Experimental study on electron beam energy recovery system using a laser-heated electron gun and a multistage electron collector for highly efficient beam application

An experiment on electron beam energy recovery systems has been performed using a laser-heated electron gun and a multistage electron collector. Modeling of the laser heating indicates that the cathode temperature is proportional to the one-fourth power of laser power. The energy recovery efficiency of 99.8% of the designed collector is calculated using a computer code with a beam current of about 10 mA and -75 keV. In the first phase of the recovery experiment, potentials of the collector electrodes are provided through a voltage divider of several hundred megaohms. In order to overcome the drawback of voltage-divider resistance, two high-voltage power supplies are provided in the second phase of the experiment, and charge and energy recovery efficiencies are measured.