XPP (X-ray Pump Probe)

XPP restarts user operation from Run26 from April 2026 with "120 Hz". Since XPP is targeting to take high repetition rate X-rays in 2 years and will switch our optical laser from 120 Hz to 10s kHz system, we recommend intense THz and Mid-IR users to conduct experiments before the additional upgrade. For details, please contact the XPP scientists. 

The XPP instrument predominantly uses ultrashort optical laser pulses to generate transient states of matter which are subsequently probed by hard X-ray pulses from the LCLS. The X-ray pulses help to reveal structural dynamics initiated by the laser excitation at the timescale of atomic motions in solid, liquid and gaseous specimens. 

The instrument design emphasizes versatility. To maximize the range of phenomena that can be excited and studied, the laser pulse energy, frequency, and temporal profile can be matched to the scientific problem. X-ray absorption and emission spectroscopy, diffraction and scattering are typical tools for probing the laser-induced structural changes. These experiments require the union of four experimental capacities: the generation and delivery of X-ray and laser pulses to the sample, the preparation of the excited state in the sample, and the detection of the X-ray signal.

For Run27, XPP will offer the following capabilities.

1. Time resolved diffraction in air or in vacuum with low temperature environment down to 20K (16K~ with best effort)
2. Mini split and delay optics for XPCS, X-ray pump and X-ray probe type experiments
3. Wide angle X-ray scattering

For more information about the XPP instrument, please read the specification page, the standard config page and the following article:

• Chollet et al. The X-ray Pump-Probe instrument at the Linac Coherent Light Source. J. Synchrotron Rad. (2015), 22, 503-507​

XPP Location

Near Experimental Hall (NEH), Hutch 3

See complete instrument map

XPP Videos

For more XPP related videos, see the LCLS XPP playlist on YouTube.

Download flyover animation (right click and save link as):

mp4  (16.3 MB)