emit_x 10^-8 m-rad 6144.3 360 1000IP_Inv_Emit_y 10^-8 m-rad 1715.2 4 3Dilution-X 1.60 1.20 1.25 0.75 0.78 1.16 1.13Dilution-Y 6.6 2.00 1.50 0.30 0.23 1.82 2.10BetaX mm 3.3 8 15 2.42 4.55 0.64 0.47BetaY mm 2.6 0.11 0.4 0.04 0.15 4.86 2.55IP Divergence-x urad 454.8 30.3 36.9IP Divergence-y urad 270.7 27.3 12.4sig_x nm 1500.8 242.6 553.7 1.62E-01 3.69E-01 3.77E-01 8.60E-01sig_y nm 703.8 3.0 5.0 4.26E-03 7.04E-03 9.93E-03 1.64E-02SigX*SigY nm^2 1056321.0 727.6 2742.3 6.89E-04 2.60E-03

P_b MW 0.036 6.921 11.294 190.88 311.51I uA 0.788 27.683 45.176 35.12 57.32I*N A 32315.5 207619.2 903528.0 6.42 27.96

L 3.04E+30 2.03E+34 3.44E+34 6668.90 11308.32CrossSection nb 30 "Free"=Energy, Beam Power, Q/bunch 34.92 151.95Event Rate Z/hr 328 Disruption 0.72 1.05

Damping Ring 40.75 24.95Emittance Preservation 2.10 2.38

Aggressive FF 3.12 1.20Total 6668.90 11308.32

Experimental Basis for the ILC Design

Linac rf system

BDS & IR

DampingRings

e+ / e- Sources

Bunch Compression

SLC, E-158

SLC and(ATF2 in the future)

SLC, FFTB, ASSET, E-158

ATF, 3rd Gen Light Sources, SLC

Preservation

TESLA Test Facility (SMTF & STF in the future)

SLC and FEL’s

Luminosity: Aiming for 2x1034

Collider luminosity (cm-2 s-1) isapproximately given by

where:

nb = bunches / trainN = particles per bunchfrep = repetition frequencyA = beam cross-section at IPHD = beam-beam enhancement factor

For a Gaussian beam distributionwhere x = sqrt(x1

2 + x22):

Drepb H

A

fNnL

2

Dyx

repb HfNn

L

2

2

Luminosity

• frep * nb tends to be low in a linear collider

• Fortunately the beam-beam tune shift limit is much looser in a linear collider than a storage rings achieve luminosity with spot size and bunch charge– Small spots mean small emittances and small betas:x = sqrt(x x)

Dyx

repb HfNn

L

2

2

L frep [Hz] nb N [1010] x [mm] y [mm]

ILC 2x1034 5 3000 2 0.5 0.005

SLC 2x1030 120 1 4 1.5 0.5

LEP2 5x1031 10,000 8 30 240 4

PEP-II 1x1034 140,000 1700 6 155 4

Interjection – Phase Space

Beta function characterize optics

Emittance is phase space volume of the beam – optics analogyis the wavelength

Tilt is parameterized with

Beam size: ( Divergence: ()1/2

Squeeze on beam size increase angular divergence

Beam emittance is not conserved during acceleration normalized emittance should be

Linear Collider Luminosity

• Convert luminosity expression using beam power– Pbeam = Ecms * eN * nb * frep

– Required to have large beam powers

• Further constrained by IP effects– Beamstrahlung – synchrotron radiation due to strong beam fields– Disruption – beam distortion due to strong beam fields at the IP

– Hourglass – ≥ z

• For flat beams (x >> y)where ~ N2/x

2z

Dyxcms

beam HN

E

PL

4

Dy

beam HPL

Main Linac RF System

(8 Cavities per Cryomodule)

~90% eff.

~95% eff.

~65% eff.

Cavity losses are very small butcryo-system efficiency ~0.2% small losses have impact

Beam Power Issues

• Beam power depends upon linac design, operating limitations, and collider AC power consumption limitations– Typical AC beam efficiencies are ~20% (inc. cooling) 11 MW beam power implies ~100 MW AC power

– In practice there are many other requirements• ILC site power consumption is closer to 200 ~ 250 MW

– SC cavities dissipatelittle power but still needto be filled 65% eff.

