Background and Present Status from AMO Instrument Team. Team Organization. 2. Proposed Scientific Plan. The First Experiment. 4. Future Plan. Historical Facts. April 2004: LCLS puts out a call for Letters of Intent (LOI) category A: science & end-station construction
2. Proposed Scientific Plan.
4. Future Plan.
category A: science & end-station construction
category B: science
category C: instrument design
October 2004: Ultra-fast science workshop
Marriage of Synchrotrons + Ultrafast Communities
~ Twenty Additional Scientists Expressed Interest at the October 2004 Workshop
5. Communication with Broader Team at Conferences (Wisconsin W. 8/04; DOE M. 9/05; DAMOP 5/06)
6. E-mail Updates to Broader Team when Necessary (seek input, communicate news)
Discussions/communication led to determine the instrumentation needs for first experiments!
7. Conceptual Design and Instrument Budget was submitted and Accepted by LCLS.
8. Synergy between the PULSE Center and AMOS
9. Workshop to Stimulate Theory (ITAMP 06-06)
10. Met with:
-----LCLS Optics Group
------Pump-Probe Team to Explore Common Interest and will Continue to Meet.
11. Plan to Meet with Imaging Group to Explore Shared Experimental System?
12. Held Ultrafast x-ray Summer School June 2007
Ken Taylor (Ireland) Possibilities for few- and many-electron atoms & ions in XFEL pulses
David Reis (UM) Synchronization issues for pump-probe experiments at LCLS
Robin Santra (ITAMP) Cluster physics at high photon energies
Anders Nielsson (SSRL) Time resolved spectroscopy for studies in surface chemistry and electron driven processes in aqueous systems
Chris Greene (UCB) Multiphoton ionization processes in free atoms and clusters
John Bozek (ALS, LBNL) Atoms, molecules, clusters and their ions studied with two or more Photons
Ali Belkacem (LBNL) Inner-shell ionization and de-excitation pathways of laser-dressed atoms and molecules
Keith Nelson (MIT) Give him 10 minutes max and then let's get back to reality
Ernie Glover (LBNL) X-ray/optical wave mixing
Elliott Kanter (ANL) Hollow neon atoms
Auger DecayLCLS High Field Beam will Probe:
Sequential(or “Cascade”) Multi-Auger Decay
( 3-10% of single Auger)
High Field Studies in Atoms
2-photon, 2-electronX-Ray Strong Field Experiment
x-ray multiphoton ionization
1013 W/cm2Low-Frequency Physics → High Frequency
Low frequency regime
Intense photon source
Highly ionizing source
Optical Frequency = (Ip/2Up)1/2 -1; Up=I/4ω2 (au)
FLASH Experiments (Lambropoulos)
PRL 94, 023001 (2005)
Theory Available! Calculate the rate of production of highly charged Xei+ ions produced by direct multiphoton absorption, to compare with experiment.
TOF Spectrum for Atomic Xenon Multiphoton Ionization (Lambropoulos)(Wabnitz et al.’05 )
Wabnitz et al. ‘05 (Lambropoulos)
First LCLS Experiment: K-Shell in Ne (Lambropoulos)1.Photoionization2. Auger Decay3. Sequential Multiphoton Ionization4. Direct Multiphoton IonizationTheory:Double-K ionization in Ne due to absorption of 2-photons by 1 atom for hγ>932 eV is predicted to be 100%
Ne K-edge ~ 870 eV (Lambropoulos)
The probability of two-photon absorption by 1s2 -shell accompanied by the creation of double 1s-vacancies predominates over the probability of the process of two-photon one-electron excitation/ionization of the 1s2 shell in the range of x-ray photon energies ≥ 930 eV.
Rohringer & Santra, PRA 76, 033416 (2007)
Rohringer & Santra, PRA 76, 033416 (2007)
Power of TOFs: (Lambropoulos) Inner-Shell Resonances in Ar; 2 p Excitation to Rydberg States(ALS)
LCLS: K-Shell ArHow would the ratio of Doubly Ionized Ions (Auger decay) Compares to Singly Ionized Ions due to spectator Auger decay?
Resonant shake-off of two electrons.
High Field Studies in Molecules (Lambropoulos)
HBr 3d (Lambropoulos)(ALS) Excitation/Ionization2D Map; Angle-Resolved;e- TOFs
LCLS: HBr, Br2 2p & 2s Ionization
Ion Imaging : (Lambropoulos)Fragmentation Decay Channels of CO22+ Subsequent to K-Shell Photoionization and Auger Decay of CO2.
Identify different fragmentation mechanisms
Fragment Momentum Correlation Plots (Lambropoulos): Fragmentation Decay Channels of CO22+ Subsequent to K-shell Photoionization and Auger Decay of CO2.
High Field Studies in Clusters (Lambropoulos)
Cluster Studies at FLASH in Hamburg (Lambropoulos)
Xenon Cluster size 2500 atoms
Wabnitz et al, Nature 420, 482 (2002)
Molecular dynamics simulations indicate (Lambropoulos)
that standard collisional heating cannot fully account for the strong energy absorption.
In contrast with earlier studies in IR and VUV spectral regime, we find NO evidence for electron emission from plasma heating processes; Multistep ionization process is dominant
hν=37.8 eV, <N>~100, I=3x1013W/cm2 @25 fs
Is it a Coulomb Explosion Picture(as in intense optical or near IR ultrafast laser pulses) OR
Explosion due to Hot Nanoplasma(multiple scattering from the cluster atoms can confine electrons yielding a nanoplasma); Explosion Time can be Different
OR, New mechanisms??
4d Photoelectron regime, we find NO evidence for electron emission from plasma heating processes; Multistep ionization process is dominantSpectrum of Xe Clusters at hn=135 eV
Velocity Map Imaging Coincidence System (PEPIPICO) @ ALS regime, we find NO evidence for electron emission from plasma heating processes; Multistep ionization process is dominant
80 mm position-sensitive multi-hit hex-anode detector (Roentdek)
Rolles et al. Nucl. Instr. and Meth. B 261, 170 (2007).
Fragmentation of Rare Gas Clusters @ ALS regime, we find NO evidence for electron emission from plasma heating processes; Multistep ionization process is dominant
PEPIPICO coincidence map for photoionization at hv=216 eV regime, we find NO evidence for electron emission from plasma heating processes; Multistep ionization process is dominant
High Field Studies in Ions regime, we find NO evidence for electron emission from plasma heating processes; Multistep ionization process is dominant
Size Selected Production
Size and Charge Selected Detection
Absolute cross sections: measurements of overlaps, photon & ion fluxes and detector efficiencies.
LCLS: S K-shell
PR A 72, 050701(R), 05
H, S-Off; S-Up+Seq-Aug
Pump-probe experiments of molecules (state-selected): - Launch a molecule on a particular potentially energy surface - Watch temporal evolution with angle-resolved inner-shell PES
Photodissociation Dynamics of I S2-: Pump-Probe Experiments
LCLS, Probe with >800 eV photons
2P1/2 and 2P3/2 spin-orbit states of I.
I- photoelectron spectrum
Neumark et al. Chem. Phys. Lett, 258 (1996) 523.
Dissociation Time scale: Rise time of electron signal reaches 50% of its maximum value by 100 fs.
Photodissociation Dynamics of I (ALS)2-
Kolsoff et al.