MAJOR UPGRADE OF THE X/KU BAND SPECTROMETER

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Our 10-years old 2D-FT-ESR and DQC/DEER spectrometer has undergone several modifications over its life-time. It has been in very intense use and has also served as a testing ground for new concepts and applications. Due to aged components, some of which were bought used, failures have became more frequent and it lacks useful automation and other important features. For its continuous intense use it should be totally renovated to meet our new higher standards. What we plan to do is thus a radical upgrade, to make of it a versatile automated machine that is intuitive for a new user. This overhaul will encompass as a minimum: (a) adding a new field controller; (b) writing a new LabView software interface, (c) replacing the old heterodyne bridge with a new one that will have two main channels, a DEER channel, and a TPPI channel; (d) adding a new probe based on a dielectric resonator with a uniform field; (e) installing a programmable attenuator; (f) adding a software programmable receiver gain and phase; (g) implementing spectrometer protect electronics; (h) achieving more versatile control over signal acquisition; (i) upgrading with MESFET based nanosecond low-transient switches; (j) adding field-frequency lock. We plan to make these upgrade with low down-time when all new elements are in place and thoroughly bench-tested.