– Ac rf power efficiency depends on technologybut is typically ~50%plus ~ 10% for overhead

• Covered by C. Adolphsen

0 500 1000 1500 2000 250020

10

0

10

20

30

40generatorvoltage

cavityvoltage

beaminducedvoltage

beam on

RF on

Beam Parameters

• Requirements:– High luminosity – set by physics needs

– Low backgrounds (small IP effects)

– Forced to high beam power and small vertical spots

• Details of technology determine other limitations– Rf cavities and power sources 10 mA beam current

– Damping rings beam emittances and number of bunches

– Bunch compressors IP bunch length

– Cryogenic systems duty cycle

– Extensive cost optimization is required to balance systems

• Linear collider will push many technological and beam-physics limits – Need to have operational flexibility to overcome unexpected problems

ILC Parameters

nom low N lrg Y low P High L

N 1010 2 1 2 2 2

nb 2820 5640 2820 1330 2820

x,y mm, nm 9.6, 40 10,30 12,80 10,35 10,30

x,y cm, mm 2, 0.4 1.2, 0.2 1, 0.4 1, 0.2 1, 0.2

x,y nm 543, 5.7 495, 3.5 495, 8 452, 3.8 452, 3.5

Dy 18.5 10 28.6 27 22

BS % 2.2 1.8 2.4 5.7 7

z mm 300 150 500 200 150

Pbeam MW 11 11 11 5.3 11

Parameter range established to allow for operational optimization

IP Parameters

• IP parameters determine basic beam structure– Charge per bunch– Beam power– IP spot sizes– All parameters are linked

Linear Collider Parameters

• Model for linear collider design!

Bob Palmer1990

Beam-Beam Tune Shifts

• Fields from charge particles focus (or defocus) each other as they pass through each other in IP– Effect is known as the beam-beam tune shift in a storage ring x,y and

is typically limited to ~ 0.05 to prevent the beam spot sizes from increasing as the beam circulates

• In ILC, the ‘ring tune shift’ is ~2 (thin lens calculation)• Ideally in single-pass collider the tune-shift is not a limitation

– In practice it is still a limit but is much looser – The analogous effect is referred to as the disruption in an LC

)(2 ,

,,

yxyx

yxeyx

Nr

IP Beam Fields (1)

• Fields from charge particles focus (or defocus) each other as they pass through each other in IP

• Fields from relativistic beam are radial – spread as 1/:

arr

E

ara

rE

r

r

2

2

0

20

a

v ~ c linear charge density =

IP Beam Fields (2)

• Fields in Gaussian beams peak ~ and then decay as 1/r (in a roundGaussian beam)

• Peak field

• Beam fields are very strong– Linear colliders are designed with ‘flat’ beams to minimize the IP fields for a

given luminosity• Luminosity is inversely proportional to cross-sectional area• Fields are inversely proportional to surface area

– Flat beams are naturally generated in damping rings and thus this is an ‘easy’ optimization

• With asymmetric Gaussian beams:

zrr

eNE

02ˆ

zxy

eNE

04ˆ

IP Beam Fields (3)

• F = e(Er + cB)– E and B cancel at as 1/2 in co-propagating

– E and B add in counter-propagating beams F ~ 2eEr

• Fields are extremely strong at IP ~ few V / Angstrom or kT [kilo-Tesla]

• Main effects: beam disruption and synchrotron radiation

• Focusing at IP is given by dF / dr normalize by charge and mass K [m-2]

• Now:

• Finally with asymmetric Gaussian beams: a2 2x,y(x + y)

2

4

a

rK e

0 Kxx

IP Beam Fields

• Two main effects:– Beamstrahlung – Synchrotron radiation of particles in the strong

fields of the opposing beam; many % of the beam energy can be radiated

• Pair production – Intense fields can convert beamstrahlung photons into e+/e- pairs

– Disruption – fields of the opposing beam will distort the beam during the collision

• Pinch effect luminosity enhancement where mutual focusing of the oppositely charged beams increases density in collision

