A joint team of scientists from the Cornell High Energy Synchrotron Source (CHESS), King Abdullah University of Science and Technology (KAUST) in Saudi Arabia, and Stanford University just reported an experimental break-through for studying the structural evolution of organic transistor layers during the coating process in-situ and in real-time with x-ray scattering.

Organic field-effect transistors (OFETs) find multiple applications, for instance as switches in active displays, radio frequency identification tags, or flexible biomedical sensors. The mobility of an organic semiconductor film is a measure for the velocity of charge carrier transport and is reflected in the operational speed of the device. Normally, the single crystal of an organic semiconductor achieves higher mobility than a thin film by several orders of magnitude, but would be hard to implement in solution-based production processes.

The signals look much like x-ray absorption near-edge spectroscopy (XANES), but the element K-edges (E_K) are not otherwise accessible at CHESS. XRS offers possibilities for monitoring light element chemical and physical processes when soft x-rays cannot be used, for example samples at high pressure or during chemical processing. Analyzer crystals are positioned to collect and reflect scattered hard x-ray photons at energy E₁ as incident beam energy E₀ is scanned in the vicinity of E₁+ E_K.

There are four known families of membrane-immersed proteases (enzymes which break protein chains); all four carry out important functions and damage to them is implicated in pathologies including cancer, Parkinson's disease, impaired resistance to parasites, and more. When a mutation results in overactivity of a membrane protease, an inhibitor of the protease can be effective treatment for a disease. Designing such inhibitors has proven difficult, largely because of incomplete understanding of the catalytic process in the intramembrane environment.

This question was posed to several engineers at CHESS who were asked to describe in simple terms the three most important aspects of their jobs at a National Synchrotron Light-Source facility. Their responses were strikingly similar, with the ability to solve complex problems being at the top of their collective list, followed by the application of math and science knowledge to help them tackle these problems.

Cornell Mechanical & Aerospace Engineering student, Anton Volkmann, has sealed his place in the rich history of walkalong gliding.  Described as “the paper airplane that keeps on flying,” you launch one of these gliders by hand, then keep it aloft on a wave of air that you create by walking. First invented in 1950, they weren’t publicized until featured on PBS’s Scientific American Frontiers with Alan Alda in 2001. They are still little-known outside of a small, but growing group of progressive educators and aeronautic enthusiasts.

At CHESS, we have adopted this microfabrication technique to develop novel x-ray optics called,Collimating Channel Arrays  (CCAs) [1], for confocal x-ray fluorescence microscopy (CXRF). Because the first CCA optics were fabricated from silicon substrates, the range of x-ray fluorescence energies for which they could be used, and hence the elements they could be used to study, was limited. Unwanted x-rays above about 11 keV could penetrate through the silicon, showing up as background and interfering with the measurement.

CHESS staff have been hard at work since the initial installation of the shield walls in September (completed in 6 short days!). Installation of the transfer pipe from the F2 hutch, station beam stops and associated shielding, utilities, and beamline controls were completed all while servicing users during the fall CHESS running period. Monochromatic beam experiments have already begun and white beam capability will be commissioned during the 1-week spring shutdown.

One class of such novel materials, block copolymers (BCPs), are being developed today to enable continued advancement of data archiving, as well as advanced drug refinement using protein filters, among other things.

On Sept. 6, the 26-ton solenoidal superconducting magnet was carefully removed from the Wilson Synchrotron Laboratory. This was the last vestige of the CLEO detector, which for nearly 30 years recorded data produced from the collision of positively and negatively charged electrons that hurtled around the 840-yard subterranean collider, CESR (Cornell Electron-positron Storage Ring).