Applications are invited for a Postdoctoral Research Assistant at the John Adams Institute: High-Energy Beam Dynamics.
The post is available initially for fixed-term duration of 24 months with the possibility of 12 months extension.
The John Adams Institute for Accelerator Science, Oxford, is seeking a Postdoctoral Research Assistant to lead an investigation into high-intensity particle beam dynamics as relevant for hadron collider synchrotrons at the high-energy frontier, such as the Large Hadron Collider (LHC) and its High Luminosity upgrade (HL-LHC) at CERN, the European Laboratory for Particle Physics (Geneva, Switzerland). The studies as part of the Oxford team are carried out in close collaboration with the CERN Accelerator and Beam Physics Group, and the postholder will have the opportunity to take an active role in designing and carrying out dedicated experiments at the LHC accelerator complex.
This research project addresses a key question which every hadron collider design needs to face, namely achieving beam stability with minimal impact on beam lifetime. Detrimental coherent beam instabilities such as, e.g., the slow head-tail or electron cloud instability, are typically mitigated with schemes involving Landau octupole magnets. Their nonlinear fields induce a tune spread, which provides Landau damping at the expense of reducing the dynamic aperture. This in turn can lead to slow beam loss and a correspondingly reduced beam lifetime, which detrimentally affects luminosity production for the physics experiments.
The HL-LHC is designed to deliver a tenfold increase of integrated luminosity for the main LHC experiments, which is partly achieved with beams of twice the number of particles per bunch. This ultra-high beam intensity demands special attention to mitigate the risk of correspondingly stronger collective beam instabilities. The LHC beam stabilisation scheme relies critically on Landau octupole magnets. Operating the collider requires a careful balance between maintaining beam stability and avoiding a reduction in beam lifetime due to limited dynamic aperture. Past experience has shown that, under certain circumstances, the Landau octupoles needed to be powered at maximum available currents to stabilise the beams. Likewise, the dynamic aperture is particularly sensitive to magnetic field imperfections of the main magnets in the collider’s interaction regions. The bench-measured field quality of the new HL-LHC magnets is now available and the associated potential lifetime deterioration must be assessed and mitigated. This research project aims to contribute to understanding the associated beam dynamics, propose mitigation strategies and explore alternative ideas.
The successful candidate will develop innovative solutions to address the challenge of maximising beam lifetime while ensuring beam stability. The study will involve computational modelling of dynamic aperture and coherent instabilities based on single- and multi-particle tracking simulations, as well as designing and conducting experiments at the CERN accelerator complex, followed by corresponding data analysis. The outcomes of this work are expected to support the HL-LHC Upgrade by identifying possible improvements in dynamic aperture, for example through optics modifications, magnet sorting, and similar. The project will play a key role in exploring alternative stabilisation schemes to Landau octupoles with relevance for future collider designs. The successful candidate will take a leading role, as appropriate, in the publication and presentation of results. The post-holder will have the opportunity to teach. This may include lecturing, small group teaching, and tutoring of undergraduates and graduate students.
Applicants should hold or be close to completion of a PhD/DPhil in accelerator physics, particle physics, or a closely-related discipline. Demonstrated experience, knowledge, and interest in accelerator technologies is essential. Applicants should have a proven track record of high-quality research at large-scale accelerator infrastructures. A solid background in beam dynamics in synchrotrons and the corresponding numerical modelling is required. Applicants should have the ability to identify research objectives and subsequently conceive, plan and independently execute appropriate activities to deadlines. It will be important to Communicate effectively, both orally and in writing. Ability to find information, analyse complex data and represent this in an accessible form is essential.
Experience in the following area would be an advantage but is not required:
The closing date for applications is 12 noon on Wednesday, 3 December 2025. Applications for this vacancy are to be made online. You will be required to upload a CV and supporting statement as part of your online application.
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