1. X-ray Pump-Probe Instrument
David Fritz
XPP Instrument Scientist
April 21, 2009

2. Time Resolved Scattering
The x-ray pump-probe instrument will take advantage of the ultrashort pulse duration of the LCLS to take snapshots of a photo-induced phenomena.
In general, the experiments performed as this endstation will use an ultrafast laser pulse to initiate a transient response in a system. The system will be probed using various x-ray scattering techniques. The time evolution of the response will be mapped by variably delaying the arrival time of the x-ray pulse with respect to the pump laser pulse.
The success of this end station will depend upon the ability to accommodate a wide variety of laser excitation techniques, samples, sample environments and x-ray scattering methods.
C. Siders

3. X-ray Pump-Probe Science
Phase Transitions
- Order / Disorder
- Metal/Insulator
Charge Transfer Reactions
- Photosynthesis
- Photovoltaics
- Vision
Vibrational Dynamics
Energy Dissipation and Flow
photo-
excitation
Stampfli and Bennemann Phys. Rev. B 49, 7299 (1994)
photo-
excitation
Page 3

4. XPP Instrument Goals\Requirements
Facilitate time-resolved X-ray scattering/spectroscopy using LCLS coherent hard x-rays (4-25 keV)
80 fs rms temporal resolution
Global Requirements (SP )
Capable of running in a shared beam mode using a future beam splitting monochromator
Instrument must be accessible while beam is delivered to FEH
Tailor and characterize X-ray and optical beam parameters
Spatial profile
Intensity
Repetition rate
Spectral bandwidth
Wavelength (optical laser)
Temporal profile (optical laser)
<1x10-7 Torr beamline vacuum

5. XPP Instrument Overview
Control Room
XPP
Endstation

6. XPP Instrument Overview
Photon Shutter
Requirement
Device
Tailor X-ray spatial profile ( > 50 microns)
X-ray Slits
Tailor X-ray spatial profile ( < 50 microns )
X-ray Focusing Lenses
Tailor X-ray intensity and spectrum
Attenuators
Tailor X-ray repetition rate
Pulse Picker
Tailor X-ray spectrum
Harmonic Rejection Mirrors
Characterize X-ray pulse intensity
Intensity Monitor
Characterize X-ray spatial profile
Profile Monitor
Sample orientation
Sample goniometer
Position X-ray area detector
Detector Mover
Measure X-ray scattering pattern
Detector
Photoexcitation of samples
Laser System
Characterize spatial profile, temporal profile, spectrum, intensity at a virtual sample
Laser Diagnostics
Intensity Monitor
Slits
Profile Monitor
Intensity Monitor
Slits
Focusing Lenses
Attenuators
Pulse Picker
Mirrors
Slits
Intensity Monitor
Profile Monitor
Sample Goniometer
Detector Mover
Profile Monitor
Intensity Monitor
Photon Shutter

7. XPP Instrument Overview
Detector Mover
Ultrafast Laser
Detector
Diagnostics
Sample Goniometer
X-ray Optics & Diagnostics
Page 7

8. Laser System XPP Laser System
Will utilize and expand upon AMO laser system
AMO Laser Requirements
> 3 mJ per pulse energy at sample (800 nm)
< 50 fs pulse duration
120 Hz
< 100 fs phase jitter to LCLS RF
Multipass amplifier
>20 mJ per pulse energy (800 nm)
Frequency conversion capability
OPA
Harmonic generation
Temporal pulse shaping capability
Diagnostics suite
System designed such that a non-laser trained user can perform an XPP experiment
Sufficient automation to control laser parameters
Sufficient engineering controls to provide safe working environment

9. (available in 2012 or before)
Scope
Early Science Scope
(available Mid-2010)
CD 4
(available in 2012 or before)
Sample Goniometer (Kappa & Tilt Platform)
X-ray Focusing Lenses
Detector Mover
Harmonic Rejection Mirrors
X-ray Detector System
Laser Power Amplifier
Laser System Optics and Diagnostics
Optical Parametric Amplifier
X-ray Slits
X-ray Attenuator/Pulse Picker
X-ray Diagnostics
X-ray Optics and Diagnostics Supports
Vacuum System
Controls & Data Systems
Hutch Facilities