Perhaps the most conspicuous change is a reorganization of the user space (Figure 1), primarily to improve access and usability of the G2 and G3 areas, especially for large groups. Among the changes are the creation of a "G3 annex" space opposite the G3 hutch to store, maintain and prepare heavy equipment, such as UHV chambers, for in situ experiments. This space occupies Arthur Woll’s former office, which has been relocated to room 316 Wilson Lab.
A second major change is that the G-line chem room (Figure 2) has been significantly upgraded and enhanced in order to support the MacCHESS BioSAXS program, which has moved from F2 to G1. The chem room now houses a dedicated BioSAXS sample preparation area, now has high-quality ultrapure water on tap and all the equipment you need to prepare a wide variety of buffers. This move coincides with a major upgrade to F2 for high energy upgrade for structural materials, and has the benefit of higher flux for BioSAXS users owing to the use of synthetic multilayer optics. Moving forward, G1 will house both BioSAXS while continuing to serve as a general purpose high flux station, with a particular emphasis on in situ, time resolved SAXS and GISAXS.
Over the past several years, a series of incremental improvements and upgrades to G2 optics, detectors, and hutch equipment combine to make it a fantastic, general purpose station for x-ray reflectivity and high resolution diffraction, especially for thin films. G2 now routinely delivers 10^11 photons / second at the sample in a 0.2 mm x 2.0 mm spot. Most often, this beam is used in conjunction with soller slits and a 640-pixel linear diode array built at Brookhaven National Laboratory to provide good in-plane angular resolution. This arrangement is particularly advantageous for studying organic and mixed-phase thin films. Alternatively, the diode array and soller slit arrangement may be replaced by one of several Pilatus 100K (Dectris) detectors now available at CHESS.
To improve support for in-situ thin film and surface science at the G3 hutch, a new, custom optical table (Advanced Design Consulting) has been commissioned (Figure 3 shows the new ADC table with CHESS graduate student Howie Joress). This table constitutes a significant improvement in resolution and reliability, and significantly impacts the capability of G3.
