Experimental study on low-velocity-spread axis-encircling electron beam

摘要

The axial velocity spread of the axis-encircling electron beam generated by 30 kV Pierce-type cusp gun is measured. A pin-hole and phosphor screen was adapted to measure the axial velocity spread and a capacitive probe was used to measure the velocity ratio. Using the measured value of the velocity ratio, the axial velocity spread can be calculated by measuring the angle of the beam arc that is sampled by a pin-hole. The experimental data were compared with the analytical and numerical estimations.