SECONDARY ELECTRON CURRENT FROM A PULSED ELECTRON ACCELERATOR

摘要

A 2 MEV electrostatic accelerator with a .06 microsecond pulsed electron source was found to produce radiation afterpulses occurring as late as 150 microseconds after cessation of the source pulse. The rate of afterpulsing was roughly proportional to the pressure in the accel¬eration and drift tube for pressures up to 5 x 10-5 mm of mercury and rose more steeply at higher pressures. The decay curve of the delayed radiation was independent of the target material and the type of detector used to study it. The energy spectrum was continuous, with an average energy less than that of the bremsstrahlung pulse. The cause of the effect has been determined to be ionization in the drfit tube by the primary electron beam. The mech¬anism for formation of the afterpulses and the instrumentation for their study are discussed.