  Beam diagnostics is important to guarantee good quality of beam in particle
accelerator. Both the electron and positron run in the tunnel in some modern
electron positron colliders such as Circular Electron Positron Collider (CEPC)
to be built and Beijing Electron Positron Collider II (BEPC II). To measure the
electron and positron beams, picking up of these two different bunches in real
time is of notable concern. Because the time interval between adjacent electron
and positron bunches is quite small, for example, 6 ns in CEPC, high-speed
switch electronics is required. This paper presents the prototype design of a
high-speed radio frequency (RF) electronics that can pick up nanosecond
positron-electron beam bunches with a switching time of less than 6 ns. Fast
separation of electron and positron is achieved based on RF switches and
precise delay adjustment of the controlling signals (~10 ps). Initial tests
have been conducted in the laboratory to evaluate the performance of
electronics, the results indicate that this circuit can successfully pick up
the bunch signal within a time interval of 6 ns, which makes it possible to
further measure the electron and position beams simultaneously.
