Proposal to measure bunch lengths using a pulse dilation photomultiplier tube

Electron bunches in storage rings are typically short (~100 ps) and separated by long periods of time (>2 ns). A pulse dilation photomultiplier tube offers a new way of measuring high bandwidth optical pulses using low bandwidth oscilloscopes. Experiments performed by others have demonstrated a temporal resolution of 12 ps, meeting requirements for electron bunches expected for the Advanced Photon Source Upgrade. Compared to electrooptical streak cameras, we think that this may be a preferred technique for measuring the longitudinal profile of bunches in electron storage rings.