Title
FEL based non-linear and time-resolved experiments
involving two-colour photoionisation of
Helium atoms and nanodroplets
Patrick O’Keeffe
CNR-ISM, Rome, Italy
Patrick O’Keeffe
Workshop on European XFEL, Bologna, 2014
Outline
Gas Phase beam line Elettra Synchrotron + Laser
Laser, probe
SR, pump
He(1s2)
LDM beam line FERMI
Laser,
probe
1. Circular Dichroism
in He Atoms
FEL, pump
He(1s2)
Patrick O’Keeffe
2. Pump-probe of dynamics of
Rydberg states inside droplets
Workshop on European XFEL, Bologna, 2014
GAPH- VMI: Photoelectron VMI –ion coincidence spectrometer
PSD
Electron
VMI
Delay line Detector
Cooled supersonic
jet
T
D
C
Synchrotron
Preamplifier
Computer
CFD
Ion
TOF
Set-up: O’Keeffe et al.
RSI 82 033109 (2011)
Patrick O’Keeffe
Workshop on European XFEL, Bologna, 2014
Combining an optical laser and synchrotron light
He
1s5p
He 1s2
Phase Difference
Ratio of radial int. of s/d waves
O’Keeffe et al. New J. Phys. 15, 013023 (2013)
Patrick O’Keeffe
Workshop on European XFEL, Bologna, 2014
Characteristics of Synchrotons/FEL
Limitation: SR+laser
typical 3rd generation beamline
1012 ph/sec
Elettra: 500MHz => 2000 ph/pulse, pulse width 70-100 ps
need processes with very high cross-sections
Slow processes on the 100s ps timescale
FEL: both of these problems are solved:
FERMI: 1014 photons/pulse @100nm, 30-100fs FWHM pulse width
1. Non – linear processes
2. Femtosecond time-resolved experiments
Patrick O’Keeffe
Workshop on European XFEL, Bologna, 2014
LDM-endstation
Pulsed molecular beam source: atoms, clusters, He droplets
Velocity map imaging spectrometer
Ion time of flight
•Lyamayev et al. J. Phys. B: At. Mol. Opt. Phys. 46 (2013) 164007
Patrick O’Keeffe
Workshop on European XFEL, Bologna, 2014
One Photon Ionization
He+ (1s-1)
FEL
He (1s2)
Patrick O’Keeffe
Workshop on European XFEL, Bologna, 2014
Two-photon ionization
Mazza et al.
Nat. Comm. 5, 3648 (2014)
doi:10.1038/ncomms4648
Pixel
IR Laser,
probe
Appearance of Sidebands
He+ (1s-1)
Pixel
FEL
He (1s2)
Polarisation dependence of the sideband signal
FEL
Patrick O’Keeffe
Laser
FEL
Laser
Workshop on European XFEL, Bologna, 2014
Dichroism
Mazza et al.
Nat. Comm. 5, 3648 (2014)
doi:10.1038/ncomms4648
Experimentally measured
CD
Þ Circularly polarised
FEL beam
Excellent agreement with
theoty
CD = -0.04
Þ Degree of circular
polarisation =
0.95+0.05/-0.08
Þ Sign of CD -> sign of helicity
Photoelectron
spectrum
Patrick O’Keeffe
CD =
(R – L) / (R+ L)
Left circularly polarised light
Workshop on European XFEL, Bologna, 2014
People
Gas Phase team
P O’Keeffe1, A Mihelic2, P Bolognesi1, M Coreno1, M Zitnik2, A Moise3, R Richter3 and L
Avaldi1
1CNR
Istituto di Struttura della Materia, Monterotondo Scalo, Italy.
Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana, Slovenia
3Elettra-Sincrotrone Trieste, Basovizza, Trieste, Italy.
