LOW ENERGY ELECTRON GUNS WITH HAIRPIN FILAMENTS M. Furuichi, L. Boesten, S. Nishida, and K. Okada Department of Physics, Sophia University, Chiyoda-ku, Kioicho 7-1, Tokyo, 102-8554 Japan We compare the performance (output current, angular distribution etc.) of typical 3-electrode Pierce-type guns, Repeller-type guns and triode guns for use at low energies (< 60-80 V) by numerical simulation. The program is based on the charge simulation method and includes space-charge effects.