• Beam-beam deflections small offsets between the beam are amplified into large angular kicks which can be measures and used to stabilize the collision

• Single bunch kink when disruption is large enough, end up with a two-stream instability which can reduce luminosity

Beamstrahlung

• The IP fields cause synchrotron radiation– Generates potential backgrounds– Degrades the luminosity spectrum

• Effect is described with three parameters:– Average energy loss: – Number of photons: n

– Quantum parameter: Y

– Simplistically, n describes the spectrum close to the center-of-mass energy while describes the tails

Simple Beamstrahlung

• Beam particles radiate synchrotron radiation in strong fields

where

• For nominal ILC parameters at 250 GeV and using the peak B field ~60 GeV radiated in collision or 25% of energy

– Need to do the calculation properly averaging over the beam but scaling is clear

USR ~ 2 z N2 / x2

1-0

0

3-5z2

4

GeV Tesla m 335.3 ;1

mGeV 1085.8 ;c

2t t;

2

BB

B

CEcC

U SR

Quantum Effects

• Assumed classical synchrotron radiation formulation but at high-energy and high-fields quantum effects can be important– The critical photon energy is:

– Effects are parameterized with Upsilon:

TeV linear collider designs operate withY << 1 but, above 1 ~ 2 TeV, upsilonis usually chosen to be greater 1

GTesla 4.4 where3

2 c

c

c BB

B

E

323

~2

3 c

c

Beamstrahlung Formula

• Approximate formulas can be written which describe the process over the usual range of LC parameters

• See: P. Chen, “Differential Luminosity under Multi-Photon Beamstrahlung”, Phys. Rev. D, 46:

1186 (1992).

K. Yokoya, P. Chen, “Beam-beam phenomena in linear colliders,” Lecture Notes Physics, 400: 415 (1992).

P. Chen, “Disruption effects from the collision of quasi-flat beams,” PAC 93.

23/2

2

B

3/2

2

5.11

1

4

5

1

12n

)(6

5

3

2

e

z

yx

e

yxz

ec NrNr

E

Pair Production (1)

• The beamstrahlung photons can create e+/e- pairs– Incoherent pair production – arises from photons scattering off of

beam particles• Multiple channels but typically relatively few pairs ~105

– Coherent pair production – arises from photon scattering off collective fields of the beam

• With Y ~ 1, as many pairs as beam particles

Pair Production (2)

• Pairs are a significant source of background– Relatively low energy

particles are given large transverse deflections by the beam fields

– Can be partly controlled with strong solenoidal field at the IP but need to be careful with detector design to constrain the particles and secondary interactions

Disruption (1)

• Strong fields will distort the opposing beam • Normalized beam-beam focusing force at the IP:

• Disruption parameter defined using thin lens approximation and comparing focal to bunch length

• Assume a rectangular distribution number of oscillations in opposing bunch:

)(

2

,,

yxyx

eyx

rK

0 Kxx

)(

2

,,,

yxyx

ze

yx

zyx

Nr

fD

23.1D

n

Luminosity Enhancement

• Mutual focusing of oppositely charged beams can increase

the collision density– HD is small

~1.5 with flatbeams

• Increased Dy

makes lumisensitive tooffsets From Yokoya & Chen

Dy

Luminosity with Offsets

• Disruption forces help stabilize the collisions tooffsets for lowDy but thesingle-bunchkink instabilityreducesluminosityat high Dy > 15

y / y

HD

= L

/L0

Luminosity Enhancement

• Many simulations have been written to model IP environment:– CAIN – Yokoya and Chen– GuineaPig – Shulte

• An empirical expression was fit to simulation results

• Depends on disruption and weakly on depth of focus (hour-glass effect) – Expression is valid over typical LC parameters– Needs to supported with detailed simulations

3, ,1/ 4

, , ,3,

0.81 ln 1 2ln

1x y x y

Dx y x y x yx y z

DH D D

D

Hourglass Effect

• Hourglass limits y ~ z

200 400 600 800 1000

11034

21034

31034

41034

51034

300z m m

100z m m

500 mm

700 mm

900 mm

( )y m m

2 1( )L cm s

From Nick Walker for TESLA

Single Bunch Kink (1)

• Single bunch kink is a two-stream instability– Small offsets are amplified by very strong beam-beam forces

• Potential limitation at high disruption parameters– Why high disruption?

