Longitudinal Density Monitor for the Large Hadron Collider
Student: Alexander Jury
Supervisors: Hao Zhang, Carsten P Welsch (UoL), Stefano Mazzoni (CERN)
At the Large Hadron Collider (LHC), the world’s largest and highest energy particle accelerator, ion bunches circulate in two counter-rotating beams and are brought into collision. Each bunch is confined within a bucket by the longitudinal focusing effect of the radio frequency (RF) cavities. The RF period is 2.5 ns, while the minimum bunch spacing is 25 ns. Thus, 9 out of every 10 buckets should be empty, as well as additional gaps to allow for the rise-time of injection and dump kickers. In practice, however, small numbers of particles can occupy these supposedly empty buckets, causing problems for machine protection and for the absolute calibration of the LHC’s luminosity.
The Longitudinal Density Monitor (LDM) is a key diagnostic in the LHC for particle physics experiments and used to measure the profile with very good resolution. This monitor produces a vast amount of data used for luminosity calibration and machine control.
This PhD project will focus on the development of novel approaches to analyse this data and develop a novel tool for precise real-time luminosity measurements. This will include techniques to correct for bias associated with different monitor types, beam distributions and beam-beam effects. Moreover, the impact of pileup effects will be assessed and mitigation strategies will be developed.
You will have access to the Cockcroft Institute’s comprehensive postgraduate training in accelerator science, as well as to LIV.INNO’s structured training. You will spend years 1 and 4 in the UK, and be based at CERN during years 2 and 3. Whilst in the UK, a standard RCUK PhD stipend will be paid, during the time at CERN, the usual CERN doctoral student allowance will be paid.