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TY - UNPB AU - Podobedov, B. ED - Yamazaki, Yoshishige ED - Raubenheimer, Tor ED - McCausey, Amy ED - Schaa, Volker RW TI - Beam Dynamics Measurements with New Generation BPMs J2 - Proc. of NAPAC2019, Lansing, MI, USA, 01-06 September 2019 CY - Lansing, MI, USA T2 - North American Particle Accelerator Conference T3 - 4 LA - english AB - Due to state-of-the-art NSLS-II beam position monitors, combined with advanced signal-processing techniques, we are now able to measure the difference between the betatron tunes of two (or more) bunches stored in the ring with the accuracy better than 10⁻⁶. For bunches of unequal charge this allows us to precisely determine the transverse kick factors. By applying local bumps, or, for in-vacuum undulators (IVUs), by varying the gap, we can also precisely measure the impedance of individual ring components. Since the tunes of unequally charged bunches are measured simultaneously, this reference method is virtually immune to machine drifts, as well as other systematic errors. For instance, in our IVU measurements vs. undulator gap, we can accurately determine current-dependent tuneshifts two orders of magnitude smaller than the tuneshift induced by the natural focusing of the undulator. Other examples of measurements performed with similar, or related, techniques include single-shot measurements of tune-shift with amplitude as well as non-invasive lattice characterization during user operations. PB - JACoW Publishing CP - Geneva, Switzerland ER -