International Workshop on Higher Order Modes in Superconducting Cavities (HOMSC2025)

Developing a Beam Spectrum for Transient Beams in the CERN Double Quarter Wave Crab Cavities

8 Oct 2025, 09:00

30m

Seminar Room IV (first floor) (CFEL (bld. 99))

Oral contribution Operation of SRF Facilities Operation of SRF Facilities

Speaker

Conor Euan Charles McFarlane (Lancaster University)

Description

As part of the High Luminosity project of the Large Hadron Collider (LHC) at CERN, transverse deflecting cavities (crab cavities) have been developed to compensate for the luminosity reduction caused by the collision crossing angle. Initial estimations of the cavity HOM power in 2018 were not in agreement with measurements of the prototype cavities when tested with beam. Advancements in modelling the beam spectrum have shown to compensate for these discrepancies (up to 20dBm). These studies have highlighted the importance of considering transient effects in beam dynamics when assessing HOM power. Additionally, it has been observed that RF-beam manipulation earlier in the CERN accelerator chain can leave harmonic resonances in the beam spectrum.