RF Power Systems and Optimized RF structures for electron beam acceleration

The proposed work is driven by the ultimate goal to design a modular linear accelerator for cancer treatment with minimum subsystems making it robust, reliable and accessible to communities with lower and intermidiate incomes. The road map to achieve this goal was identified during the recent workshop hosted by STFC, CERN and ICEC in partnership with representatives from ODA countries. It is based on the idea to use the best available in accelerator science solutions and adapt them to specific problems linked to the challenging environments, financial situations and knowledge availability in the ODA countries. This project aims to design accelerating structures which can be affordable, robust, efficient and easy to look after, while keeping the design at the cutting edge of the technological solutions available. To achieve the goals the design of the RF accelerating structure will be based on the CLIC system and adapted to the 1.3GHz frequency enabling the use of either a low voltage solid state RF power supply or alternative sources like klystron or magnetron. To make it modular with minimum subsystems required the structure will be vacuum sealed i.e.no vacuum pumps will be needed to maintain the vacuum and LINAC operation. This will reduce the overall capital and maintenance cost. To reduce the manufacturing cost of the cavity a new technology of cavity manufacturing will be tested. The cavity will be machined from two aluminium blocks using CNC lathe. This will also reduce the weight of the cavity allowing the beam energy of 6MeV -8MeV to be achieved while RF cavity length is around 30cm.
The Department of Physics workshop has experience of building a 1.3GHz RF cavity using CNC lathe and will be able to manufacture the cavity in the time scale of the project. It also has experience with vacuum testing of the structures and has the equipment required. The RF bead pull test facilities (JAI Oxford and Daresbury Laboratory) will be used to measure operating and high order modes. The cavity will be sealed and vacuum tested in JAI Oxford and transported to CERN for high power RF tests. The cavity will be kept sealed to observe whether any vacuum degradation will take place with time. To ensure that the system is suitable for ODA countries the partners from Nigeria and Tanzania will be invited to the workshop in Oxford to test the system and advise on ergonomics of the design. We plan to communicate regularly (every two weeks) with all partners via web-meetings during the project to ensure stable and continuous progress as well as securing the impact of the deliverables to the overall aim of the project.

Radiation therapy is an essential for effective control and treatment of cancer, and approximately half of all cancer patients world-wide are benefiting from such treatment. The majority of modern radiotherapy facilities (developed by mainly two private companies) rely on linear accelerators (LINACs) to accelerate electrons, which are either used directly to treat superficial tumours or are directed at high density targets such as tungsten to produce X-rays for treating deep-seated tumour. Limiting factors to the development and implementation of radiotherapy in lower-resourced nations include the cost of equipment and infrastructure, and the shortage of trained personnel to properly calibrate and maintain the equipment and to deliver high quality treatment. In September 2015, the Global Task Force on Radiotherapy for Cancer Control (GTFRCC) released a comprehensive study of the global demand for radiation therapy. The GTFRCC report estimated that more than 12,000 megavolt-class medical LINACs will be needed to meet demands in Low and Medium Income Countries by 2035.
The proposed work is driven by the ultimate goal to design a modular linear accelerator for cancer treatment with minimum subsystems making it robust, reliable, cost effective and accessible to communities with lower and medium incomes. This project aims to design accelerating structures which can be affordable, robust, efficient and easy to look after, while keeping the design at the cutting edge of the technological solutions available. The outcome of the project should evaluate the possibility of significant reduction of the production and maintanace cost of LINACs for cancer treatment using radiation therapy. It will potentialy reduce the demand for a number of highgly qaulified support personal leading to machine easy to maintain and operate.