TMO - Time-resolved AMO


The Time-resolved atomic, Molecular and Optical Science (TMO) instrument (NEH 1.1), one of the three new LCLS-II instruments with a energy range from 0.25 to 2 keV, will support a wide range of science including gas phase photochemistry, attosecond electron dynamics, and the study of nanoscale systems. TMO will support an array of experimental techniques and features two X-ray focus positions. The NEH beamline 1.1  science end station, will be configured to take full advantage of both the high per pulse energy from the copper accelerator (120 Hz) as well as high average intensity and high repetition rate (1 MHz) from the superconducting accelerator.  

Endstation Descriptions

The initial TMO focus spot or interaction point, IP1, is optimized for performing high energy, high resolution, time-but also angular-resolved photoelectron spectroscopic measurements. This interaction point features an array of standardizied, modular endstations. Depending on the photon energy, IP1 X-ray photon fluence can reach the high 1019 photons/cm2 range with superconducting Linac, and high 1020 photons/cm2 range with copper accelerator at 120 Hz.

The second TMO focus spot (IP2) features the new Dynamic REAction Microscope (DREAM) endstation which is a reaction microscope (or COLTRIMS type) spectrometer as a standard configuration. A second set of focusing mirrors defocus the IP1 spot to produce sub-mircon x-ray focal spots. The reaction microscope techniques is well suited for accumulating data on the event-by-event basis at the rep rates in excess of 100 kHz fully utilizing the LCLS-II capabilities. Photon fluence in IP2 will reach beyond 1021 photons/cm2 with superconducting Linac X-rays, while with copper accelerator it will be over 1022 photons/cm2 at 120 Hz.

Pump-probe timing resolution of X-ray with optical laser pulses can be expected to exceed 10 fs for both endstations.


Parameter  Value 
Undulator Source SXU
Photon Energy Range   250-2000 eV
Focused Beam Diameter (FWHM) < 1.5 μm (IP1) & < 300 nm (IP2)
X-ray Bandwidth 
  • 3 × 10−3 
  • 1 × 10−4 (seeded) 
Beamline Transmission  ~ 80% (IP1) & ~ 60% (IP2)
Repetition Rate up to 929 kHz
X-ray Power Limit 200 W
Optical Laser 200 nm to 17 μm with varying power, repetition rate, and pulse duration 
Primary X-ray Techniques
  • Electron/Ion coincidence measurements in a reaction microscope (or COLTRIMS) type spectrometer
  • High-Energy Electron Spectroscopy 
  • X-ray Pump / X-ray Probe, Optical pump / X-ray Probe

Advisory Panel

  • Christoph Bostedt - PSI, ETH Zurich
  • Reinhard Dörner - Frankfurt
  • Gilles Doumy – Argonne
  • Oliver Gessner - LBNL - CSD
  • Markus Guehr - U. Potsdam
  • Daniel Rolles - KSU
  • Thorsten Weber - LBNL - CSD
  • Nora Berrah - U. Conn
  • Adrian Cavalieri - MPSD, CFEL, U. Hamburg
  • Jon Marangos - ICL
  • Artem Rudenko - KSU
  • Richard Squibb - GU