Beam Diagnostics with Smith–Purcell Radiation

Abstract The use of multiple gratings allows simultaneous sampling of the emitted radiation at a number of wavelengths and thus offers the prospect of determining the bunch profile in a single shot. This chapter reviews the criteria for deciding on the optimal number of sampling points and the methods of suppressing the background (i.e. non-Smith–Purcell) radiation through the use of filters and/or through the exploitation of the polarization properties of Smith–Purcell. The possible role of the grating itself as a source of blackbody background radiation is also assessed. Included in the chapter is an examples of a reconstructed time profile of a bunch with sub-picosecond full width at half maximum. There is also a brief discussion of the use of SP radiation as a monitor of the microbunch spacing in a train of microbunches.