The low count rate of (e, 2e) electron momentum spectroscopy (EMS) has long been a major
limitation of its application to the investigation of molecular dynamics. Here we report a new
EMS apparatus developed for time-resolved experiments in the nanosecond time scale, in
which a double toroidal energy analyzer is utilized to improve the sensitivity of the
spectrometer and a nanosecond pulsed electron gun with a repetition rate of 10 kHz is used
to obtain an average beam current up to nA. Meanwhile, a picosecond ultraviolet laser with …