title: Duty factor variation possibility from 1% to 100% with PKU microwave driven Cs-free volume H⁻ sources.
abstract: Microwave driven cesium-free volume H(-) sources, that have the ability to deliver tens of mA H(-) at 35 keV both in CW and 10% duty factor (100 Hz/1 ms), were developed at Peking University (PKU) [S. X. Peng et al., in Proceeding of IPAC 2015, WEPWA027, Richmond, Virginia, USA, 3-8 May 2015]. Recently, special efforts were paid on the investigation of duty factor variation possibility from 1% to 100% with them. Most of the experiments were carried out with a pulsed length (τ) of 1 ms and different intervals of 99 ms, 49 ms, 39 ms, 29 ms, 19 ms, 9 ms, 4 ms, 2 ms, 1 ms, 0.5 ms, and 0 ms, respectively. Other experiments were focused on CW operation and fixed duty factor of 1%. Experimental results prove that PKU H(-) sources can deliver tens of mA H(-) at duty factor from 1% to 100%. The RF power efficiency increases steadily with the increasing of duty factor from 1% to CW at a fixed pulsed length. Under a given duty factor and pulsed length, RF power efficiency keeps constant and the H(-) current increases with RF power linearly. Details will be presented in the paper.
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: S X
authors.initials: SX
authors.lastname: Peng
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: T
authors.initials: T
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: H T
authors.initials: HT
authors.lastname: Ren
authors.affiliation: University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: A L
authors.initials: AL
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: J F
authors.initials: JF
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, School of Physics, Peking University, Beijing 100871, China.
authors.forename: J E
authors.initials: JE
authors.lastname: Chen