Kramer, F.; Goslawski, P.; Hwang, J.G.; Kuske, P.; Ruprecht, M.; Schälicke, A.: Simulations and Measurements of the BPM Non Linearity and Kicker Timing Influence on the Tune Shift With Amplitude (TSWA) Measurement at BESSY II. In: Shane Koscielniak ... [Ed.] : IPAC2018 : Proceedings of the 9th International Particle Accelerator Conference, Vancouver, BC, CanadaJACoW, 2018. - ISBN 978-3-95450-184-7, p. WEPAK010
http://accelconf.web.cern.ch/AccelConf/ipac2018/papers/wepak010.pdf
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Abstract:
The Tune Shift With Amplitude (TSWA) does not only determine the position of the stable Ąx points for the Transverse Resonant Island Buckets (TRIBs) [1Ű4] but also represents a global observable for the nonlinear optics in general. For theoretical investigations of the TRIBs a reliable nonlinear optics of the machine is required and thus all measurable global observables for the nonlinear optics are of great interest. The measurement of the TSWA [2] for the BESSY II standard optics was performed using an injection kicker to excite high amplitude betatron oscillations and then extract the amplitude dependant frequency from the synchrotron radiation damped oscillation with a Hilbert transformation. With TRIBs optics the injection kicker was not able to suicienty excite the beam. The impact and correctability of the BPM nonlinearity at the reached amplitudes and the reason for the failure of the excitation method for our TRIBs optics shall be looked onto in this paper.