title: Operational evaluation of ultrahigh-vacuum protection systems for intense-photon-flux wiggler beamlines.
abstract: The ultrahigh-vacuum (UHV) protection system at the 2.5 GeV synchrotron radiation source (positron storage ring) at the Photon Factory allows the intense-photon-flux wiggler beamlines to operate safely during synchrotron radiation experiments for a long time. There are six high-power wiggler/undulator beamlines that provide intense photon-flux beams to the experimental hall. In the case of a possible instantaneous vacuum failure at the experimental hall, the intense photon-flux radiation from the wiggler could cause a meltdown of the titanium-alloy fast-closing valve. The authors have developed a UHV protection system. Upon a vacuum failure, the protection system can dump the positron beam by turning off the RF power in the four RF klystrons (150 kW maximum), and then initiate a blade closure of the fast-closing valve. In this paper, the operational performance of the vacuum protection system for the intense-photon-flux wiggler beamlines is evaluated and discussed regarding the actual vacuum deterioration downstream of a beamline at the experimental hall.
authors.affiliation: Photon Factory, High Energy Accelerator Research Organization (KEK), 1-1 Oho, Tsukuba 305, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Kanaya
authors.forename: S
authors.initials: S
authors.lastname: Asaoka
authors.forename: S
authors.initials: S
authors.lastname: Sakanaka
authors.forename: H
authors.initials: H
authors.lastname: Maezawa