– Luminosity expression can be re-written in terms of Dy

– If there is a practical limit on the maximum disruption luminosity can be increased by shortening the bunch

– Hard to avoid larger beamstrahlung

Dz

y

cms

beam HD

E

PL

3

22

zyyB D

)(

2

,,,

yxyx

ze

yx

zyx

Nr

fD

Single Bunch Kink (2)

Single bunch kink due to 1% initial offset between beams

Dy = 12

Dy = 24

Single Bunch Kink Movie

ILC Parameters

nom low N lrg Y low P High L

N 1010 2 1 2 2 2

nb 2820 5640 2820 1330 2820

x,y mm, nm 9.6, 40 10,30 12,80 10,35 10,30

x,y cm, mm 2, 0.4 1.2, 0.2 1, 0.4 1, 0.2 1, 0.2

x,y nm 543, 5.7 495, 3.5 495, 8 452, 3.8 452, 3.5

Dy 18.5 10 28.6 27 22

BS % 2.2 1.8 2.4 5.7 7

z mm 300 150 500 200 150

Pbeam MW 11 11 11 5.3 11

Parameter range established to allow for operational optimization

Schematic of the ILC

Polarized Electron Source

• Polarized electron beam generated from a polarized laser on a strained GaAs photocathode

• Technology is robust– Demonstrated for years on SLC and E-158 at SLAC– Laser system has new requirements but is not thought to be a significant

technical limitation

• Options for new technology in the form of polarized rf guns– Requires more robust photocathode material– Gains in operational simplicity but not large cost savings UNLESS the rf

gun can replace the damping rings– Damping rings have multiple functions

• Damp incoming phase space• Provide a stable platform and damping incoming transients• Allow for feed-forward to pre-set linac systems

ILC Electron Source

Laser

120 keV 12 MeV 71 MeV

BuncherSHB |---- RT Pre-Accelerator----|12 MeV / m

Klystron 10 MW Spare Klystron 10 MW

Tune-up dump(diagnostics section)

Diagnostics

Gun

Gun

Laser

Polarized Photo-cathodes

Polarized Photo-Cathode R&D

• Strained superlattices are yields ~90% polarization• Further optimization possible for ILC bunch train• Develop GaN as a more robust alternate

Strained GaAs

GaAsP

Strained GaAs

GaAsP

Strained GaAs

GaAsP 30 A

40 A

GaAs Substrate

GaAs(1-x)Px Graded Layer

GaAs0.64P0.36 Buffer

Active Region

25mm

25mm

1000 A

Positron Source

• Large number of positrons required per second– 60 times more than in SLC– Pulsed damage to the target– Average heating of the target– Radiation damping to the target

• Difficult complex system

SLC e+ target Beam direction

Target and Capture Structures

ILC Positron Source

• Three options considered for ILC– Thick 4 rl WRe target with ~6 GeV e- beam

• Conventional technology but very high radiation loads– Thin Ti target with 10 MeV photon beam

• Photon beam generated by passing 150 GeV e- thru undulator• Allows for e+ polarization as well

– Thin target using Compton scattered laser beam• Requires very powerful laser systems but would have benefits of

independence from e- beam and possible polarization

• Capture systems are the same in all cases– Chose undulator-based source as baseline– Many advantages – only problem is that it couples e+ source to the

electron beam and constrains timing systems and beam operations

Undulator-Based Positrons

• 200 meters of helical undulator in electron beam line• Photons impinge on 0.5 rl Ti target• Captured in normal conducting structures

– High radiation environment with large beam losses does not work for superconducting structures

