TESLA 500 GeV parameters TESLA 800 GeV parameters

superconducting solid Nb cavities

E(acc) ~ 25 MV/m, T=2K

Long RF pulses ( ~ 1 ms)

low RF peak power (200 kW/m)

long bunch train with large interbunch spacing

Low RF frequency (1.3 GHz)

small wakefields

The TESLA acceleration structures:

Overall design compatible with E(cms) = 91 .... 800 GeV

baseline design and parameters for 500 GeV

module geometry module length V(acc) Fill factor RF/modul e
9−cell structure 1.04 23.40 78.00% 219
4x7 superstructure 3.23 22.00 89.00% 675

TH 1801 multi beam Klystron

  1. High power (10 MW peak)

  2. Low voltage (117 kV)

  3. High efficiency (65 %)

  4. Long pulse (1.5 ms)

Is now being used at the TTF LINAC

Problem: Cavity deform under the Lorentz force at high gradient

  1. Cavity changes its shape

  2. cavity is detuned

first successful test on cavity C45 at 20 MV/m


active compensation using piezo−crystal

l = 39mm V(max)= 150 V f(max) = 500 Hz

piezo actuator Since observation of first lasing:

Smaller wavelength

better reproducibility

higher brilliance

What is the origin of the symmetry breaking in the electroweak sector

Which mechanism gives mass to fundamental particles?

  1. Can the four fundamental forces of nature, the electromagnetic, the weak, the strong force and gravity, be unified in a comprehensive theory?

  2. Where do quark and lepton flavour come from?

why 3 generations? CP violation? Mixing

Papers: Once "signals" are found:

Determine mass and width

measure quantum numbers J PC

determine the couplings to fermions (mass)

measure Higgs self

the potential

separate SM Higgs from SUSY Higgs or other models

Alternative channel: WW fusion

Main interest: determine the width of the Higgs Boson:

Method 120 GeV 160 GeV WW 0.061 0.140

Polarisation of lepton beam is very

γγ 0.230

important to turn on / off the SM backgrounds

Have to determine the quantum numbers of the Higgs particle

Spin J

Study the nature of the candidate (SM, MSSM, ...)

Threshold behaviour if light Higgs is not found: return to lower energies as a first step!

redo the indirect Higgs "limits"

using GIGA Z:

get much more stringent information

if there is an inconsistency somewhere,

it will show up here

Finding the Higgs Boson

Measuring total width, couplings

Measure the quantum numbers

explore the Higgs potential is there a structure below the known one

new heavy Z

Leptoquarks? exotic spin 2 exchange particles? ...


best studied in the reaction: e e

f f

key to Supersymmetry: discovery spectroscopy to select the correct model

in "all" models: expect at least some of the SUSY partners at few 100 GeV ("no loose theorem",

nearly model


spectacular signals for SUSY partners if in the kinematic reach at LC

precision measurements allow the extrapolation to high energies with good precision: learn about the high energy behaviour use this to distinguish models Mass reach of LHC larger

precision reach of LC better (if within mass reach) access to anything beyond the mass essentially only at LC

separation of different SUSY particles difficult at LHC

Remark: polarisation of lepton beams is an important ingredient to determine the sparticle properties

polarised electron

using electrons from TESLA

use low intensity electron bunches in between the HEP bunches: no interference to HEP running



reach in x

TPC: Time Projection Chamber

large gasfilled system little material true 3−D reconstruction possible large granularity

calorimeter at E>500 GeV will be very important TESLA concept:

a high precision, "tracking" calorimeter


W absorbers, SI sensors (1x1 cm pad)

a linear collider with E= 500 to 800 GeV offers a rich physics program

EWSB: major insights expected Higgs precision measurements SUSY (or similar) precision study model independent search for alternative scenarios

many precision measurements to significantly extend our present knowledge electroweak precision measurements W mass measurement top mass and properties QCD physics ....

a linear collider will also search for the totally unexpected substructure? completely new physics: extra dimensions? ...

electron beam is sent through undulator coherent emission of laser light:

First lasing at <100 nm observed 02

First lasing at <100 nm observed 02

Smaller wavelength tunable wavelength

Brilliance of different sources:


expected Photon Flux for XFEL


atomic physics, interaction with matter, plasmaphysics

intensity, short pulses

femtosecond chemistry, structural biology

short pulses

spectroscopy: dynamics of complex systems, holography on a atomic scale

coherent lightsource

A linear electron positron collider has an exciting physics program:

Physics at the free electron laser

Under construction: Tesla Test Facility Phase TTF II

Goal: −demonstrate the superconducting technology (TTF I, done) − demonstrate the SASE principle in the <100nm range (done) −gain experience operating a superconducting linac and FEL −>2003: user facility for Roentgenlaser