title: Application of a simple asynchronous mechanical light chopper to multielectron coincidence spectroscopy.
abstract: A simple asynchronous mechanical light chopper, based on modification of a turbo-molecular pump, has been developed to extend the interval between light pulses in single bunch operation at the Photon Factory storage ring. A pulse repetition rate of 80 kHz was achieved using a cylinder rotating at 48000 rpm, with 100 slits of 80 microm width. This allows absolute timing of particles up to 12.48 micros instead of the single-bunch period of 624 ns. We have applied the chopper together with a light pulse monitor to measure multielectron coincidence spectra using a magnetic bottle time-of-flight electron spectrometer. With such a system, the electron energies are determined without any ambiguity, the folding of coincidence spectra disappears and the effect of false coincidences is drastically reduced.
authors.affiliation: Photon Factory, IMSS, KEK, Oho 1-1, Tsukuba, Ibaraki 305-0801, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Ito
authors.forename: Francis
authors.initials: F
authors.lastname: Penent
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Hikosaka
authors.forename: Eiji
authors.initials: E
authors.lastname: Shigemasa
authors.forename: Isao H
authors.initials: IH
authors.lastname: Suzuki
authors.forename: John H D
authors.initials: JH
authors.lastname: Eland
authors.forename: Pascal
authors.initials: P
authors.lastname: Lablanquie