• Not much head-room on e+ production rates

e- sourcee-

DR

e- Dump Photon Dump

e+

DRAuxiliary e- Source

Photon Collimators

Adiabatic Matching

Device

e+ pre-accelerator ~5GeV

150 GeV 100 GeV

HelicalUndulatorIn By-Pass

Line

PhotonTarget

250 GeV

Positron Linac

IP

Beam Delivery System

e- Target

Adiabatic Matching

Device

e- Dump

Damping Rings

• Damping rings have more accelerator physics than the rest of the collider

• Required to:1. Damp beam emittances and incoming transients

2. Provide a stable platform for downstream systems

3. Have excellent availability ~99% (best of 3rd generation SRS)

• Mixed experience with SLC damping rings:– Referred to as the “The source of all Evil”– Collective instabilities; Dynamic aperture; Stability

• Damping ring designs based on KEK ATF, 3rd generation SRS, and high luminosity factories– Experimental results provide confidence in design

KEK ATF Damping Ring

World’s lowest emittance beam:y = 4 pm-rad

below X-band LC requirements

Used to verify X-bandDR concepts

Detailed measurementsof emittance tuning, lattice properties, IBS, ions, collective effects,and instrumentation

1.3 GeV Damping Ring and S-band linacCommissioning started in 1997

• Probably world’s largest linear collider test facility

Damping Ring Emittances (1)

• See M. Sand, “Physics of Electron Storage Rings,” SLAC-121 (1972).

• Two competing processes: radiation damping and quantum excitation

• Radiation damping:– Longitudinal phase space

• Higher energy particles radiate more energy than low energy particles in the bends

– Transverse phase space

• Radiation is emitted in a narrow cone centered on the instantaneous direction of motion

– Transverse momentum is radiated away

• Energy is restored by the RF cavities longitudinally

• Combined effect of radiation and RF is a loss in transverse momentum

Damping Ring Emittances (2)

• Quantum excitation– Radiation is emitted in discrete quanta– Number and energy distribution etc. of photons obey

statistical laws– Radiation process can be modeled as a series of “kicks” that

excite longitudinal and transverse oscillations

NominalTrajectory E = 0

Low E Trajectory

Start to oscillate about nominal trajectory

Damping Ring Emittances (3)

• Quantum excitation occurs in the horizontal plane • Two effects determine the vertical emittance:

– Opening angle of the SR – typically limits at about 10% of design emittance

– Alignment errors which couple the horizontal to the vertical • Vertical bending due to orbit errors• Skew quadrupole fields due to quadrupole rotations or vertical

sextupole misalignments• Tolerances are very tight – frequently a few microns

• Combined effect of radiation damping and excitation:

tt

t2

equ2

inj e1ed

d inj = injected emittance

equ = equilibrium emittance

= radiation damping time

Issues in the Damping Rings

• Emittance tuning and error correction– Orbit correction and component stabilization

• Injection/extraction of individual bunches– Kicker rise/fall time – very large rings to store 3000 bunches

• Dynamic aperture– Long wigglers needed if the ring is too big

• Single-bunch intensity– Tune shift by self-Coulomb force (space charge)

• Instabilities (mainly average current)– Electron cloud instability

– Fast ion instability

– Classical collective instabilities

• Rings operate in a new regime with fast damping and very small beam emittances

Bunch Compressors

• Bunch lengths in damping rings are ~1cm– Seen that for high luminosity, would like short bunches at the IP

• Compress bunches in magnetic bunch compressors after the damping rings– Three problems:

• Magnetic bunch compressors operate by bending the beam synchrotron radiation can dilute the beam emittances

– Normalized emittance growth scales as 6 in transport line• Longitudinal phase space is conserved shortening the bunch length

will increase the energy spread– Large energy spread in the linacs makes preserving the beam

emittance more difficult ~ (E/E)2

• Longitudinal nonlinearities make compressing by more than 10~20x difficult in any single stage

Bunch CompressorsMagnetic bunch compression

z

z

z

RF AcceleratingVoltage

Path Length-EnergyDependent Beamline

V = V0sin()

z0

z

z = R56

Under-compression

Over-compression

ILC BC Solution

• Want capability of compressing from 6mm 150 mm• Factor of 40 too large for a simple single-stage system

