Jin Zhou

Design, development and fabrication for BESIII superconducting muon detector solenoid

The BESIII thin superconducting solenoid will generate 1.0 T central field with a field uniformity of 5% within the drift chamber. The superconducting coil winding has an ID of 2962 mm, an OD of 3002 mm and a length of 3550 mm. The overall magnet cryostat has an I.D. of 2750 mm (warm bore), an O.D. of 3390 mm and a length of 3910 mm. Rectangular Aluminum Stabilized Nb-Ti/Cu Superconductor, 3.7 mm /spl times/ 20 mm, is employed to wind the one-layer coil inside a hoop-force support cylinder. The winding is indirectly cooled by forced-flow two-phase liquid helium. The thermal shield is also indirectly cooled by two-phase liquid nitrogen circulating in a tracing tube. The 4.5 K coil together with its support cylinder weighs 3583 kg. It is supported by twenty-four radial supports and twenty-four axial supports. The supports are designed for electromagnetic de-centering forces of 63.7 kN radial and 122.3 kN axial in addition to a 3 g axial and radial acceleration load. The 80 K thermal shields are supported by eight cold mass supports against 3 g load. The detailed magnet and cryostat design and the design of cold mass support and the coil fabrication process will be discussed.

Test of BESIII Detector Magnet

The Beijing Spectrometer III (BESIII) detector magnet running in Beijing electron positron collider reached its nominal current successfully in 2008. The 3.39 m diameter, 3.91 m long superconducting solenoid magnet (SSM) provides a 1 Tesla central magnetic field. It was inner wound with aluminum stabilized NbTi/Cu cable and conduction - cooled with forced flow of two phase helium circulating in a tracing tube. A thermal shield was conduction - cooled with liquid nitrogen in the cryostat. This paper reports the experience of the test of the BESIII detector magnet.

Tests of 3 T Superconducting Electromagnetic Iron Separator

A 3 T central field Superconducting Electromagnetic Iron Separator (SEIS) has been designed, fabricated and tested at Institute of High Energy Physics (IHEP) of China. The SEIS system is deliberately designed to separate small pieces of hazardous ferromagnetic materials, such as detonators, from coal to achieve high purity and good yield. The SEIS system mainly consists of a NbTi superconducting magnet, a LHe recondensation type cryostat with two GM cryocoolers (31 W/40 K, 1 W/4.2 K), a pair of binary current leads (CL). The 1 ton cold mass was located in the cryostat of the system with 630 mm room temperature bore. The system is powered with a 250 A/50 V power supply, and has charging time and discharging time of 15 minutes and 20 minutes, respectively. It took 10 days for SEIS magnet to cool down from 300 K to 4.2 K and 6 days to accumulate LHe at designed level 360 mm. The SEIS magnet suffered no quench to reach its designed current, and operated stably during many experiments afterwards. The experiment research of the SEIS system is detailedly presented in this paper.

The BESIII detector magnet

Publisher Summary BESIII (Beijing Spectrometer III) is a detector designed to run in the autumn 2007 at a 1 ╳ 10 33 cm -2 s -1 luminosity @1.89 GeV at BEPCII (Beijing Electron–Positron Collider II) at IHEP Beijing. It has a 1 T superconducting solenoid magnet with the inner winding diameter of 2962 mm, winding length of 3532 mm, and a 600 tonne flux return yoke. The indirectly cooled, pure aluminum stabilized single layer coil is internally wounded with a 4 kA superconductor. The magnet design is described. The NbTi/Cu superconductor has been delivered and the critical current test of a short sample of the superconductor has been performed. An inner winding machine is under construction.