[en] RapiData provides two days of high-level lectures, then two more of experimental work on several beamlines of the National Synchrotron Light Source, for about 50 students. Students are invited to bring their own research projects for measurement, and about half of them do. The students frequently solve half a dozen structures during the course. Tutorials by the lecturers run throughout the data-collection period. The crystal-preparation laboratory is popular for tutorials and practice, and often there is a beamline available for practice. This article provides details about the organization of the course and tells some of the reasons for its success.

[en] A survey and analysis of Protein Data Bank (PDB) depositions from international synchrotron radiation facilities, based on the latest released PDB entries, are reported. The results (< http://asdp.bnl.gov/asda/Libraries/>) show that worldwide, every year since 1999, more than 50% of the deposited X-ray structures have used synchrotron facilities, reaching 75% by 2003. In this web-based database, all PDB entries among individual synchrotron beamlines are archived, synchronized with the weekly PDB release. Statistics regarding the quality of experimental data and the refined model for all structures are presented, and these are analysed to reflect the impact of synchrotron sources. The results confirm the common impression that synchrotron sources extend the size of structures that can be solved with equivalent or better quality than home sources

No abstract available

[en] The most recent surge of innovations that have simplified and streamlined the process of determining macromolecular structures by crystallography owes much to the efforts of the structural genomics community. However, this was only the last step in a long evolution that saw the metamorphosis of crystallography from an heroic effort that involved years of dedication and skill into a straightforward measurement that is occasionally almost trivial. Many of the steps in this remarkable odyssey involved reducing the physical labor that is demanded of experimenters in the field. Other steps reduced the technical expertise required for conducting those experiments.

[en] This work examined the impact of substituting FeCrAl cladding on a single PWR fuel rod and a single fuel assembly within a full core environment of standard Zircaloy cladded fuel. The goal was to provide insight on a pin-by-pin level of the power peaking effects caused by heterogeneity in the lattice, as well as to investigate some of the key fuel performance parameters. The neutronic analyses herein reported were performed using CASMO- 4/Simulate-3 models of a representative equilibrium PWR core with standard Westinghouse 17 x 17 assemblies, while the fuel performance analysis was performed using the Bison code with FeCrAl constitutive models currently under development at the University of Tennessee in collaboration with Oak Ridge National Laboratory. (Author)

[en] We present the current status of development of the two macromolecular crystallography (MX) beamlines, FMX and AMX, and the X-ray scattering beamline LIX, at the National Synchrotron Light Source-II (NSLS-II) [1]. Together, FMX and AMX will cover a broad range of use cases from serial crystallography on micron sized crystals, to very large unit cell complexes, to rapid sample screening, e.g. for the always-hard-to-grow membrane proteins and for ligand binding studies. The LIX beamline will support a variety of X-ray scattering measurements for studies on proteins in solution, lipid membranes and biological tissues. We have performed Synchrotron Radiation Workshop (SRW) [2] and Shadow[3] simulations to help select optimal methods to modify the size of the beam easily and smoothly at both FMX and AMX. The very low emittance of the NSLS-II storage ring and the resulting low divergence of the X-ray beam, as well as the long optical path lengths in the photon delivery systems lead to stringent requirements e.g. for vibrational stability and mirror quality. We discuss beamline design considerations addressing these challenges, such as combining mirror optics with compound refractive lenses (CRLs).

[en] We report on the status of the development of three beamlines for the National Synchrotron Light Source-II (NSLS-II), two for macromolecular crystallography (MX), and one for wide- and small-angle x-ray scattering (SAXS). Funded by the National Institutes of Health, this suite of Advanced Beamlines for Biological Investigations with X-rays (ABBIX) is scheduled to begin operation by 2015. The two MX beamlines share a sector with identical canted in-vacuum undulators (IVU21). The microfocusing FMX beamline on the inboard branch employs a two-stage horizontal source demagnification scheme, will cover an energy range of 5 – 23 keV, and at 12.7 keV will focus a flux of up to 10¹³ ph/s into a spot of 1 μm width. The companion AMX beamline on the short outboard branch of the sector is tunable in the range of 5 – 18 keV and has a native focus of 4 μm (h) × 2 μm (v). This robust beamline will be highly automated, have high throughput capabilities, and with larger beams and low divergence will be well suited for structure determinations on large complexes. The high brightness SAXS beamline, LIX, will provide multiple dynamic and static experimental systems to support scientific programs in solution scattering, membrane structure determination, and tissue imaging. It will occupy a different sector, equipped with a single in-vacuum undulator (IVU23). It can produce beams as small as 1 μm across, and with a broad energy range of 2.1 – 18 keV it will support anomalous SAXS.

[en] SiC/SiC composites are candidates for accident tolerant fuel cladding in light water reactors. In the extreme nuclear reactor environment, SiC-based fuel cladding will be exposed to neutron damage, significant heat flux, and a corrosive environment. To ensure reliable and safe operation of accident tolerant fuel cladding concepts such as SiC-based materials, it is important to assess thermo-mechanical performance under in-reactor conditions including irradiation and realistic temperature distributions. The effect of non-uniform dimensional changes caused by neutron irradiation with spatially varying temperatures, along with the closing of the fuel–cladding gap, on the stress development in the cladding over the course of irradiation were evaluated. The effect of non-uniform circumferential power profile in the fuel rod on the mechanical performance of the cladding is also evaluated. These analyses have been performed using the BISON fuel performance modeling code and the commercial finite element analysis code Abaqus. A constitutive model is constructed and solved numerically to predict the stress distribution in the cladding under normal operating conditions. The dependence of dimensions and thermophysical properties on irradiation dose and temperature has been incorporated into the models. Initial scoping results from parametric analyses provide time varying stress distributions in the cladding as well as the interaction of fuel rod with the cladding under different conditions of initial fuel rod-cladding gap and linear heat rate. It is found that a non-uniform circumferential power profile in the fuel rod may cause significant lateral bowing in the cladding, and motivates further analysis and evaluation.