– Dual stage system:• Compress just after damping ring at 5 GeV by ~6x• Compress again at ~15 GeV point by another factor of ~8x• Provides large operating range while limiting the energy spread

in the linacs less emittance dilution than in a single-stage

• Bunch compressor system also includes:– Transverse and longitudinal collimation– Spin rotation– Skew correction to correct errors from damping ring or in the spin

rotation system– Extensive diagnostics before launching the beam into the linac

Linac Beam Dynamics

• Main issues in the linac are:– Short-range wakefields– Dispersive emittance dilutions

• Superconducting linac has relatively loose tolerances for wakefield dilutions– Cavity alignment at the 300 mm level

• Need to be careful on alignment at the low energy ends of the linac due to the dispersive dilutions– Must align the quadrupoles at the 25 mm level to avoid dispersive

dilutions: ~ (E/E)2

– Requires beam-based alignment techniques

Linac Parameter Trades

Damping Ring(sources)

IR (IP)Beam extraction

Linac(relaxed within limits)

From Nick Walker, Snowmass 2005

Beam Delivery System

• Requirements:– Focus beams down to very small spot sizes– Collect out-going disrupted beam and transport to the dump– Collimate the incoming beams to limit beam halo– Provide diagnostics and optimize the system and determine the

luminosity spectrum for the detector– Switch between IPs

Beam Delivery System Layout

2mrad collim & FF

20mrad collim & FF

• BDS designed up to 1TeV w. fixed geometry

• FF with local chrom.corr.-spoilers survivable up to 2 bunches

• E-coll after -coll for clean collimation

Collimation System and MPS

• Collimation system must remove beam tails• Extremely dense beams are very difficult to collimate and

stop – Machine Protection System is a challenge• Collimation system becomes long and difficult with tight

tolerances if the beam size is increased sufficiently to prevent damage

IP Switchyard

to tune-up dump to IPs

MPS betatron collimators

skew correction

4-wire 2D diagnostics

Energy diag. chicane

kicker (comb w. bends), septum

polarimeter chicane

collim.

High bandwidth horiz. bend.sys.

EBSY

• Recent modifications:– sacrificial MPS betatron collimation at entry– septum & tune-up line is being redesigned, to

be released soon

1mm beam at laser wires with DR emitt. y=2e-8m at 1TeV

610 10 m0E 500 GeVbeam

x 12.9 %0

x

x

ISR in 11mrad bend:

E-collim.

tapered spoilers

IR Design (1)

• 20(14)mrad IR– Self shielded compact quads

successfully tested – Focus on 14mrad alternative to

push the technology

• ILC crab cavity:– collaboration of Fermilab, UK

(Daresbury, et al), SLAC. – Based on 3.9GHz deflecting

cavity designed at Fermilab. Design is being verified and preparing for production

Omega3P Mesh

3.9 GHz deflecting cavity, early 13 & 3 cell models and recent 9cell design

Fermilab

BNL

IR (2)

• Small and large crossing angle designs

• Pairs induced background similar in both cases

• Losses in extraction & background harder in 2mradbut 2 mrad easier for detector

80

60

40

20

0

Bea

mCal

Ene

rgy

(TeV

)

3.02.52.01.51.00.50.0

Beampipe Radius (cm)

2 mrad 20 mrad 14 mrad 14 mrad + DI D 14 mrad + Anti-DI D

Pairs induced backgriund in SiD

Parameter Tables

• Most of the parameter relations can be put into an Excel spreadsheet– Makes it simple to compare different scenarios

