Problems in SuperKEKB Vacuum System During the Phase-1 Commissioning and Their Mitigation Measures

Suetsugu, Yusuke; Hisamatsu, Hiromi; Ishibashi, Takuya; Kanazawa, Ken-ichi; Shibata, Kyo; Shirai, Mitsuru; Terui, Shinji

doi:10.18429/JACoW-IPAC2017-WEPIK008

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RIS citation export for WEPIK008: Problems in SuperKEKB Vacuum System During the Phase-1 Commissioning and Their Mitigation Measures

TY - CONF
AU - Suetsugu, Y.
AU - Hisamatsu, H.
AU - Ishibashi, T.
AU - Kanazawa, K.
AU - Shibata, K.
AU - Shirai, M.
AU - Terui, S.
ED - Schaa, Volker RW
ED - Arduini, Gianluigi
ED - Pranke, Juliana
ED - Seidel, Mike
ED - Lindroos, Mats
TI - Problems in SuperKEKB Vacuum System During the Phase-1 Commissioning and Their Mitigation Measures
J2 - Proc. of IPAC2017, Copenhagen, Denmark, 14â19 May, 2017
C1 - Copenhagen, Denmark
T2 - International Particle Accelerator Conference
T3 - 8
LA - english
AB - The first (Phase-1) commissioning of the SuperKEKB, an energy-asymmetric electron-positron collider in KEK, Japan, started in February and ended in June, 2016. The vacuum system of the main ring worked well through the commissioning period as a whole, but experienced several problems, such as the electron cloud effect (ECE) in the positron ring, the pressure bursts accompanying beam losses due to dust particles in the beam pipe, an air leak at a connection flange due to the direct hitting of synchrotron radiation (SR), and so on. Towards the next (Phase-2) commissioning, countermeasures to these problems are taken during the shutdown period. For example, permanent magnets generating axial magnetic fields are attached to beam pipes at drift spaces for the suppression of the ECE. Knockers, which can artificially drop dust particles attached to the top surface in beam pipes by continuous impacts, are prepared to the beam pipes at which the pressure bursts had been frequently observed. Bellows chambers with masks are installed to protect the leaked flange from SR. The problems and their mitigation measures will be summarized in the presentation.
PB - JACoW
CP - Geneva, Switzerland
SP - 2925
EP - 2928
KW - wiggler
KW - vacuum
KW - electron
KW - photon
KW - positron
DA - 2017/05
PY - 2017
SN - 978-3-95450-182-3
DO - 10.18429/JACoW-IPAC2017-WEPIK008
UR - http://jacow.org/ipac2017/papers/wepik008.pdf
ER -