Work function of sintered lanthanum hexaboride

Abstract

A work function of 2.36 eV and a Richardson constant of 120 A/cm2 K2 have been measured for a hot-pressed porous lanthanum hexaboride rod cathode. It is shown that the LaB6 work function is highly susceptible to poisoning by molybdenum deposited at high temperatures during experiments. A stable work function of about 2.7 eV is then measured. After removal of the molybdenum by atomic iodine flux, the work function of clean LaB6 is restored.