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Photoelectron shield for the first mirror of a soft X-ray beamline

Authors :
Hirokazu Tanaka
Shohei Yamashita
Daisuke Wakabayashi
Yasuo Takeichi
Akio Toyoshima
Source :
Journal of synchrotron radiation. 28(Pt 1)
Publication Year :
2020

Abstract

At a soft X-ray beamline with an undulator source, significant heat generation at the first-mirror chamber and light emission at the viewport were found, which can be explained by photoelectrons from the mirror. The chamber temperature increases up to approximately 50°C over a period of several hours. A photoelectron shield consisting of thin copper plates not only prevents the heat generation and light emission but also improves the pressure of the vacuum chamber, if a voltage of a few tens of V is applied to the shield. The total electron yield of the shield reached as much as 58 mA under high heat-load conditions, indicating the emission of numerous photoelectrons from the first mirror. Heat-balance analyses suggest that approximately 30% or more of the heat load on the first mirror is transferred to the surroundings.

Details

ISSN :
16005775
Volume :
28
Issue :
Pt 1
Database :
OpenAIRE
Journal :
Journal of synchrotron radiation
Accession number :
edsair.doi.dedup.....d091e6df60d646112bf19115c7e5cb93