XPP Standard Configuration #1 for Run 18

Types of Experiments

With this standard configuration, XPP will be able to support time-resolved pump-probe hard X-ray diffraction measurements on various condensed matter systems in the form of crystals, alloys, and thin films

X-ray and X-ray Focus

X-ray energy will be fixed at 9.5 keV by the large offset monochromator using the diamond (111) configuration. We expect an average photon flux of 10¹⁰/pulse after the monochromator. Refractive Be lens will be available to deliver a beam size ranging from 10 to 200 μm at the sample. 1D focusing is available as well for grazing incidence geometry.

Optical Pump Lasers

Time-resolved experiments employing tunable femtosecond pulses will be supported under this standard configuration. In addition to the 800/400 nm 50 fs Ti:Sapphire fundamental/2^nd harmonic wavelengths, an OPA will be available to cover the wavelength range of 480-2400 nm. The optical pump beam will be propagating collinearly with the X-ray beam with about 2 degree crossing angle. We note that the efficiency of the optics and the performance of the laser and the OPA will not be the same for the entire wavelength range. The achievable peak intensity/fluence will be determined by the existing optical system and will not be modified. Contact the XPP scientists to discuss specific needs and to confirm whether they can be achieved in this standard configuration of the laser.

Timing Diagnostics

The spectral-encoding based timing tool will be available to provide shot-to-shot jitter measurement. We expect a time resolution of 100 fs considering the pump/probe pulse duration as well as the jitter correction accuracy.

Sample Manipulation and Temperature Control

The Huber Kappa goniometer will be used to position and orient the sample with 6 degrees of freedom. The sample mount shall fit the standard Huber goniometer head. The Oxford cryostream system will be available to provide in-air sample cooling down to 100 K. Heating up to 350 K can be delivered by the same system as well.

Every user group accepted and scheduled to use the XPP standard configuration will be required to know the crystallographic orientation of their sample.

Detectors

An epix10K or CSPAD detector will be mounted on the XPP detector robot arm for measuring the diffracted X-rays. The detector can be positioned to cover most of the upper reciprocal hemisphere. Typical sample-detector distance ranges from 100-1000 mm. In addition, PIPS diodes will be available to measure high intensity diffractions that are beyond the dynamic range of the epix10K or CSPAD detector.

XPP Instrument Staff

Diling Zhu, Matthieu Chollet, Mike Glownia, Roberto Alonso-Mori, Yiping Feng, Takahiro Sato, Matt Seaberg, Sanghoon Song

Parameter Table

To be considered for scheduling in this standard configuration, users will be required to include a table in the proposal that lists the specific experimental parameters to ensure compatibility with these configurations. If the experimental parameters are not compatible with the standard configuration or if the table of parameters is incomplete, the proposal will be reviewed and considered for scheduling as general user proposal. Please see the table of required parameters. No fundamental changes to the standard configurations will occur, but some details of the configuration may be updated in response to inquiries, so users should recheck the website before submitting your proposal to confirm that you have the latest information. Address any questions to the instrument staff.