Technical Summary: Replacing the current single-pole wavelength shifter with a multipole wiggler will increase the X-ray flux by about 10 fold and extend the range of useful intensities to higher energies. The wiggler will serve 4 beamlines on the CAMD synchrotron and will greatly benefit researchers in the following fields. Protein Crystallography: The higher brightness will allow studies involving smaller crys-tals and/or higher resolution data sets, both requiring intensity levels currently unavailable. Re-duced data collection times will increase the productivity of the beamline. Tomography: The increased transverse beam coherence of the MPW, estimated at 0.2 µm, will enable new full-field phase contrast imaging, a powerful method of enhancing image contrast in samples. Also, the increased flux will enable practical high resolution tomography, about 3 µm, for large field-of-view samples. Medical Radiology: Current research is aimed at a potentially new radiation therapy called K-edge capture therapy in which the dose is localized by means of a drug that targets can-cer cells. Dual energy K-edge imaging and phase contrast imaging have significant potential in diagnostic imaging, including breast cancer screening. The increased intensity and energy of X-rays will allow studies to be extended to Gd and other high-Z contrast agents. X-ray Spectroscopy: The 10 to 14-fold greater X-ray flux in the range of 4 to 24 keV will improve signal-to-noise ratio in XANES and EXAFS and will permit experiments that include in-situ catalyst studies, environmental studies of dilute metal pollutants and of metal sites in in-tact proteins. The K or L edges of almost all transition metals will be accessible. Microfabrication: Higher energy photons from the MPW will improve the fabrication of high aspect ratio microstructures, a unique advantage of X-ray lithography.
Lay Summary: The photons produced by the proposed multipole wiggler are called ?hard X-rays?. They have wavelengths comparable to the distance between atoms and can pass through matter without causing significant damage. This unique combination of properties makes hard X-rays ideal for determining the structure of crystallized molecules, including very large mole-cules such as proteins, and for investigating the internal structures of solids. X-ray based struc-ture determination is an essential part of modern drug discovery. Other applications for hard X-rays exploit the fact that each element absorbs X-rays at certain wavelengths characteristic of that element. By selecting an appropriate wavelength, re-searchers can investigate the chemical state of individual atoms in a molecule. This is an impor-tant tool in studies of environmental contamination. The same property may be used to enhance the effectiveness of radiation therapy by localizing the radiation dose to regions labeled with tu-mor-specific drugs. All of these applications require an intense source of X-rays that can produce radiation of the desired wavelengths. Synchrotron rings can be strong sources of X-rays when the electron beam inside the ring is passed through a magnetic field. We are proposing to install a set of 11 very strong superconducting magnets on the existing synchrotron at Louisiana State University. This device, known as a Mulitpole Wiggler, will increase the intensity of the X-rays available to experimenters by more than 10 fold and the high-intensity output will extend over a wide range of wavelengths. All of the applications mentioned above will benefit greatly from the new mul-tipole wiggler.