Primary parameters and analytic calculations

TESLA USSC 31 MV/m 36 MV/m 42 MV/m Nominal Low Q Large Y Low P High Rate High LumEcms 500 500 500 500 500 500 500 500 500 500 500gamma 4.89E+05 4.89E+05 4.89E+05 4.89E+05 4.89E+05 4.89E+05 4.89E+05 4.89E+05 4.89E+05 4.89E+05 4.89E+05N 2.00E+10 2.00E+10 2.00E+10 2.00E+10 2.00E+10 2.00E+10 1.00E+10 2.00E+10 2.00E+10 2.00E+10 2.00E+10nb 2820 2820 2820 2820 2820 2820 5640 2820 1330 1410 2820Tsep [ns] 336.9 336.9 295.4 295.4 269.2 295.4 147.7 295.4 443.1 295.4 295.4Buchets @ 1.3 GHz 438 438 384 384 350 384 192 384 576 384 384Iave 0.0095 0.0095 0.0108 0.0108 0.0119 0.0108 0.0108 0.0108 0.0072 0.0108 0.0108Gradient 23.40 28.00 31.00 36.00 42.00 31.00 31.00 31.00 31.00 31.00 31.00Cavities / 10 MW klys 36.00 30.00 24.00 20.00 16.00 24.00 24.00 24.00 24.00 24.00 24.00Q0 1.00E+10 1.00E+10 1.00E+10 1.00E+10 1.00E+10 1.00E+10 1.00E+10 1.00E+10 1.00E+10 1.00E+10 1.00E+10Qext 2.50E+06 2.99E+06 2.90E+06 3.37E+06 3.59E+06 2.90E+06 2.90E+06 2.90E+06 4.36E+06 2.90E+06 2.90E+06Tfill (us) 420.0 502.7 487.9 566.6 602.5 487.9 487.9 487.9 731.9 487.9 487.9Trf (ms) 1.37 1.45 1.32 1.40 1.36 1.32 1.32 1.32 1.32 0.90 1.32f 5 5 5 5 5 5 5 5 5 10 5Linac overhead 0 5% 5% 5% 5% 5% 5% 5% 5% 5% 5%Pb [W] 1.13E+07 1.13E+07 1.13E+07 1.13E+07 1.13E+07 1.13E+07 1.13E+07 1.13E+07 5.33E+06 1.13E+07 1.13E+07Pac (linacs) [W] 9.40E+07 1.05E+08 1.07E+08 1.15E+08 1.27E+08 1.07E+08 1.07E+08 1.07E+08 1.07E+08 1.44E+08 1.07E+08

