Adaptation of the PROBE Cavity Design for Linear Proton Therapy Accelerators

During the previous successful PROBE grant the Cockcroft Institute designed and manufactured a 3 GHz side-coupled structure suitable for boosting the energy of a clinical cyclotron proton beam from 250 MeV upwards. The PROBE structure is predicted to deliver a world-leading gradient greater than 50 MV/m, and uses a patented method of construction that allows effective interior shaping of the cavity.

A high-gradient 3 GHz cavity is also of interest when used in a linac-based proton therapy system. The inherently smaller linac emittance would allow a smaller iris aperture and this could deliver a larger gradient using the same methods already demonstrated on PROBE in a previous PhD project - potentially over 60 MV/m. However, such a cavity has not yet been designed. This PhD project would carry out the detailed design of such a cavity in partnership with an interested industrial partner. We would construct a prototype using separate funding.

We have already carried out the equivalent design and manufacture of a previous cavity, so we are confident we know the challenges and pitfalls and have learnt a great deal from the previous project. We therefore judge the project has a high likelihood of obtaining a successful outcome. We can also confidently plan for the work of the PhD.