In this paper we present experimental and theoretical studies of the implantation profile of positrons emitted from ^{22}Na radionuclide into layered sample. The measured profile for the nonsymmetrical, around the positron emitter, stack of aluminium and silver foils was measured using the depth scanning of implantation profile technique. For the description of the obtained results two theoretical approaches were applied. The first one was the Monte Carlo simulation using the GEANT4 tool kit. The generated profile does not reproduce accurately the experimental profile. We proposed the multiple scattering model based on the fact that a positron due to backscattering can travel as an energetic particle several times through the whole sample before it annihilates. In this model absorption is also taken into account. The multiple scattering model algorithm was implemented in the LYS-1 program. The calculated profile using the LYS-1 program reproduces the experimental profile with much better accuracy.
Based on the study of explosive emission, the dielectric enhanced electric-field emission model is brought forward, and the metal-dielectric complex cathode material is manufactured. Based on the investigation of surface-flashover explosive emission, the graphite-carbon fiber complex cathode is manufactured, too. Then the experiments are developed respectively, and the results show the electron emission density of these two complex cathode materials is also more than 17 kA/cm^{2}, and their lifetime is exceeding 10^{5} pulses.
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