A 1-D Imaging RIXS Spectrometer for Ultra-fast Phenomena and NonLinear Science at European XFEL

Joseph NordgrenDept. of Physics and Astronomy, Uppsala University, Sweden

Outline

• RIXS tutorial and scientific opportunities

• Experimental considerations

• The proposed instrument

RIXS publication rates

L.J.P Ament, et al, arXiv:1009.3630v2

# publications # citations

Valence-Core X-ray Spectroscopy

E. Joseph Nordgren

20:th ICORS

EF

Valence band

Conduction band

Core level

Photon outPhoton in

Examples

Valence-Core X-ray Emission

Y. Zhang et al.,Thin Solid Films, 515,

394–400 (2006)

J. Guo and J.Nordgren, J. Electr. Spectr.

110–111, 105-134 (2000)

Carbon allotropes Phthalocyanines

C K

Graphite

C70

C60

Benzene

Diamond

N XES

C XES

UPS

C XES

E. Joseph Nordgren

20:th ICORS

EF

Photon out

Valence band

Conduction band

Core level

Resonant X-ray emission

Photon in

Resonant Inelastic X-ray Scattering

(RIXS)

EFValence band

Conduction

band

DE

Core level

F(w,w´) = S S d(Eg+ hw - Ef -hw´)f m

<f D m><m D g>Eg + hw - Em - iGm

2

Inelastic scattering cross section

(Kramers-Heisenberg formula):

Features of RIXS spectra:

• Site selectivity

• Symmetry selectivity

• Probing of low-energy excitations

• Sub-natural width spectra

• Ultra-fast dynamics

• Bulk and buried structures

• Band dispersion

Review: J. Nordgren et al., in Handbook of Solid State Spectroscopy,

Springer 2006, Ed. W.R. Wij

Ni Ni Ni Ni Ni Ni Ni

Ni Ni Ni Ni Ni NiNi

N N

N N

N

N

Site and Symmetry Selectivity in

Resonant X-ray emission

A. Nilsson, et al, Surf. Sci. Rep., 55, 49 (2004)

Ni

s

p

p

p+s

Analysis Capability of RIXS for Cu

compounds

K. Kvashnina, et al, J. Phys. Cond. Mat. 19, No. 226002 (2007)

E. Joseph Nordgren

IWSXR, Okazaki 2006

Cu 2p

RIXS

Malachite CuCl2

Cu 2p

RIXS

Elementary Excitations in

Strongly Correlated Materials

Ground state

Core states

Charge transfer

d-d

Magnons

Phonons

Orbitons

For original work, see e.g., S. Butorin, et al., Phys. Rev. Lett., 77, 574 (1996)

For excellent review, see L.J.P. Ament, et al., Rev.M od..Phys., 83, No.2 (2011)

F(w,w´) = S S d(Eg+ hw - Ef -hw´)f m

<f D m><m D g>Eg + hw - Em - iGm

2

Experimental setup for RIXS

e-

Imaging detectorGratings

Undulator

(Slit)Monochromator

SampleSpectrometer

Synchrotron facility

XUV

Spec.

Pump-probe experiments with RIXS

FEL pulse

Laser pulse

RIXS

Thin sample

Yu-Ping Sun, Faris Gelmukhanov PHYSICAL REVIEW A 81, 013812 (2010)

Non-linear processes in

FEL beam interaction

4-wave mixing

Spectral broadening

stimulates 3s-2p

4s-2p

Detector

Cylindrical grating

Cylindrical mirror

FEL beam

Sample

Cylindrical mirror imaging RIXS

Soft X-ray grating spectrometers

Zero order

Positive order

Negative order

Detector

Detector

VLS grating

CLS grating

VLS spectrometer

Rowland spectrometer

sin f – sin f’ = nl/d

f f’

Spatial resolution for cylindrical mirror

Principle of Wolter Microscope

J.A. Jackson, LLNL report UCRL-TR-220019 (2006)

Wolter, H. 1952, Annalen der Physik (6. Folge) 10, 94

Comparison Cylindrical mirror – Wolter pair

@ 150 mm detector resolution

10 ps (for cvacuum)

Outline of 1-D Imaing RIXS Spectrometer

FEL beam

Wolter mirror pairGrating

Detector

Rowland circle

SQS

Imaging detectors for Soft X-rays

Issues:

Resolution - < 50 mm

Sensitivity at various incidence angles

Speed – 220 ns pulse separation

Back thinned CCD

MCP with various read-outs

Pixelled silicon devices with on-board memory

Striped Time Delay Detector

64 x

Fast DAQ

Surface Concept Company

Temporal resolution - Wolter optics

@ 150 mm detector resolution

10 ps

Photon Energy Resolution

Photon Energy Resolution

Other Applications of 1-D Imaging RIXS

• Spectroscopic imaging

– Non-homogeneous samples

– Graded sample composition

• RIXS maps

RIXS Maps

RIXS Map Recordning by 1-D

Imaging Spectrometer

Dispersed photon beam

Homogeneous sample

Position coded RIXS

Vertical to horizontal dispersion

Grazing inc. mirror

at ~45 deg. slantVertical dispersion Horizontal dispersionFrom mono

Acknowledgement

• Marcus Agåker

• Jan-Erik Rubensson

• Carl-Johan Englund

• Michael Meyer

• Monica Turcato

• Markus Kuster