Search

The betatron tune in the Large Hadron Collider (LHC) is measured using a Base-Band-Tune (BBQ) system. Processing of these BBQ signals is often perturbed by 50Hz noise harmonics present in the beam. This causes the tune measurement algorithm, currently based on peak detection, to provide incorrect tune estimates during the acceleration cycle with values that clearly oscillate between neighbouring harmonics. The LHC tune feedback cannot be used to its full extent in these conditions as it relies on stable and reliable tune estimates. In this work we present two alternative tune measurement algorithms, designed to mitigate this problem by ignoring small frequency bands around the 50Hz harmonics and estimating the tune from spectra with gaps. One is based on Gaussian Processes and the other is based on a weighted moving average. We compare the tune estimates of the new and present algorithms and put forward a proposal that can be implemented during the renovation of the BBQ system for the next physics run of the LHC., Proceedings of the 9th International Beam Instrumentation Conference, IBIC2020, Santos, Brazil

The LHC Schottky monitors have the potential to measure and monitor some important beam parameters, tune, momentum spread, chromaticity and emittance, in a non-invasive way. We present recent upgrade and improvement efforts of the transverse LHC Schottky systems operating at 4.8 GHz. This includes optimization of the slotted waveguide pickups and a re-design of the RF front-end electronics to detect the weak, incoherent Schottky signals in presence of large, coherent beam harmonics., Proceedings of the 5th Int. Beam Instrumentation Conf., IBIC2016, Barcelona, Spain