Measurement and correction of charged particle beam optics have been a major concern
since the advent of strong focusing synchrotron accelerators. Traditionally, particle colliders …

Optics measurements at the LHC are mainly based on turn-by-turn signal from hundreds of
beam position monitors (BPMs). Faulty BPMs produce erroneous signal causing unreliable …

Since 2015 the LHC has been operating at 6.5 TeV. In 2016 the β-functions at the interaction
points of ATLAS and CMS were squeezed to 0.4 m. This is below the design β*= 0.55 m at 7 …

Optics measurement algorithms have been improved in preparation for the commissioning
of the LHC at higher energy, ie, with an increased damage potential. Due to machine …

Amplitude detuning measurements in the LHC have shown that a significant amount of
detuning is generated via feed-down from high-order field errors in the magnets of the …

Since the first transverse instability observed in 2010, many studies have been performed on
both measurement and simulation sides and several lessons have been learned. In a …

In the past, transverse coherent instabilities have been observed at the Hadron-Electron
Ring Accelerator (HERA) proton ring that were instigated by the presence of linear coupling …

In 2017, optics commissioning strategy for low-β* operation of the CERN Large Hadron
Collider (LHC) underwent a major revision. This was prompted by a need to extend the …

Successful operation of large-scale particle accelerators depends on the precise correction
of magnet field or alignment errors present in the machine. In the Large Hadron Collider …

The observations of coherent instabilities in all operational phases of the LHC during Run 2
are summarised, describing their impact on the performance. The evolution of the mitigation …