An injector generates electrons from a cathode (metallic, semiconducting or based on carbon nanotubes) via photoemission, thermionic or field emission. A high-intensity electron injector for a linear accelerator reaches relatively lower energies where the direct space charge regime is still dominant. The cavity provides rapid extraction from the vicinity of the cathode while the solenoidal magnetic field provides compensation for this space charge defocusing and coupling the beam envelope to the subsequent accelerator stages and compensating for space charge defocusing. The design of this optical matching section is crucial for the following linear accelerator that boosts the energy of the particles up to tens of MeV from a few MeV achieved at the exit of the gun. Traditional space charge compensation with solenoids provides a linear focusing force leaving characteristic nonlinear tails in the transverse phase space distribution of the beam.
The PhD student will perform analytical and numerical work on a new hybrid gun design providing an accelerating transverse magnetic mode and a focusing transverse electric mode in subsequent cells to remove the residual non-linear tails in phase space after space charge compensation. This will demonstrate the reduction of emittance down to RF-limited values (assuming photoemission hence low thermal emittance). The student will work closely with the RF experts at Lancaster University within the Cockcroft Institute and perform beam dynamics simulations using the existing C++-based code OPAL. These simulations will be a part of an iterative design process for the structures. They will also have the flexibility to get involved in the design of these novel structures and perform CST simulations. The analytical aspect of this project will focus on the theory of space charge force and its decomposition to higher-order components. This will unveil the nature of the space charge forces and guide the design of the RF structure. The analysis of the data will be performed using ideally Python or Matlab or similar a postprocessing tool.
The results of this study will generate key input for UK XFEL injector design which recently entered the Conceptual Design phase as well as provide indications for future upgrades of AWAKE electron injector and research and development in our local FEL test facility CLARA.
You will be encouraged to actively influence the direction of your research during the course of this project in achieving the following key goals:
- You will train in accelerator physics by following the lecture series provided by the Cockcroft Institute. Initially, you will mainly concentrate on literature study and theory of space charge effects as well as novel work on its decomposition followed by dissemination of theoretical work.
- You will train in computational beam dynamics and RF design which is not a widely available skill set. By doing so, you will be taking a leading role in
- performing iterative simulations using the structure field maps provided by the RF team and characterising the phase space response and,
- Then, you will perform 3D electromagnetic simulations to understand and design modes induced in RF structures in collaboration with the RF team for further systematic studies.
- You will demonstrate the final design and full optimisation process and disseminate your work in the form of articles in high-impact academic journals and a PhD thesis.
The successful candidate will spend most of his/her time at the Cockcroft Institute.
Funding
At Manchester we offer a range of scholarships, studentships and awards at university, faculty and department level, to support both UK and overseas postgraduate researchers.
For more information, visit our funding page or search our funding database for specific scholarships, studentships and awards you may be eligible for.
Before you apply
We strongly recommend that you contact the supervisor(s) for this project before you apply.
How to apply
To be considered for this project you’ll need to complete a formal application through our online application portal.
When applying, you’ll need to specify the full name of this project, the name of your supervisor, details of your previous study, and names and contact details of two referees.
Your application will not be processed without all of the required documents submitted at the time of application, and we cannot accept responsibility for late or missed deadlines. Incomplete applications will not be considered.
If you have any questions about making an application, please contact our admissions team by emailing [Email Address Removed].
Equality, diversity and inclusion
Equality,diversity and inclusion is fundamental to the success of The University of Manchester and is at the heart of all of our activities. We know that diversity strengthens our research community, leading to enhanced research creativity, productivity and quality, and societal and economic impact.
We actively encourage applicants from diverse career paths and backgrounds and from all sections of the community, regardless of age, disability, ethnicity, gender, gender expression, sexual orientation and transgender status.
We also support applications from those returning from a career break or other roles. We consider offering flexible study arrangements (including part-time: 50%, 60% or 80%, depending on the project/funder).
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