Probing the LHC impedance with single bunches

The main purpose of this MD was to study longitudinal and transverse beam dynamics in the LHC. Eight bunches with different bunch lengths and intensities were injected into the LHC in two fills. The distance between bunches is large enough so they can be treated as single bunches. The bunch length and the intensity were adjusted in the SPS by applying controlled longitudinal emittance blow-up with different amplitudes and transverse scraping. The aim of the first fill was to measure the longitudinal and the transverse impedance at injection energy (450 GeV). The second fill of the MD included acceleration to 4 TeV and was used to study the loss of Landau damping during the ramp, observed as dipole and quadrupole oscillations, and to measure the impedance at top energy. Measurements of synchronous phase shift and peak-detected Schottky spectra were taken during both fills in order to estimate the longitudinal impedance and they are presented in this Note. We also show the transverse emittance evolution during both fills and the transverse tune shifts that were measured after the beam was kicked to estimate the transverse impedance.