NEH 2.2 will host 2 instruments, qRIXS and chemRIXS, that will be placed in series with attention paid to X-ray focal requirements, vacuum compatibility and beam pass-through capabilities. Dedicated laser delivery infrastructure will be implemented for each instrument, taylored for the specific requirements.
Time-tools will be located immediately in front of each endstation for accurate measurement of the relative time between the arrival of x-ray and optical laser pulses. Intensity fluctuations of the x-ray beam will be monitored on a shot-by-shot basis by a suite of fast single-photon sensitive detectors measuring either the fluorescence or electron yiled from the last 2 beamline mirrors.
The qRIXS instrument is comprised of a sample chamber and a rotatable spectrometer consisting of grating and detector assemblies (and auxiliary components), continuously covering the range of scattering angles 40-150 degrees in the horizontal plane.
The spectrometer is designed to achieve a target resolving power of 50,000 at 1 keV, with the option for lower resolving power, ~10,000, and higher throughput through the use of a second grating. The scattered x-rays will be horizontally collimated via a parabolic mirror to increase acceptance and facilitate future polarization-resolved studies.
The sample chamber is designed to accommodate the technique of Resonant Elastic X-ray Scattering (REXS). For this, a suite of in-vacuum point and 2D detectors will be implemented on a rotating arm to allow for rapid X-ray Absorption Spectroscopy (XAS) and (super)structural peak finding for sample orientation.
The chamber is equipped with an in-vacuum diffractometer with 6 axis of motion. Sample cooling down to 25 K will be possible. In-coupling of a wide variety of laser radiation, including long-wavelength THz beams, will be accommodated. Sample transfer will be facilitated via a load-lock chamber. In addition, provisions are made so that X-ray Photon Correlation Spectroscopy (XPCS) experiments on solid samples could be performed as well.
Advisory Panel qRIXS:
Yi-De Chuang- LBNL - ALS
Joe Dvorak - NSLS-II
Giacomo Ghiringhelli - Politecnico di Milano
Wei-Sheng Lee - SLAC
Ruben Reininger - APS
Tony Warwick - LBNL - ALS
DJ Huang - NSRRC
Alexander Fohlisch - BESSY
Gabriel Aeppli - PSI
The chemRIXS instrument is comprised of a sample chamber, designed with emphasis on soft X-ray spectroscopy experiments on liquid samples. The instrument is equipped with a suite of detectors allowing for XAS and XES measurements. The endstation is designed to support automated sample transfer via a retractable delivery system. A sample catcher coupled to a re-circulation system will be implemented.
Advisory Panel chemRIXS:
Jinghua Guo - LBNL – ALS
Andreas Scherz - EuXFEL
Philippe Wernet - BESSY
Anders Nilsson - Stockholm U., Stanford
Steve Kevan - LBNL – ALS