Estimation of the Necessary Bandwidth of the ELENA Longitudinal Schottky Pick-ups for Operation with Unbunched Beams

Schottky measurements are an important element of beam diagnostics. In the recently approved ELENA ring, a dedicated Schottky pick-up for longitudinal measurements is foreseen. This pick-up will be implemented by adapting the AD design which consists of two low-noise beam current transformers — one to cover a high frequency range (0.25 – 30MHz) and the other to cover a low frequency range (0.02 – 3MHz). It is of particular interest as to whether these designs can be used with only a change to the geometry, or if modifications are necessary to cope with the different requirements in ELENA. One important question is whether the frequency range covered by the pick-ups is sufficient. Therefore it is of particular interest to determine the necessary bandwidth for operation in ELENA. The present note is dedicated to this task using the scenario of unbunched beam operation, since in this case the signals are very weak and thus challenge the performance of the pick-up.