The furnace is based on a design originally brought to G1 by John Hart’s group (MIT, then at University of Michigan) to study fabrication and kinetic effects in carbon nano-tube forests. The furnace uses highly doped, single-crystal silicon as the sample stage and heater. The temperature response is fast (~100C/second), accurate, and results in relatively little sample motion from thermal expansion. The furnace can be operated in air or under gas flow, and exchanging samples is straightforward and fast.
The new glovebox provides users with an air and moisture free environment to store and prepare air sensitive samples for measurement at CHESS. Currently the glovebox provides a dry nitrogen environment; however, future upgrades will allow users to select nitrogen, argon, or helium environments dependent upon experimental needs. During the fall x-ray running period the glovebox was installed and commissioned MBraun and tested by two local Cornell experimental groups.
This note describes a sequence of upgrades to CHESS and the CESR source that culminate in a 100,000-fold increase in spectral brightness and a 1000-fold increase in flux, on par with the best continuous duty hard x-ray sources world-wide. The spectral brightness and the flux through a pinhole 30m from the source for this sequence of upgrades and other leading sources are shown in the following figure.
When Lora Hine, director of educational programs at the Cornell Laboratory for Accelerator-Based Sciences and Education, asked me to co-coach a FIRST LEGO League (FLL) team this past fall, I hesitated. After all, when I was a kid, I would never have joined a robotics team. I had no interest in gadgets, technology or computer programming. I didn't even like science, which seemed to be all about memorizing facts.
It replaces the original (30 year old) CHESS 4-circle, and provides many new capabilities. This system weighs 4600 pounds together with its support table engineered by Alan Pauling, based on an APS Sector 7 design. The table was built for CHESS in New York State, by Keller Engineering in Buffalo.
RNR plays a critical role in regulating the total rate of DNA synthesis, which is necessary to maintain the constant DNA to cell mass ratio during cell division and DNA repair. The reaction is strictly conserved in all living organisms and proceeds via a free radical mechanism of action. Class Ia RNR (e. g. Escherichia coli RNR) enzymes are constructed from large RNR α2 and small RNR β2 subunits which associate to form an active heterodimeric tetramer: an α2β2 complex.
The "PiXirad-1" module mounts easily on the 4-circle diffractometer at the A2 endstation, and is fully integrated into SPEC control. First-ever synchrotron tests and user experiments using the PiXirad were performed at CHESS during 2013. The defining advantage of this unit is the use of a CdTe crystal sensor instead of Si, which gives the PiXirad very high detection efficiency (> 90%) for photons with energies greater than 50 keV.
The G1 beamline control area has been renovated and reorganized to make more efficient use of space and to accommodate larger groups. The G-line chem room, which has 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.
In addition to the ability to generate 3D reconstructions of the sample in question via optical sectioning, confocal microscopy can also be used to measure reaction kinetics in the fluorescence mode.
The paper must be based in part on data collected at the Cornell High Energy Synchrotron Source, and the first author on the paper must have been a graduate or undergraduate student when the paper was submitted. (In certain circumstances, two submissions may be selected as winners, in which case the award will be shared.)