INFRARED MICROSPECTROSCOPY TO ASSESS NEURODEGENERATION

Yeshiva University, New York NY

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Abstract

The stability and reproducibility of the intensity of the dynamically focused x-ray beam from the sagittally focusing monochromator has been significantly improved. Also, data collection during scanning has been enabled by angling the trolley rail so that focus is maintained during energy scans. Increased stability was also achieved by counter balancing the massive crystal bender about its rotation axis, and thereby reducing the dispersion of the Piezo voltage with energy (the piezo keeps the first and second crystals of the double crystal monochromator aligned). New software parameters were then determined for the equation of motion for the monochromator and for the piezo calibration routine. Thus, the automatic piezo calibration software that has been used with the nonfocusing monochromator can be used with the sagittal focusing monochromator. The new software parameters also restore the constant exit height feature of the monochromator for energy ranges on the order of 1000 eV. Thus after initially focusing the beam, the dynamically focusing feature of the monochromator is transparent to the user. Computer control of the bender has also been implemented, allowing automated focusing changes during a scan.