The development of a beam position monitor based on Cherenkov diffraction radiation for operation at the AWAKE experiment.

the AWAKE Collaboration is proposing a Run 2 experiment. The aims of the AWAKE Run 2 are to demonstrate acceleration of electrons to higher energies, whilst preserving beam quality, i.e. emittance, and charge preservation. The process should be scalable to longer lengths and will require

significant development of plasma cell technology. The ultimate aim of Run 2 is to have demonstrated the AWAKE scheme sufficiently such that particle physics experiments based on this scheme could be possible in the second half of the 2020s.

Expertise in design and delivery of electron beamlines as well as radio-frequency(RF) engineering will be crucial to the effort to design a new electron beamline with energies of O(100) MeV. The injection of the witness electron bunch is recognised as one of the key Run 2 tasks given the challenges experienced in Run 1 and careful design and commissioning will be necessary.

In particular, having expertise involved in all of these aspects, including optimisation and data taking, will significantly enhance the possible physics output of the experiment. The RF timing is another limitation from Run 1 and improvements to this have already started and will be vital for Run 2. Control of the more precise, significantly smaller in all axes, electron bunches presents a challenge we are well-equipped to meet.

We will apply our well-known expertise in delivery of cutting-edge and well-understood diagnostic systems to develop a suite of instrumentation which will allow us to fully characterise the electron beam before and after acceleration. This is essential for the aim of developing the AWAKE scheme into a useable technology for future accelerators. No less important, an extensive diagnostics suite will allow us to tune

and improve the experiment whilst taking data. We therefore propose to deliver instruments to measure the emittance of the initial and accelerated electron bunches; the length and transverse extent of the initial and and accelerated electron bunches as well as the proton bunches; and the accelerated electron energy distribution.