Ultrashort bunch length characterisation based on Cherenkov diffraction radiation (ChDR) for AWAKE Run 2c/d

About the project

About the Project Academic School: Physics and Astronomy, University of Manchester Anticipated Start Date: October 2026 for 3.5 Years Supervisor Team: Guoxing Xia (University of Manchester, guoxing.xia@manchester.ac.uk ) Carsten Welsch (University of Liverpool, welsch@liverpool.ac.uk ) Pavel Karataev (Royal Holloway University of London, pavel.karataev@rhul.ac.uk ) Can Davut (TENMAK, Ankara, Turkey, can.davut@tenmak.gov.tr ) Thibaut Lefevre (CERN, Thibaut.Lefevre@cern.ch ) Project description AWAKE (Advanced WAKefield Experiment) is the world only proton-driven plasma wakefield acceleration experiment. It utilizes 400 GeV proton bunch from the CERN SPS as drive beam, excites a plasma wakefield with the amplitude of ~ GV/m and accelerates an externally injected electron bunch to high energy. The AWAKE Run 1 (2016-2018) has successfully demonstrated the seeded self-modulation (SSM) for a long proton bunch and the electron acceleration up to 2 GeV in a 10 m-long plasma. The AWAKE Run 2a/b (2021-2025) has achieved for the first time the electron seeding proton-driven wakefield and the sustained high amplitude wakefield with a plasma density step. Given the great success of AWAKE Run 1 and Run 2a/b, the upcoming phase of the AWAKE experiment, so-called Run 2c/d (2029-2033), aims to achieve high-quality (emittance, energy spread and charge preserved), high energy (up to 5-10 GeV) electron beam in two plasma cells, with the first one for proton modulator and the second one for electron accelerator. The technology to be demonstrated will have a significant impact to the particle physics applications based on AWAKE scheme. The success of the AWAKE Run 2c/d will largely rely on the precise characterisation of the electron beams. Among them, the electron bunch length information is crucial as it affects the final beam quality. To achieve the goals of AWAKE Run 2c/d, two electron injectors will be used, with the one providing a 20 MeV beam for seeding the instability in the first plasma cell and the second one having ~200 fs bunch duration with beam energy of 150 MeV and serving as the witness beam to sample the wakefield generated in the second plasma cell. We are currently collaborating with colleagues from CERN, Liverpool, RHUL and TENMAK to develop a novel bunch length monitor based on Cherenkov diffraction radiation (ChDR). In this PhD project, the student will be leading this initiative and simulate the radiation spectra based on the current setup. Additionally, they will model the betatron radiation spectra from both the seeding and the witness electron bunches. The further test will be performed at CLEAR and CLARA to gain more insights on this bunch length monitor, with the aim to install and operate them into the AWAKE Run 2c/d beamline. Qualifications applicants should have/expect to receive: The successful candidate will spend at least 1 year at CERN to perform the experimental test. The successful candidate will have or expect to obtain a first or upper second-class degree or equivalent (e.g. MPhys, MSci) in physics. Experience of accelerator physics and computational physics is desirable but not essential. Funding and eligibility: The project is fully funded by the Cockcroft Institute for 3.5 years. A full package of training and support will be provided by the Cockcroft Institute and the University of Manchester. Self-funded overseas students may apply. An IELTS score of at least 6.5 is required. Contact for further information: guoxing.xia@manchester.ac.uk , or visit Room 3A.11, Schuster Building (Annexe) on the University of Manchester main campus. How to apply: Please apply via the Cockcroft Institute webpage . For full consideration for funding please apply by 31st Jan 2026.

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