Scientific Opportunities for the Dynamic X-ray Scattering (DXS) Instrument at LCLS-II-HE Workshop 2021

Date:

November 17th, 2021

Location:

Virtual

Overview

As the LCLS-II-HE (HE) upgrade project is nearing its CD-2/3 approval, the preliminary designs of experimental stations are being developed with the help of the user community. With unprecedented average spectral flux (photons/s/meV) promised by the HE upgrade, one of the most exciting projects is the Dynamic X-ray Scattering (DXS) instrument, featuring X-ray Inelastic X-ray Scattering (IXS) and Photon Correlation Spectroscopy (XPCS) end stations. 

To create a forum for the scientific community to discuss potential science applications that could be enabled by DXS, we are initiating a series of meetings. The first of these meetings will be held on November 17, 2021. In addition to the introduction of the preliminary instrumentation plans, there will be three plenary talks to set the stage for the follow up meetings. The follow-up meetings will be announced as the plans solidify, and will be focused on topical areas that are expected to refine and guide the instrumentation plans.

Charge:

• Identify the most compelling (transformative) science drivers for the DXS instrument - particularly areas that can exploit the unprecedented average spectral flux (photons/s/meV). What will be the impact if the proposed research is successful? Consider both:
  • Ideas consistent with Day-1 DXS and LCLS-II-HE capabilities
  • Longer-term ideas with high potential science impact that might exploit advanced performance, e.g. higher photon energies, higher ave. spectral flux from seeding etc.​​
• Outline the proposed experimental method(s) and key instrument requirements, particularly highlighting the requirements for the DXS instrument and LCLS-II-HE capabilities. This should clarify:
  • Why LCLS-II-HE and DXS are essential for this science
  • What are the essential incident X-ray parameters (focus, BW, tunability, polarization etc.)?
  • What are the sample environment requirements (pressure, temperature, applied fields etc.)?
  • What are the conventional laser requirements (wavelength, pulse energy etc.)?
  • What are the essential spectrometer and detector requirements?
• Consider the cross-over between IXS (energy-domain) and XPCS (time-domain) approaches
  • Are IXS or XPCS methods clearly preferred for particular science opportunities (and why), and what opportunities might fall in areas that might be accessible with either method? 

The objective of this workshop is to refine the scientific drivers for the DXS instrument, particularly high-impact science areas that can exploit the high-resolution IXS capabilities and the cross over between IXS and XPCS techniques. IXS has traditionally been a synchrotron-based technique since the average spectral flux of the existing FEL sources had been inadequate for these low-count experiments. Therefore, there is limited overlap between the ultrafast sciences and IXS communities. One of the awaited outcomes of this workshop is to bring these two communities together and deliberate potential avenues to explore. Additionally, we expect to discuss and improve the instrument parameters answering to the desires of the community, including pump and probe beam characteristics, and sample environment capabilities.

Committee:

DXS Instrument Advisory Panel

• Yong Cai, Brookhaven National Laboratory
• Anders Madsen, European XFEL
• Michael Krish, ESRF
• Harald Sinn, European XFEL 

IXS Task Force

• Giacomo Coslovich
• Georgi Dakovski
• David Fritz
• Paul Fuoss
• Jerome Hastings
• Wei-Sheng Lee
• Robert Schoenlein
• Mariano Trigo

Supporting Material:

Welcome and Charge (PDF)

DXS Instrument Overview (PPT)

Participants: