| 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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| WEPLS099 |
Fault Detection and Identification Methods Used for the LHC Cryomagnets and Related Cabling
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2607 |
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- D. Bozzini, F. Caspers, V. Chareyre, Y. Duse, T. Kroyer, R. Lopez, A. Poncet, S. Russenschuck
CERN, Geneva
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Several non-standard methods for electrical fault location have been successfully developed and tested. As part of the electrical quality assurance program, certain wires have to be subjected to a (high) DC voltage for the testing of the insulation. With the time difference of spark-induced electromagnetic signals measured with an oscilloscope, fault localization within a ± 10 cm range has been achieved. Another method used and adapted for the particular needs, was the synthetic pulse time-domain reflectometry (TDR) by means of a vector network analyzer. This instrument has also been applied as a low frequency sweep impedance analyzer in order to measure fractional capacities of cable assemblies where TDR was not applicable.
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