title: Twin helical undulator beamline for soft X-ray spectroscopy at SPring-8.
abstract: A very high resolution soft X-ray beamline, BL25SU, has been designed and is under construction at SPring-8. Completely right or left circularly polarized light is supplied on a common axis of a newly designed twin helical undulator. A helicity modulation up to 10 Hz can be performed using five kicker magnets. The fundamental radiation covers the region 0.5-3 keV. Higher-order radiation is rather weak on the axis. A monochromator with varied-line-spacing plane gratings is installed to cover the region below 1.5 keV. A very high resolution beyond 10(4) is expected for the whole energy region.
authors.affiliation: JAERI-RIKEN SPring-8 Project Team, Kamigori, Ako-gun, Hyogo 678-12, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Saitoh
authors.forename: T
authors.initials: T
authors.lastname: Nakatani
authors.forename: T
authors.initials: T
authors.lastname: Matsushita
authors.forename: T
authors.initials: T
authors.lastname: Miyahara
authors.forename: M
authors.initials: M
authors.lastname: Fujisawa
authors.forename: K
authors.initials: K
authors.lastname: Soda
authors.forename: T
authors.initials: T
authors.lastname: Muro
authors.forename: S
authors.initials: S
authors.lastname: Ueda
authors.forename: H
authors.initials: H
authors.lastname: Harada
authors.forename: A
authors.initials: A
authors.lastname: Sekiyama
authors.forename: S
authors.initials: S
authors.lastname: Imada
authors.forename: H
authors.initials: H
authors.lastname: Daimon
authors.forename: S
authors.initials: S
authors.lastname: Suga