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Title |
Page |
| WEPC007 |
Vacuum Performance of the Diamond Light Source In-vacuum Insertion Devices
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1995 |
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- M. P. Cox, S. Bryan, B. F. Macdonald, H. S. Shiers
Diamond, Oxfordshire
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Diamond Light Source is the UK's new 3 GeV 3rd generation synchrotron light source with a 562 m circumference electron storage ring. At the start of user operations in January 2007, 5 in-vacuum undulators were in operation and a further 3 units have been installed subsequently. This paper describes the vacuum performance of these devices. 3 different mechanical configurations with different undulator canting angle and different pumping arrangements of the interconnecting vessels are installed. One configuration has non-evaporable getter (NEG) coated interconnecting vessels. Vacuum simulations were carried out on these configurations as part of the vacuum design process to predict their performance. Following final magnetic characterization, each of the devices was vacuum assembled and baked ex-situ for an extended period and then installed under dry nitrogen purge conditions, eliminating the need for a time-consuming in-situ bakeout in most cases. After a period of pump down and beam conditioning, the operating pressures in all the in-vacuum undulators were below the target specification and produced acceptably low Gas Bremsstrahlung radiation levels in the beamlines.
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| WEPC103 |
Design of a Cold Vacuum Chamber for Diagnostics
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2240 |
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- S. Casalbuoni, T. Baumbach, A. W. Grau, M. Hagelstein, R. Rossmanith
FZK, Karlsruhe
- V. Baglin, B. Jenninger
CERN, Geneva
- R. Cimino
INFN/LNF, Frascati (Roma)
- M. P. Cox
Diamond, Oxfordshire
- E. M. Mashkina
University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
- E. J. Wallén
MAX-lab, Lund
- R. Weigel
Max-Planck Institute for Metal Research, Stuttgart
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Preliminary studies performed with the cold bore superconducting undulator installed in the ANKA storage ring suggest that the beam heat load is mainly due to the electron wall bombardment. Low energy electrons (few eV) are accelerated by the electric field of the beam to the wall of the vacuum chamber, induce non-thermal outgassing from the cryogenic surface and heat the undulator. In this contribution we report on the design of a cold vacuum chamber for diagnostics to be installed in the ANKA (ANgstrom source KArlsruhe) storage ring and possibly in third generation light sources. The diagnostics implemented are: - retarding field analyzers to measure the electron energy and flux,
- temperature sensors to measure the total heat load,
- pressure gauges,
- and a mass spectrometer to measure the gas content.
The aim of this device is to gain a deeper understanding on the heat load mechanisms to a cold vacuum chamber in a storage ring and find effective remedies. The outcome of the study is of relevance for the design and operation of cold bore superconducting insertion devices in synchrotron light sources.
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