XPP Standard Configurations

XPP Standard Configuration #1 for Run 22

Types of Experiments

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

X-ray and X-ray Focus

X-ray energy will be fixed between 9-13 keV by the large offset monochromator using the diamond (111) configuration. We expect an average photon flux of 10¹⁰/pulse after the monochromator. Narrow bandwidth option is avaliable by using Si(333), Si(440), Si(444), Si(660), or Si(555) channelcut crystal monochromator. Only 1D focus is avaliable for the narrow bandwidth option in Run 22 for the standard configuration.

The default polarization is vertical.  Horizontal and circular polarizations and switching capability with the phase retarder are available. Compound refractive lenses will be available to deliver a beam size ranging from 10 to 300 μm at the sample. 1D focusing is available as well. 

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. THz excitation based on optical rectification in LiNO₃ is also available in this standard configuration, providing peak field strength beyond 500kV/cm. The pump beam will be propagating collinearly with the X-ray beam. A small crossing angle up to 7 degrees can be accommodated for most wavelengths too. 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 laser parameters 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 120 K. Heating up to 400 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 Jungfrau 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, Diodes will be available to measure high intensity diffraction peaks that are beyond the dynamic range and damage threshold of the pixelated detectors.

XPP Instrument Staff

Takahiro Sato, Diling Zhu

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.

XPP Standard Configuration #2 for Run 22

Types of Experiments

With this standard configuration, XPP will be able to support time-resolved pump-probe hard x-ray forward small and wide angle scattering (SAXS & WAXS) from solid samples.

X-ray and X-ray Focus

Available X-ray photon energy ranges from 9-18 keV when pink beam is requested. For monochromatic, photon energy shall be ~10keV. We expect an average photon flux of 10¹²/pulse for pink mode and 10¹⁰/pulse if operating with the diamond (111) multiplexing monochromator. Refractive Be lens will be available to deliver a beam size ranging from 10 to 200 um at the sample. 1D focusing is available as well.

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/2nd 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

A vacuum chamber with translation stages will be available. Angular alignment of the sample will be limited to 1 rotation axis covering up to 120 degrees.

Detectors

An ePix10k 2.1Mpixel detector will be mounte on the XPP robotic detector positioner for WAXS, and downstream on detector positioning stages at distances up to 10 meters for SAXS.

XPP Instrument Staff

Matthieu Chollet, Matthias Hoffmann, Takahiro Sato, Matt Seaberg, Sanghoon Song, Yanwen Sun, Diling Zhu.

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.

XPP Standard Configuration #3 for Run 22

Types of Experiments

With this standard configuration, XPP will be support time-resolved hard X-ray diffraction and scattering at cryogenic temperature down to 30K for solid samples.

X-ray and X-ray Focus

X-ray energy will be fixed between 9-13 keV by the large offset monochromator using the diamond (111) configuration. We expect an average photon flux of 10¹⁰/pulse after the monochromator. The default polarization is vertical.  Horizontal and circular polarizations and switching capability with the phase retarder are available. Compound refractive lenses will be available to deliver a beam size ranging from 10 to 300 μm at the sample. 1D focusing is available as well. 

Optical Pump Lasers

to be added.

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

In-vacuum diffractometer and cryostat is available to provide sample motion and temperature control. Large Kapton windows on the vacuum chamber allows the diffracted and scattered x-rays to exit the chamber, and measured by the x-ray 2D detectors outside.

More details to be added

Detectors

An ePix10k 2 megapixel detector or a Jungfrau 1 megapixel detector will be mounted on the robotic detector positioned and be available for the measurement.

XPP Instrument Staff

Hasan Yavas, Takahiro Sato, Diling Zhu, Matthieu Chollet.

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.