Particle Physics, Department of Physics, Denys Wilkinson Building, Keble Road, Oxford, OX1 3RH Applications are invited for a postdoctoral research assistant focussing on the development of the vertex detector for LHCb Upgrade II. The post is available for a fixed-term duration of 12 months starting as soon as possible. The location of work can be Oxford or CERN. To develop the design and the technology of the vertex detector for LHCb Upgrade II through the TDR phase. The successful candidate will have three responsibilities: - (1) studies of composite materials for a beam-facing RF shield.(2) contributions to the operation and exploitation of the Timepix4 testbeam.(3) simulation work optimising the performance of the vertex detector design for LHCb Upgrade II. Physics analysis is possible, if time allows. Applicants should hold, or be close to completing, a doctoral degree in experimental particle physics. Previous experience of LHCb simulation development, testbeam operations or detector commissioning would be advantageous. Candidates are expected to demonstrate the ability to plan and execute research activities, communicate effectively, and work in a team. Depending on interest, the post-holder may have opportunities to teach in a College or demonstrate in the undergraduate laboratories.