[10p-E311-1~13] 7.2 Applications and technologies of electron beams

2:15 PM - 2:30 PM JST(5:15 AM - 5:30 AM UTC)

[10p-E311-4] Investigation Thermionic-field emission operated under space charge situation using Particle in cell method

〇Yoichiro Neo^1,2, Teppei Narita², Hiroki Ito², Taisei Ito², Jonghyun Moon^1,2 (1.RIE Shizuoka univ., 2.Shizuoka univ.)

Keywords:

Space charge limited current

With a tungsten field emission cathode with surface-diffused gallium, as the emission current increases, only the emission area is locally heated by Joule heating, causing the emission mechanism to shift from thermal to field emission. The emission current reaches the space charge limited current (SCLC) region, enabling long-term stable operation. Conventional field emission cannot reach the SCLC region due to the reversal of cooling and heating in the Nottingham effect. Furthermore, measurements of the energy distribution revealed that in the SCLC state, the distribution spreads in both the acceleration and deceleration directions. We analyzed the thermionic and electron emission mechanisms using rigorous numerical calculations and analyzed changes in the SCLC energy distribution using the Particle-in-cell (PIC) method.