LHC MD 232: Longitudinal Impedance Evaluation

The aim of the MDstudies presented here was to evaluate the imaginary part of the longitudinal impedance of the LHC by means of synchrotron frequency shift measurements. Single bunches with similar longitudinal emittance but different intensities were studied at flat top. Based on the beam parameters, a maximum shift of about 0.2 Hz was expected between the different bunches. A detailed analysis still needs to be carried out to determine the measured synchrotron frequency shift. The measurements took place between 8:00 p.m. on 26th and 2:00 a.m. on 27th July 2016