Supervisor: Dr Javier Resta-Lopez (Liverpool University), Prof Steve Jamison (Lancaster University), Prof Carsten Welsch (Liverpool University), Dr Guoxing Xia (University of Manchester).
Standard radiofrequency (RF) accelerator technology is limited to gradients of the order of 100 MV/m. For instance, future linear electron/positron colliders based on RF technology, such as the International Linear Collider (ILC) or the Compact Linear Collider (CLIC), are designed to produce acceleration gradients of between 30 MV/m (ILC) and 150 MV/m (CLIC, 30 GHz frequency operation mode). There machine must therefore be tens of kilometres long to reach the desires beam energies, 125 GeV (ILC) and 1.5 TeV (CLIC).
R&D into novel acceleration techniques towards more compact machines has made tremendous progress in recent years. For example, plasma wakefield acceleration (PWFA) techniques based on gaseous plasma have shown to be able to obtain gradients up to approximately 100 GV/m. On the other hand, solid-state based structures may allow us to go even beyond this limit and obtain ultra- high gradients on the order of 1-10 TV/m.
Solid-state plasma wakefield acceleration using crystals was proposed in the 1980’s and 1990’s by T. Tajima and others as an alternative particle acceleration technique to obtain TV/m acceleration gradients. However, it has not been experimentally demonstrated yet. In recent years, new efforts have been focused on the feasibility study of channelling acceleration of particle beams using carbon-based nano-crystals such as carbon-nanotubes (CNT) or metallic nanotube structures, e.g. porous alumina. CNT configurations may be advantageous over typical crystal media like silicon because of their large degree of dimensional flexibility and thermo- mechanical strength, which could be suitable for channelling acceleration of MW beams. For example, CNTs allow transverse acceptances of the order of up to 100 nm, i.e. three orders of magnitude higher than a typical silicon channel. Therefore, CNTs might be used for wakefield acceleration using either a beam or a laser as driving source.
This project proposes to investigate in detail the use of CNTs for channelling acceleration and its potential application to build more compact accelerators and X-ray radiation sources. It is based on earlier studies done by the supervisory team. This includes the design and performance of a proof-of-principle test wakefield particle acceleration in CNT arrays. Measurements will be done at different accelerator facilities, including VELA/CLARA at Daresbury, the SwissFEL at PSI, and CLEAR at CERN. These machines operate in a similar range of beam energy of approximately 200 MeV. In all cases we expect to operate with short bunches on the order of 0.1 ps, and the beam can be modulated by a bunch compressor chicane. If necessary, even shorter bunches could be obtained at the sub-fs level via bunch slicing in the magnetic chicane, using a collimator. The theoretical and simulations results will guide the design of the experimental studies.
The successful candidate will have or expect to obtain a first or upper second-class degree or equivalent (e.g. MPhys, MSci) in physics or chemistry. Experience of accelerator physics, Particle-In-Cell (PIC) programming and solid-state physics is an asset.
You will be based at the Cockcroft Institute, which is the UK’s largest educator of accelerator science and technology PhD students, and offers exciting studentships in physics, engineering and other disciplines.
Potential applicants are encouraged to contact Prof. Carsten P. Welsch ([email protected]
) or Dr. Javier Resta-Lopez ([email protected]
) for more information. This position will remain open until filled.
Funding and eligibility: Upon acceptance of a student, this project will be funded by the Science and Technology Facilities Council for 3.5 years; UK and other EU citizens are eligible to apply. A full package of training and support will be provided by the Cockcroft Institute, and the student will take part in a vibrant accelerator research and education community of over 150 people. An IELTS score of at least 6.5 is required.
How to apply: http://www.cockcroft.ac.uk/join-us
Anticipated Start Date: October 2019 for 3.5 Years