The next generation of security linacs will likely operate with shorter pulses and higher repetition frequencies to improve material separation, single photon counting or to enable backscattered X-rays to be employed. However no such commercial linac exists already, however by utilising RF design methodology and techniques employed in high gradient accelerators and utilising existing alternative RF sources such a linac could be realised. A crucial technology that will enable short pulse operation will be the incorporation of a gridded thermionic cathode electron gun to modulate the electron beam. This project aims to design and model a thermionic cathode gridded electron gun for the RF linac. The gridded electron gun design will be developed by the University of Strathclyde in collaboration with TMD Technologies Ltd who have a track record of providing similar electron beam sources for high power microwave amplifiers. The student will take a six month placement with TMDs Technologies Ltd, Hayes Middlesex to incorporate in the design knowledge and understanding of the grid structure to enable high duty cycle operation while minimising beam interception. TMD Technologies Ltd will also make available to the student expertise of high voltage power supplies and isolation needed to apply voltage to the grid to modulate the beam. In addition the student would be involved in upgrading and running the Cockcroft Institute's existing RF linac facility to test the latest X-ray detector developments and to understand the requirements of any new linacs.