Bright Lights on the Horizon Future Perspectives for Nuclear Resonant Scattering of Synchrotron Radiation Ralf Röhlsberger DESY, Hamburg, Germany The Evolution of Brilliance Upgrade of Existing Sources Construction of New Sources: PETRA III and the XFEL

Evolution of Brilliance

PETRA-III Upgrade

Schedule Submission of the Technical Design Report: March 2004 Selection of the phase I beamlines: early Summer 2004 Start of beamline R&D, prototyping: mid 2004 Start of detailed beamline planning: end 2004/2005  user workshops on detailed beamline design Start of component production: 2006 Start of reconstruction: mid 2007 Installation of first beamlines: mid 2008 Start of user operation: 2009

Storage Ring Particle energy = 6 GeV Current = 100 mA (200 mA) Emittance = 1 nmrad Insertion Devices and Beamlines 13 independent undulators 1 undulator of 20 m length Technical Design Report submitted: 22 experimental stations proposed, including Nuclear Resonant Scattering Operation Number of bunches: 40 – 960 Bunch distance: 192 ns – 8 ns Top-up operation mode PETRA III - Facts and Figures

20 m undulator General Experiment Support Cryostats, high-magnetic fields, high-pressure cells, furnaces, detectors (0,1,2 - dimensional), electronics, mechanical components, lasers Revolver – type with two magnet structures: 1) optimized for 14.4 keV (fundamental) 2) optimized for 21.5 – 30 keV (third harmonics) NRS Beamline Proposed at PETRA-III

NRS from Isotopic Probe Layers using Microfocused Beams Magnetic Properties : Spin Structure and Magnetic Correlations in thin films and nanoparticles Dynamic Properties : Phonons at interfaces and in nanoparticles Nuclear resonant photon correlation spectroscopy Spot sizes well below 1  m can be reached by application of focusing mirror optics

High-Resolution Monochromators at PETRA-III Yu. V. Shvyd‘ko (2003)

Limits of Storage – Ring Based Sources Development of New Radiation Sources Beam properties reflect the equilibrium dynamics of particles in the ring, resulting from averaging over all revolutions Particles are re-cycled Design study: The Ultimate Storage Ring (USR) Radiation is generated by single bunches passing through an undulator Energy – Recovery Linear Accelerator (ERL) Sub-Picosecond Pulsed Source (SPPS) X-ray Free Electron Laser (XFEL)

X-Ray Free-Electron Lasers Synchrotron radiation –low emittance electron beam –relativistic electron energy –periodic acceleration of electron in magnetic field of an undulator –collimated radiation –tunable by electron energy & magnetic field... at x-ray wavelengths no efficient reflectors exist lasing in a ‚single-pass‘ Self-Amplified Spontaneous Emission (SASE) SASE FEL Undulator e-e-

log (power) duration, length SASE exponential growth and saturation saturation length ~ 10 L gain gain ~ 10 5 low gainexponential gain (high-gain linear regime) P(z) = P o exp(z/L gain ) non-linear

Electron bunch modulation GENESIS - simulation for TTF parameters Courtesy - Sven Reiche (UCLA) undulator entrance half-way saturation full saturation

Time structure of the XFEL radiation Single bunches. Few bunches. Long trains.

Radiation parameters Compared to 3 rd generation synchrotron radiation facilities, the gain factors are Peak brilliance 10 9 (FEL) 10 4 (spont.) Average brilliance 10 4 (FEL) Degeneracy10 9 (FEL) 10 9 Total increase 10 6 FEL gain 10 3 e-properties undulator length

Published science cases for FEL radiation  Ultrashort duration of X-ray pulses  High number of photons per pulse  Coherent x-ray radiation Atoms, molecules, cluster Plasma physics Hard-condensed matter Surface & interface studies Materials science Chemistry Biology Nonlinear phenomena & quantum optics FEL physics

TTF-1 (Hamburg) LEUTL (Argonne) 1980 initial paper 2008 LCLS (Stanford) 2012 European XFEL (Hamburg) 2004 TTF (Hamburg) Roadmap towards an nm XFEL

The European XFEL project Original proposal (March 2001) part of the TESLA project. In October 2002 an standalone version was proposed Germany agreed to propose a site and to cover 50% of the building cost. Technical parameters are currently reconsidered. ~ 2000m~ 1200m 3 FEL and 2 beamlines for spontaneous synchrotron radiation with 10 independent experimental stations

The European XFEL at the DESY site

Towards the European XFEL Feb 2003BMBF indicates ‚green light‘ for European XFEL Oct 2003European Strategy Forum for Research Infrastructures evaluates Technical challenges Dec 2003XFEL enters EU Quickstart programme Jan 2004Formation of an European steering group Working groups on technological issues Working groups on administrative issues Update of scientific case End 2004Start plan approval procedure at DESY Workshops to define user/science requirements Early 2005European agreement on XFEL project Start of project 2006Start of construction 2012Start of commissioning

Diffusion, melting, ablation Phonon-phonon scattering Valence state excitations T e-h >> T L non-thermal thermal Equilibration (T e-h ~ T L ) Carrier-phonon scattering T e-h , T L  s s s s Ultrafast Processes

NRS Experiments at the XFEL Pump-probe investigations of dynamical phenomena Excitations in artificial spin chains, solitons Fast magnetic switching Magnon spectroscopy, Single – particle imaging Use of complementary techniques Neutron scattering, Magnetic x-ray scattering, Magneto-optics, Inelastic x-ray scattering, … Non-equilibrium phenomena