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| WEPB09 |
Mechanical Design of the Intensity Measurement Devices for the LHC
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253 |
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- D. B. Belohrad, S. Longo, OP. Odier, S. Thoulet
CERN, Geneva
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The intensity measurement for the LHC ring is provided by eight current transformers: 2 DC current transformers (DCCTs) and 2 fast transformers (FBCTs) per vacuum chamber. The measurement precision of 1uArms at averaging over 1s time interval for the DCCTs and ±109 charges in 25ns bunch measurements for the FBCTs is required. Such constraints call for low noise electronics and a compact magnetically shielded mechanical design. Due to ultra high vacuum requirements in the LHC the vacuum chambers are equipped with the non-evaporable getter (NEG) film. The NEG is activated by heating the vacuum chamber to 200°C and more. Such temperatures affect the structure of the magnetic materials, which form the base part of the intensity measurement devices, and degrade their performance. A cooling circuit is needed. Due to the mechanical constraints, the cooling circuit, as well as heating element must form an integral part of the design. The paper presents the solution of these problems and discusses the mechanical construction of the DCCTs and FBCTs currently being installed in the LHC.
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