Letter of Intent for a Demonstration Experiment in Proton-Driven Plasma Wakefield Acceleration

We propose an experiment on proton-driven plasma wakefield acceleration (PDPWA) which could lead to a future TeV-scale e+- collider of much reduced length compared to conventional designs. Proton bunches are ideal drivers for high energy lepton accelerators, with the potential of reducing drastically the number of required driver stages. By using a plasma to modulate a long proton bunch, a strong plasma wave can be generated by a series of ‘micro-bunches’, so that an experimental program can start today with the existing proton beams. In this letter of intent, we propose a demonstration experiment using the existing CERN SPS beam. This project would be the first beam-driven wakefield acceleration experiment in Europe, and the first proton-driven plasma-wakefield acceleration experiment worldwide. We have set as an initial goal the demonstration of 1 GeV energy gain for electrons in 10 m of plasma. A proposal for reaching 100 GeV within 100 m of plasma will be developed using results from the initial round of experimentation. It is envisaged that the proposed experimental setup can be extended in the future to perform additional advanced accelerator research at CERN. The proposed location of the experiment in TT4/TT5 is compatible with such future usages. The proto-collaboration is already significant in size, and includes expertise from previous PWA experiments.