| Paper |
Title |
Page |
| MOPCH191 |
Copper Heat Exchanger for the External Auxiliary Bus-bars Routing Line in the LHC Insertion Regions
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508 |
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- C. Garion, A. Poncet, F. Seyvet, J.-P.G. Tock
CERN, Geneva
- M. Sitko, B. Skoczen
CUT, Krakow
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The corrector magnets and the main quadrupoles of the LHC dispersion suppressors are powered by a special superconducting line (called auxiliary bus-bars line N), external to the cold mass and housed in a 50 mm diameter stainless steel tube fixed to the cold mass. As the line is periodically connected to the cold mass, the same gaseous and liquid helium is used for cooling the magnets and the line. The final sub-cooling process (from 4.5 K down to 1.9 K) consists of the phase transformation from liquid to superfluid helium. It is slightly delayed with respect to the magnets. To accelerate the process, a special heat exchanger has been designed. Located in the middle of the dispersion suppressor portion of the line it consists in creating a local sink of heat extraction, providing two additional λ fronts that propagate in opposite directions towards the line extremities. Both the numerical model and the sub-cooling analysis are presented in the paper for different configurations of the line. Design, manufacturing and integration aspects of the heat exchanger are described. Finally, the results of the qualification tests and the expected performance of the line are given.
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| THPCH183 |
Installation and Quality Assurance of the Interconnections between Cryo-assemblies of the LHC Long Straight Sections
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3227 |
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- C. Garion, I. Slits, J.-P.G. Tock
CERN, Geneva
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The interconnections between the cryomagnets and cryogenic utilities in the LHC long straight sections constitute the last machine installation activity. They are ensuring continuity of the beam and insulation vacuum systems, cryogenic fluid and electrical circuits and thermal insulation. The assembly is carried out in a constraining tunnel environment with restricted space. Therefore, the assembly sequence has to be well defined, and specific tests have to be performed during the interconnection work to secure the reliability of the system and thus to ensure the global accelerator availability. The LHC has eight long straight insertion zones composed of special cryomagnets involving specific interconnection procedures and QA plans. The aim of this paper is to present the installation and quality assurance procedures implemented for the LHC LSS interconnections. Technologies such as manual and automatic welding and resistive soldering will be described as well as the different quality controls such as visual and radiographic inspection of welds, electrical and leak testing. An evaluation and statistical analysis of the results of the interconnection work will be presented.
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