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MSC Seminars
Superconducting solenoid for MPD detector on heavy-ion collider NICA at JINR (Dubna)
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Europe/Zurich
30/7-010 (CERN)
Description
A.A. Efremov (Joint Institute for Nuclear Research, Russia), E.K. Koshurnikov (Neva-Magnet, S&E, Sankt-Peterburg, Russia), Yu.Yu. Lobanov (Joint Institute for Nuclear Research, Russia), A. S. Vodopyanov (Joint Institute for Nuclear Research, Russia)
Joint Institute for Nuclear Research (Dubna, Russia) is planning to build the heavy-ion collider NICA to study Au-Au collisions at energies up to 11 GeV/Nucleon. It is foreseen to install to detectors: Multi Purpose Detector (MPA) and Spin Physics Detector (SPD). The main constituent part of the Multi-Purpose Detector (MPD) on heavy-ion collider NICA at JINR (Dubna) is a large 0.5 T superconducting detector solenoid. It has to ensure the required resolution for transverse momenta over the range 0.1 3 GeV/c. The magnet inner dimensions are chosen as a compromise between the time of flight requirements to length of tracks to be sufficient for good particle identification and track reconstruction precision on one hand, and the needs in homogeneous magnetic field and reasonable cost of the magnet on the other hand. The magnet has to be commissioned at the beginning of 2014.
The magnet is designed as a superconducting solenoid with a flux return iron yoke and with aluminium stabilized coil implying an inner winding method and circulating indirect cooling. Two correcting coils with higher linear current density at each end of the SC coil are to suppress the radial component of the magnetic field in the tracker area.
The absence of requirement on the radiation transparency allows using a conservative coil design and inexpensive stainless steel cryostat. Diameter of the magnet aperture is 4 m, the distance between pole tips is 5.24 m. The magnet weight is about 450 ton. The field inhomogeneity in the tracker area of the detector is about 0.1%. Homogeneity of the radial component of the magnetic induction in the volume of Charged Particle Tracker (TPC) has to be < 0.775 mm. Maximal stored energy in the magnet winding is 7.8 MJ.
The flux return yoke of the magnet consists of a dodecahedral barrel and two end caps. The yoke design is similar to the STAR magnet yoke design - two supporting rings secure structural magnet stiffness, control azimuth and radial locations of each flux return bar and provide minimal deflections in the magnet structure under action of gravity and magnetic forces, which is required for high magnetic field quality. The weight of the cryostat and inner detectors is being transmitted to the supporting rings. Two end caps installed within the supporting rings form the magnet poles. The trim coils are embedded in the recesses on the pole tips. Both end caps can be promptly withdrawn in axial direction to provide access to the detectors.
The solenoid is mounted on rail-guided roller supports to be transported from the assembly area to its operational position.
Organised by
Ezio Todesco
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