ASSESSMENT OF THERMIONIC EMISSION PROPERTIES AND BACK BOMBARDMENT EFFECTS FOR LaB6 AND CeB6

The emission properties of LaB6 and CeB6 materials as a thermionic cathode were determined experimentally in the range 1650 ~1900 K using an electrostatic DC gun. The determined emission properties were used in a developed numerical simulation model to investigate and compare the heating properties of LaB6 and CeB6 as cathode materials for thermionic RF gun against Back Bombardment (BB) electrons effect. The estimated work functions from the experimental results at 1600 K for LaB6 and CeB6 were 2.76 and 2.69 eV respectively. While, the simulation results for the BB effect showed that, for 6 s pulse duration with 8 MW RF power, LaB6 cathode experiences a large changes in the cathode temperature and 30% higher change in the current density compared with CeB6.