Slide: 1 IXS with sub-meV resolution: opening new frontiers in the study of the high frequency dynamics Giulio Monaco ESRF, Grenoble (F) outline: High resolution IXS at storage rings Small samples Disordered systems at the nanometer scale High resolution IXS at the XFELO

Slide: 2 Inelastic x-ray scattering (IXS) E = E in – E out k = k in – k out  E in, k in E out, k out Sample IXS requires optimized setup at 3 rd generation synchrotron E ~ 18 keV ESRF ~ photons/s in  E~2 E ~ 10 keV ESRF ~ photons/s in  E~300 meV) 1. IXS at storage rings G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013 Dynamic structure factor Van Hove density correlation function

Slide: – first IXS measurements E i = 18 keV  E=55 meV 1. IXS at storage rings G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013

Slide: – development of ESRF - I -~ cubes of 0.6x0.6x2.3 mm 3 - perfect crystal properties - collection of sufficient solid angle - IXS feasible at large third generation synchrotron radiation sources (ESRF, APS, SPring-8) - steady development of undulators since the 1990s 1. IXS at storage rings G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013

Slide: 5 ~500-fold decrease in focal spot size during the last 15 years! Current figures: 7 x 14  m 2 (V x H) O 13 GPa Single-crystal size: 30x30x10  m 3 ~10  m is the ultimate goal for the focal spot size for IXS at the ESRF (its contribution to the exchanged momentum resolution already matches that from the finite collection angle) 1. IXS at storage rings G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ – development of ESRF - II

Slide: 6 Diamond anvil cell (New) materials in small quantities (10 -5 mm 3 ) Very high pressures > 1 Mbar Study of surface dynamics Ø 45  m t=20  m bcc Mo single crystal ruby helium Scientific themes: small samples 2. Small samples G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013

Slide: 7 Applications: complementarity to INS Wong et al., Science 301, 1078 (2003); PRB 72, (2005) typical grain size: 90 μm foil thickness: 10 μm Strain-enhanced recrystallisation of fcc Pu-Ga (0.6 wt%) alloy G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ Small samples

Slide: 8 Brillouin scattering ILS Raman scattering INS 500 m/s 5000 m/s IXS IUVS Scientific themes: disordered systems  Interplay between structure and dynamics  Relaxations at the picosecond time scale 3. Disordered systems G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013

Slide: 9 Free particle regime: impulse approx. Microscopic regime  not complete understanding  Relaxation processes invoked to account for the spectral shape and the broadening of the excitations Microscopic dynamics: the long standing puzzle Macroscopic regime  hydrodynamics v=ħ  /q G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ Disordered systems

Slide: 10 The dynamic structure factor of sodium The spectrum of the liquid is a broadened version of the one for the powder Inelastic x-ray scattering ID16, E= keV, DE=1.4 meV Giordano & g.m., PNAS 107, (10) G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ Disordered systems

Slide: 11 Long Trasv The order fingerprint P L Theory First Brillouin zone: The longitudinal and transverse dispersion curves in the liquid reflect those for the powder (density scaling of frequencies for the solid) Giordano & g.m., PNAS 107, (10) G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ Disordered systems

Slide: 12 The disorder fingerprint  Local order  dispersion  Average disorder  broadening Giordano & g.m., PNAS 107, (10) G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ Disordered systems

Slide: 13 Boson peak and van-Hove singularity - I Chumakov, g.m. et al., PRL 106, (2011) G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ Disordered systems

Slide: 14 Chumakov, g.m. et al., PRL 106, (2011) Boson peak and van-Hove singularity - II G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ Disordered systems

Slide: 15 Breakdown of the Debye approximation & appearence of a Reyleigh scattering regime on the mesoscopic lengthscale of glasses g.m. & Giordano, PNAS 106, 3659 (09) Glasses: the nanometer length scale G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ Disordered systems

Slide: 16 At low q (< 1 nm -1 ) macroscopic hydrodynamics is recovered g.m. et al., PRE 60, 5505 (1999) G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ Disordered systems Liquids: the nanometer length scale At high q (> 1 nm -1 ) the dynamics is q-dependent Pontecorvo et al., PRE 71, (2005)

Slide: 17 High resolution monochromator Yabashi et al., Rev. Sci. Instr. 72, 4080 (2001) (+,-,-,+) configuration (calculations for 10  rad divergent beam) Shvyd’ko, X-ray optics, Springer (2004) G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ IXS at the XFELO

Slide: 18 High resolution IXS G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/ IXS at the XFELO

Slide: 19 ESRF & XFEL vs XFELO: 0.85 Å & in 9·10 -5 relative bandwidth: intensity: 7· ·10 16 ph/s intensity in 0.1 meV: 5· ·10 11 ph/s ID18 1·10 14 ph/s in 2.1 eV 6·10 13 ph/s in 9·10 -5 rel. bandwidth XFEL ESRF analyzer efficiency Energy resolution: 0.5  eV Average transmission: 30% Solid angle collection at q=2 nm -1 : 100% Ratio: ~100! 0.75 meV 20% 9% ID16 3.4·10 9 ph/s in 0.7 meV 23.7 keV, in 3·10 -8 rel. bandwidth ID18 8·10 9 ph/s in 0.5 meV 14.4 keV, in 3·10 -8 rel. bandwidth XFELO intensity: 1·10 15 ph/s in 1 meV intensity in 0.1 meV: 1·10 13 ph/s !!! 4. IXS at the XFELO G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013

Slide: 20 Conclusions 1.XFELO promises to offer 10 4 times more intensity than the ESRF and 10 2 more than the XFEL when used as a CW machine. Experiments not feasible at storage rings will be feasible with the XFELO, and those already feasible at storage rings will be much faster. 2. Small samples will be accessible for single crystal work, this will go by far beyond current capabilities at storage rings. 3. High resolution IXS experiments with 0.1 meV resolution will likely be possible. This will allow the exploration of disordered systems (liquids, glasses) at the nanometer scale. 4. With the numbers now at hand, high-resolution IXS experiments are technically already basically within reach! G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013

Slide: 21 and thank you for your attention! Many thanks to A. Chumakov (ESRF) G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013

Slide: 22 Inelastic x-ray scattering (IXS) E = E in – E out k = k in – k out  E in, k in E out, k out Sample IXS requires optimized setup at 3 rd generation synchrotron E ~ 18 keV ESRF ~ photons/s in  E~2 E ~ 10 keV ESRF ~ photons/s in  E~300 meV) 1. IXS at storage rings G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013 Dynamic structure factor Van Hove density correlation function

Slide: 23 Inelastic x-ray scattering quasielastic phonon valence electron excitations plasmon Compton profile core-electron excitation access to a rich excitation spectrum 1. IXS at storage rings G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013

Slide: 24 undulator premonochromator focusing mirror backscattering monochromator sample analysers detectors Energy scans are performed by tuning the main monochromator temperature Modern beamline layout G. Monaco –IXS with sub-meV resolution – Pohang, 14/02/2013