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Wednesday, July 8, 2009

Alex Silbergleit

Senior Research Scientist, Gravity Probe B,

Polhode Motion, Trapped Flux, and the GP-B Science Data Analysis

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Abstract: Magnetic field trapped in the Gravity Probe B gyroscope rotors contributes to the scale factor of the science readout signal. This contribution is modulated by the rotor's polhode motion. In orbit, polhode period was observed to change due to a small energy dissipation, which significantly complicates data analysis. We present precise values of spin phase, spin down rate, polhode phase and angle, and scale factor variations obtained from the data by Trapped Flux Mapping. This method finds the (unique) trapped field distribution and rotor motion by fitting a theoretical model to the harmonics of high (gyroscope spin) frequency signal. The results are crucial for accurately determining the gyroscope relativistic drift rate from the science signal.

Bio: Alex Silbergleit received his MS in Physics from Leningrad Polytechnic Institute (currently St.Petersburg Technical University, St.Petersburg, Russia). He then joined the staff of the A.F. Ioffe Physics-Technical Institute, Russian Academy of Sciences, where he had started research as an undergarduate student. There, in the Laboratory of Mathematical Physics, Alex held various positions, starting with Junior Scientist and ending as the Lab Director.He received the degrees of Candidate of Science (PhD equivalent) and Doctor of Science (highest Russian scientific degree), both from Ioffe Institute, and both in Theoretical and Mathematical Physics. Alex has been a member of thet Gravity Probe B team since 1994, where he has focused mostly on error and data analysis. During the GP-B flight mission, he was responsible for the express analysis of the telescope signal (pointing). During this period, he also worked with R.V. Wagoner on the theory of accretion discs of black holes and neutron stars.


Time: 4:00pm – 5:30pm

Location: Physics and Astrophysics Conference Room 102/103

Light refreshments available 4:15pm; Presentation begiins 4:15pm.

Open to All