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CAPACITIVE HIGH POWER INPUT COUPLER FOR SUPERCONDUCTING CAVITIES POWER |
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M.V. Lalayanª¹, O.V. Novicov¹, N.P. Sobenin¹, A.A. Krasnov², A.A. Zavadtsev², D.A. Zavadtsev² ¹Moscow Engineering Physics Institute (State University), Moscow, Russia ²Nano Invest, Moscow, Russia Abstract The results of calculation of 500 kW input coupler for superconducting accelerating cavity. The input coupler is built on base of loop antenna. The input coupler allows us to adjust external Q-factor in range of 10 times. ª – corresponding author |
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CROSSOVER RESISTANCE OF SUPERCONDUCTING CABLE FOR FAST-RAMPING MAGNETS OF PARTICLE ACCELERATORS |
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I.V. Bogdanovª, S.S. Kozub, P.A. Shcherbakov, L.S. Shirshov, P.I. Slabodchikov, L.M. Tkachenko, V.V. Zubko Institute of High Energy Physics, Protvino, Russia Abstract Fast-cycling magnetic fields, produced by superconducting magnets of modern accelerators, generate cable losses, which reduce with increase of contact resistance between wires in the cable. On the other hand the contact resistance has to have enough small value in order to provide flow of currents between wires. At IHEP it was carried out the study of crossover resistances in Rutherford type superconducting cable with a different resistive coating of wires in order to find the optimal coating, satisfying both above-mentioned conditions. Values of crossover resistance were measured for 19-strand cables, made from wires with NbTi filaments into copper matrix with a different coating (Ni, Cr and natural oxide). Also dependence of resistance on pressure was studied in the region, corresponding for pressure values, produced in the coils of superconducting magnets for accelerators. Besides the obtained experimental results, the description of features of samples and measuring technique are presented as well as the outcome of calculations of cable component of losses for fast-ramping dipole magnet with two-layer coil. ª – corresponding author |
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STABILITY STUDY OF HIGH-CURRENT SUPERCONDUCTING CABLES FOR ACCELERATOR MAGNETS |
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L. Shirshovª, I. Bogdanov, S. Kozub, P. Shcherbakov, P. Slabodchikov, L. Tkachenko, V. Zubko Institute of High Energy Physics, Protvino, Russia Abstract One of the main requirements to superconducting magnet is its stability, what can be estimated by means Minimum Quench Energy. MQE of Rutherford-type cables with different resistive coating of composite Cu-matrix NbTi multifilament strands has been measured. The equipment for MQE measurements of short cable samples versus magnetic fields is described. Current through the hairpin sample is created by superconducting transformer; the critical current of the primary winding is 100 A, which allows one to measure MQE of short samples at currents up to 15 kA. Current through the sample is measured with help of Rogowsky coil and integrator. In order to generate the heat disturbance in samples, the miniature heaters are used. The energy, released in heater, is changed step by step consecutively and the threshold energy, which causes quench (i.e. MQE), is found by this way. We measured dependencies of MQE upon the sample currents as well critical currents for the superconducting cables in magnetic fields up to 6.5 T. Experimental study of MQE was performed for 19-strands transposed cables, consisting of 0.85 mm diameter wires with natural oxide, Ni and Cr resistive coatings. A computer code for calculations of MQE in a cable has been created. ª – corresponding author |
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