title: Measurement of back-bombardment temperature rise in microwave thermionic electron guns.
abstract: We describe a simple method to measure the back-bombardment heating temperature rise as a function of time in pulsed microwave thermionic guns using a fast rise-time InGaAs detector and optical pyrometer. Gaining knowledge of the nature of that temperature rise and the corresponding current out of the gun are the first steps in devising a scheme to counteract the back-bombardment heating which lengthens the micropulses, limits the macropulse length, and increases the energy spread of the emitted electron beam. We measured a temperature rise of 59 K in our LaB6 cathode which delivered a peak of 600 mA over a 5 μs RF pulse in our 0.33 MV/cm peak field, 2.856 GHz thermionic electron gun.
authors.affiliation: Department of Physics and Astronomy, University of Hawai'i at Mānoa, 2505 Correa Rd., Honolulu, Hawai'i 96822, USA.
authors.forename: Jeremy M D
authors.initials: JM
authors.lastname: Kowalczyk
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hadmack
authors.forename: John M J
authors.initials: JM
authors.lastname: Madey