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EVALUATION OF MASS FILTERED, TIME DILATED, TIME-OF-FLIGHT MASS SPECTROMETRY

dc.contributor.advisorMignerey, Alice Cen_US
dc.contributor.authorDemoranville, Leonard Thomasen_US
dc.date.accessioned2011-02-19T06:41:18Z
dc.date.available2011-02-19T06:41:18Z
dc.date.issued2010en_US
dc.identifier.urihttp://hdl.handle.net/1903/11114
dc.description.abstractThe Naval Research Laboratory's Trace Element Accelerator Mass Spectrometer (NRL-TEAMS) system offers a unique opportunity to develop a new type of time-of-flight (TOF) SIMS. This opportunity derives from use of a Pretzel magnet as a recombinator and mass filter in the injector to the accelerator. Mass filtering prior to time-of-flight analysis removes extraneous species, shortening the analysis time for a single beam pulse, thereby improving the duty cycle. Using this approach, it is possible to obtain an expanded portion of a narrow segment of the entire time-of-flight spectrum created by a single beam pulse. A longer flight path for greater momenta in the Pretzel magnet introduces time dilation. Potential benefits derived from time dilation and mass filtering include improved duty cycle, shorter analysis time, increased precision, and better resolution. While the NRL-TEAMS system is not designed for TOF work, it has been used as a test bed to prove the theoretical benefit of such a design. Theoretical treatments of the spectrometer have shown improved resolution is possible under certain conditions, when compared to a traditional TOF spectrometer. SIMION 8.0 computer simulations were used to model the system and provide insight to the theoretical capabilities of the Pretzel magnet. As expected, models have shown that as field decreases, and therefore path length increases, mass resolution improves. Generally, the model matched well to experimental results provided by the NRL TEAMS system. These experimental results have predicted fundamental parameters of the system accurately and consistently, and confirmed the validity of the model. This research improved the current system's performance through improved electronics and pulsing and further uses the model to predict the theoretical benefits of a system designed for use with a Pretzel magnet.en_US
dc.titleEVALUATION OF MASS FILTERED, TIME DILATED, TIME-OF-FLIGHT MASS SPECTROMETRYen_US
dc.typeDissertationen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.contributor.departmentChemistryen_US
dc.subject.pqcontrolledNuclear Chemistryen_US
dc.subject.pqcontrolledAnalytical Chemistryen_US
dc.subject.pquncontrolledMass Spectrometryen_US
dc.subject.pquncontrolledSIMSen_US
dc.subject.pquncontrolledTime-of-Flighten_US


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