2Jozef
LDM team
Viktor Lyamayev1, Yevheniy Ovcharenko2, Raphael Katzy1, Michele Devetta3, Lukas
Bruder1, Aaron LaForge1, Marcel Mudrich1, Ulrich Person1, Frank Stienkemeier1, Maria
Krikunova2, Thomas Möller2, Paolo Piseri3, Lorenzo Avaldi4, Marcello Coreno4, Patrick
O'Keeffe4, Paola Bolognesi4, Michele Alagia5, Antti Kivimäki5, Michele Di Fraia6, Nils B.
Brauer7, Marcel Drabbels7, Tommaso Mazza8, Stefano Stranges9,5, Paola Finetti10, Cesare
Grazioli10, Oksana Plekan10, Robert Richter10, Kevin C. Prince10,5, Carlo Callegari10
1Physikalisches
Institut, Universität Freiburg, Freiburg, Germany
für Optik und Atomare Physik, Technische Universität Berlin,
Berlin, Germany
3CIMAINA and Dipartimento di Fisica, Università di Milano, Milano, Italy
4CNR Istituto di Struttura della Materia, Monterotondo Scalo, Italy
5CNR Istituto Officina dei Materiali, Laboratorio TASC, Basovizza,
Trieste, Italy
6Department of Physics, University of Trieste, Trieste, Italy
7Federal Institute of Technology Lausanne (EPFL), Lausanne,
Switzerland
8European XFEL, Albert-Einstein-Ring 19, Hamburg, Germany
9Department of Chemistry, University La Sapienza Rome, Rome, Italy
10Elettra-Sincrotrone Trieste, Basovizza, Trieste, Italy.
2Institut
Patrick O’Keeffe
Workshop on European XFEL, Bologna, 2014
People
Pulse length and Dichroism on Helium atoms
T. Mazza1, M. Ilchen1, A. J. Rafipoor1, S. Dusterer2, K. Ueda3, J. T. Costello4 A. K. Kazansky5,6,7,
N. M. Kabachnik1,3,7,8, M. Meyer1
European XFEL GmbH, Albert-Einstein-Ring 19, Hamburg, Germany
Deutsches Elektronen-Synchrotron (DESY), Notkestrasse 85, Hamburg, Germany
3 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai,
Japan
4 National Center for Plasma Science and Technology and School of Physical Sciences,
Dublin City University, Dublin, Ireland
5 Departamento de Fisica de Materiales, UPV/EHU, San Sebastian/Donostia, Spain
6 IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
7 Donostia International Physics Center (DIPC), San Sebastian/Donostia, Spain,
8 Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University, Moscow, Russia
1
2
Dynamics in Helium Nanodroplets
PI: Marcel Mudrich1
1Physikalisches
Institut, Universität Freiburg, Freiburg, Germany
Laser group
M. Danailov, A. Demidovich, et al. ,
Patrick O’Keeffe
Workshop on European XFEL, Bologna, 2014
SQS Scientific Instrument
12
Slide courtesy of Michael Meyer
Optimization of the design
- Focal distances
- Internal geometry
- Access of optical laser
KB optics
Versatility of the design
- Exchange of chambers
- Exchange of standard components
NQS
AQS
SQS Scientific Instrument
Slide courtesy of Michael Meyer
MBES
VMI
XUV
Spectrometer
AQS
Atomic-like Quantum Systems
Targets: atoms & small molecules
Molecular beam
Vacuum: 10-11 mbar
Focus: ≤ 1 mu à 50 mu
electrons, ions, photons
eTOF
Molecular beam
- HR electron spectroscopy
- Angle-resolved spectroscopy
- Non-dipole studies
- HR fluorescence spectroscopy
- e / e – coincidences
- e / ion - coincidences
SQS Scientific Instrument
Slide courtesy of Michael Meyer
COLTRIMS
DSSC
Cluster
sources
eTOF
NQS
Nano-size Quantum Systems
Targets:
cluster, nano-particles, bio-molecules
Cluster source, liquid jet, aerosols
Vacuum: 10-9 - 10-10 mbar
Focus: ≤ 1 mu à 50 mu
electrons, ions, photons
- Diffraction Imaging
- Ion/electron spectroscopy
- hn / ion – coincidences
- e / ion – coincidences
- hn / e / ion – coincidences