Electro-optic measurement of the wake fields of 16 MeV electron bunches

The authors demonstrate the measurement in the time domain and with picosecond resolution of the high frequency electromagnetic fields generated by a bunched beam of 16 MeV electrons. A birefringent crystal placed 2 cm from the beam is sampled in time by a pulsed laser synchronized with the electron bunch. The electric field waveform has been recorded with substantial structure as late as 2.5 ns after the passage of the bunch.