gamepsX 1.00E-05 9.60E-06 1.00E-05 1.00E-05 1.00E-05 1.00E-05 1.00E-05 1.00E-05 1.00E-05 1.00E-05 1.00E-05gamepsY 3.00E-08 4.00E-08 4.00E-08 4.00E-08 4.00E-08 4.00E-08 3.00E-08 8.00E-08 3.50E-08 4.00E-08 3.00E-08bx 1.50E-02 1.50E-02 2.10E-02 2.10E-02 2.10E-02 2.10E-02 1.20E-02 1.00E-02 1.00E-02 2.10E-02 1.00E-02by 4.00E-04 4.00E-04 4.00E-04 4.00E-04 4.00E-04 4.00E-04 2.00E-04 5.00E-04 2.00E-04 4.00E-04 2.00E-04sigx 5.54E-07 5.43E-07 6.55E-07 6.55E-07 6.55E-07 6.55E-07 4.95E-07 4.52E-07 4.52E-07 6.55E-07 4.52E-07sigy 5.0E-09 5.7E-09 5.7E-09 5.7E-09 5.7E-09 5.7E-09 3.5E-09 9.0E-09 3.8E-09 5.7E-09 3.5E-09sigxp 3.69E-05 3.62E-05 3.12E-05 3.12E-05 3.12E-05 3.12E-05 4.13E-05 4.52E-05 4.52E-05 3.12E-05 4.52E-05sigyp 1.24E-05 1.43E-05 1.43E-05 1.43E-05 1.43E-05 1.43E-05 1.75E-05 1.81E-05 1.89E-05 1.43E-05 1.75E-05sigz 3.00E-04 3.00E-04 3.00E-04 3.00E-04 3.00E-04 3.00E-04 1.50E-04 5.00E-04 2.00E-04 3.00E-04 1.50E-04Dx 2.26E-01 2.35E-01 1.62E-01 1.62E-01 1.62E-01 1.62E-01 7.08E-02 5.59E-01 2.26E-01 1.62E-01 1.70E-01Dy 2.53E+01 2.23E+01 1.85E+01 1.85E+01 1.85E+01 1.85E+01 1.00E+01 2.80E+01 2.70E+01 1.85E+01 2.19E+01Theta0 4.17E-04 4.25E-04 3.53E-04 3.53E-04 3.53E-04 3.53E-04 2.34E-04 5.05E-04 5.11E-04 3.53E-04 5.12E-04xp_max_out 3.19E-04 3.25E-04 2.70E-04 2.70E-04 2.70E-04 2.70E-04 1.79E-04 3.87E-04 3.91E-04 2.70E-04 3.91E-04yp_max_out 6.93E-05 7.84E-05 7.60E-05 7.60E-05 7.60E-05 7.60E-05 8.40E-05 7.72E-05 8.03E-05 7.60E-05 9.57E-05Uave 0.054 0.055 0.046 0.046 0.046 0.046 0.061 0.039 0.100 0.046 0.133delta_B 0.030 0.031 0.022 0.022 0.022 0.022 0.018 0.028 0.057 0.022 0.070P_Beamstrahlung [W] 3.35E+05 3.47E+05 2.48E+05 2.48E+05 2.48E+05 2.48E+05 2.05E+05 3.14E+05 3.06E+05 2.48E+05 7.90E+05ngamma 1.477 1.504 1.257 1.257 1.257 1.257 0.823 1.811 1.756 1.257 1.725Hdx 1.061 1.069 1.022 1.022 1.022 1.022 1.002 1.785 1.061 1.022 1.026Hdy 5.317 5.071 4.727 4.727 4.727 4.727 3.764 4.201 4.142 4.727 5.037Hd 1.80E+00 1.78E+00 1.70E+00 1.70E+00 1.70E+00 1.70E+00 1.56E+00 2.16E+00 1.65E+00 1.70E+00 1.74E+00Geo Lum 1.64E+38 1.45E+38 1.20E+38 1.20E+38 1.20E+38 1.20E+38 1.29E+38 1.10E+38 1.24E+38 1.20E+38 2.83E+38Lum. dil. 1.00E+00 1.00E+00 1.00E+00 1.00E+00 1.00E+00 1.00E+00 1.00E+00 1.00E+00 1.00E+00 1.00E+00 1.00E+00Lum. 2.94E+38 2.57E+38 2.03E+38 2.03E+38 2.03E+38 2.03E+38 2.01E+38 2.37E+38 2.05E+38 2.03E+38 4.92E+38Lum/bc 2.09E+34 1.82E+34 1.44E+34 1.44E+34 1.44E+34 1.44E+34 7.14E+33 1.68E+34 3.08E+34 1.44E+34 3.49E+34Coherent pairs/bc 7.14E-35 4.65E-34 7.71E-43 7.71E-43 7.71E-43 7.71E-43 4.29E-31 9.12E-51 3.31E-15 7.71E-43 2.21E-09Inc. pairs/bc (LL) 4.76E+04 4.15E+04 3.28E+04 3.28E+04 3.28E+04 3.28E+04 1.63E+04 3.82E+04 7.02E+04 3.28E+04 7.95E+04Inc. pairs/bc (BW) 2.70E+03 2.42E+03 1.49E+03 1.49E+03 1.49E+03 1.49E+03 2.68E+02 3.94E+03 3.98E+03 1.49E+03 3.73E+03Inc. pairs/bc (BH) 3.64E+05 3.22E+05 2.25E+05 2.25E+05 2.25E+05 2.25E+05 6.72E+04 3.94E+05 5.37E+05 2.25E+05 5.54E+05Inc. Pairs/bc (tot) 4.14E+05 3.66E+05 2.59E+05 2.59E+05 2.59E+05 2.59E+05 8.37E+04 4.37E+05 6.12E+05 2.59E+05 6.37E+05

500 GeV

Posted publicly at www-project.slac.stanford.edu/ilc/temp/ILC_parms.xls

Summary

• Basic beam parameters are determined from the luminosity requirements– ILC design then follows trying to meet those requirements

• Constrains arise from:– IP physics (luminosity, beamstrahlung, disruption, depth of focus)– Damping rings, bunch compressor and positron source– Rf acceleration – topic of Chris Adolphsen’s talk

• Details will be discussed in all the subsequent talks– Looks like a great program!– Thanks to the organizers!

• Join the ILC accelerator effort – an accelerator for the future