technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

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Riezlern/Austria, March 2008

Radiation-Electron-Beam-Interaction: New Perspectives for Future Light Sources Thomas Weis Fakultät für Physik / DELTA

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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Zentrum für Synchrotronstrahlung DELTA

technische universität dortmund

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Content: • General Properties of Synchrotron Radiation • 3rd Generation Light Sources (where we are today !) • Insertion Devices / Undulators • Coherent Radiation / Towards New frontiers • Radiation-Electron-Beam Interaction • Free-Electron-Lasers / New Concepts • Summary Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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Zentrum für Synchrotronstrahlung DELTA

technische universität dortmund

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Dipole Radiation

Undulator Radiation Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

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Radiation Spectrum 700

600

500

nm 400

visible light

frequency

v [Hz]

short wave AM

FM TV

micro waves

light

long wave

radar

104 105 106 107 108 109 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023

infrared UV X-ray IR Synchrotron Radiation

γ−ray

104 103 102 101 100 10-1 10-2 10-3 10-4 10-5 10-6 10-7 10-8 10-9 10-10 10-11 10-12 10-13 10-14

wavelength

c m 8 λ = and c = 3 ⋅ 10 v s

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

λ [m]

object size ~ wavelength 4

Zentrum für Synchrotronstrahlung DELTA

technische universität dortmund

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Intensity

An intense hard X-ray beam entering air through a thin foil

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

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v = 0.3 c

Angular Distribution of Synchrotron Radiation v = 0.9 c θ∼

1

γ

Example: E = 3 GeV γ = 6000 θ ∼ 1/6 mrad

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

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a very tiny, extremely well characterised and intense beam dipole

typical transverse beam size

10 - 100 µm mirror CCD-camera

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

10 - 500 µm 7

technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

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Power Density of Synchrotron Radiation 1 m²

Sun Psol = 63 MW/m

2

Ppeak = 8000 MW/m 2 Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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Zentrum für Synchrotronstrahlung DELTA

technische universität dortmund

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3rd generation light source

Courtesy: ESRF

Courtesy: ESRF Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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Zentrum für Synchrotronstrahlung DELTA

technische universität dortmund

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„European Synchrotron Radiation Facility“ (ESRF) in Grenoble

Beam Energy = 6 GeV Circumference = 840 m

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

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wiggler / undulators

general properties of synchrotron radiation

dipoles

small divergence polarised exactly calculable pulsed ~ps time

high intensity broad / continuous spectrum Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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Zentrum für Synchrotronstrahlung DELTA

technische universität dortmund

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where we are today in terms of brilliance

3rd Generation Light Sources:

reliable research tool

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

photons/s/mA/mm2/mrad2/0.1%BW

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Example: DELTA/Dortmund

Undulator Radiation Ec

Ec

D. Schirmer et al., Proc. 2004 EPAC (2004) 2296 Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

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Undulators and Enhanced Brilliance

λu

period length

S N S N

beam N S N S

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

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x s

λu2 B x(t ) ~ cos(ωu t ) γ in laboratory frame: horizontal periodicity follows undulator periodicity Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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Zentrum für Synchrotronstrahlung DELTA

technische universität dortmund

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Spontaneous Emission from Undulators

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

Courtesy: DESY

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technische universität dortmund

Zentrum für Synchrotronstrahlung DELTA

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1. Apply a Lorentz-transformation: Travel with the electrons at the mean longitudinal velocity: 2 λu B * x (t ) ~ cos(γωu t * )

γ

horizontal periodicity enhanced by factor γ.

2. Oscillating electrons emit radiation (Hertz-Dipol) perpendicular to axis of oscillation at this specific angular frequency

γωu

3. Transformation to the laboratory frame (observer looking towards the electron beam again enhances the radiation frequency by factor of γ. 2

γ ωu

Thomas Weis / Riezlern 2008 / Beam Laser Interaction

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Zentrum für Synchrotronstrahlung DELTA

technische universität dortmund

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Undulator Radiation: Resonance Condition The emitted radiation from successive undulator periods adds up coherently !! Examples: for K