Search

In this paper, we will report on the manufacturing of 6 helium inlet mock-ups for the EU ITER TF coils, and on the results of the mock-up tests and other qualification activities carried out in the European industry on this subject.

The ITER magnetic system includes 18 Toroidal Field (TF) Coils constructed using Nb3Sn cable-in-conduit superconductor. Each TF coil comprises a Winding Pack (WP) composed of 7 Double Pancake (DP) modules stacked together, impregnated and inserted into a stainless steel coil case. Fusion for Energy [the European Domestic Agency (DA)] is responsible for the procurement of the ten while the Japanese DA is responsible for remaining nine coils. The conductors are being produced by 6 different DAs, while the coil cases only by the Japanese DA. F4E has implemented a procurement strategy aimed to minimize costs and risks, consisting of subdividing the procurement into three main procurement packages, each foreseeing first an R&D and qualification phase. One procurement package is related to the construction of 72 radial plates (RP), another to the fabrication of the ten WP, and a third to the cold test and coil-case insertion of ten WP. In collaboration with industry, F4E has successfully produced two RP prototypes. Regarding the DP, the construction of the first DP prototype has started. In this paper, we will report on the results achieved so far and the status of each of the procurement packages.

The BABAR Detector, located in the PEP-II B-Factory at the Stanford Linear Accelerator Center, includes a large 1.5 Tesla superconducting solenoid, 2.8 m bore and length 3.7 m. The two layer solenoid is wound with an aluminum stabilized conductor which is graded axially to produce a +/- 3% field uniformity in the tracking region. This paper summarizes the 3 year design, fabrication and testing program of the superconducting solenoid. The work was carried out by an international collaboration between INFN, LLNL and SLAC. The coil was constructed by Ansaldo Energia. Critical current measurements of the superconducting strand, cable and conductor, cool-down, operation with the thermo-siphon cooling, fast and slow discharges, and magnetic forces are discussed in detail.

The 1.5 T superconducting solenoid is part of the BaBar detector located in the PEP-II B-Factory machine at the Stanford Linear Accelerator Center. The solenoid has a 2.8 m bore and is 3.7 m long. The two layer solenoid is wound with an aluminum stabilized conductor which is graded axially to produce a +/3% field uniformity in the tracking region. The 24 month fabrication, 3 month installation and 1 month commissioning of the solenoid were completed on time and budget. This paper summarizes the culmination of a 3 year design, fabrication and testing program of the BaBar superconducting solenoid. Critical current measurements of the superconducting strand, cable and conductor, cool-down, operation with the thermosyphon cooling, fast and slow discharges, and magnetic forces are discussed in detail.

A cable in conduit superconducting magnet for an MHD experimental linear generator is under construction at Ansaldo workshop in Genova. A unique technique that doesn't require the winding form has been adopted for the coils fabrication; it will allow the construction of large size MHD magnets. In the following, after a brief description of the constructive details of the components of this 5 T, 62 MJ magnet, we report a description of the fabrication technique, of the experience gained during the manufacturing and the characteristics of the obtained product. >

Ansaldo Componenti is carrying out the design of a superconducting dipole magnet to be employed in an experimental MHD (magnetohydrodynamic) generator. The magnet is a rectangular saddle-shaped dipole with an on-axis field of 5 T, an active length of 2 m, a 0.7*0.5 m warm bore, and a stored energy of 62 MJ. It will be the first MHD magnet wound by a cable-in-conduit superconductor; this choice was made in order to employ a conductor concept and a technology scalable to larger-size MHD magnets. The main aspects of the superconductive and mechanical design are reported. >

The thin solenoid for the Zeus detector has been installed and tested in HERA (Hadron Electron Ring Accelerator) at DESY. The coil reached the design magnetic field (1.8 T in the center) without training. During the test some measurements were made in order to investigate the cooling system and the quench-back behavior. No spontaneous quenches occurred. Several induced fast discharges showed the evidence of a quench-back effect, and the quench-back starting time was less than 1 s. The cylinder temperature measurements during the coil discharge perfectly agree with adiabatic calculations. The indirect cooling efficiency was verified for the two-layer winding. The tests performed showed that the magnet can operate safely at the nominal field.

A bath-cooled superconducting solenoid with a 280-nm-diameter warm bore, a coil length of 1200 mm, and a central field of 5 T at the rated current of 950 A has been built. It will operate as the compensating coil inside the Zeus detector at HERA (the Hadron Electron Ring Accelerator) at Desy. The coil is shielded by a 3.5-ton low carbon steel cold yoke, and the cold helium chamber was designed to withstand a maximum pressure of 20 bar. The main results obtained during the cool down and energization are reported.

The next generation neutrino mass experiment KATRIN (Karlsruhe Tritium Neutrino experiment) uses a series of superconducting magnet systems, which guide the electrons from tritium beta-decay adiabatically from the source to the detector within a magnetic flux of 0.0191 . The electron transport and tritiuAm pumping sections contain two complex magnet systems; the Differential Pumping Section (DPS2-F) and the Cryogenic Pumping Section (CPS) that are designed with a central magnetic flux density from 5 T to 5.7 T for persistent-mode operation. Each system has a series of superconducting solenoids in a zigzag arrangement that is designed to enhance the tritium pumping efficiency. The 7 m long DPS2-F was commissioned at the end of 2010 and the magnetic performance of the DPS2-F was accepted for the KATRIN experiment. The DPS2-F was operated for more than 325 hours in persistent-mode to investigate long term field stability, which is required to stay within 0.01% at the nominal field for a 60-day measurement run. All seven modules of the CPS were manufactured and successfully cold-tested.

The construction progress status of the superconducting magnets for the ZEUS detector, commissioned by INFN Frascati and to be installed in the HERA e- p+ring (DESY, Hamburg), is reported. The first one is a double layer, two densities, aluminum stabilized coil 1849 mm in inner dia., 2487 mm in length and 32.6 mm thick, with a central field of 1.8 T and high particle transparency. The second one is a compensating magnet, wound by a copper stabilized Nb-Ti cable. Its coil has a central field of 5 T, inner dia. 370 mm, a length of 1200 mm and is inserted into a cold iron yoke. The main problems encountered during the large coil construction and the geometrical accuracy obtained are reported. Four splices among the high purity aluminum stabilized cable length were made. An outer support cylinder, 18 mm thick, was shrink fitted around the coil and then the temporary inner mandrel was removed. The distribution of mechanical stresses was measured in the different configurations. A large aluminum alloy vacuum chamber with high radiation transparency was built. The compensating coil is ready to be installed inside its stainless steel cryostat. The cryostat critical features are the high design pressure (20 bar) and the heavy cold mass.

A thin solenoid and a compensating solenoid which will be installed in the ZEUS detector at the Hadron Electron Ring Accelerator collider are described. The thin solenoid of 1.88-m diameter, 2.5 m in length, is characterized by a high magnetic-field level (B=1.8 T), two-layer winding and variable linear current density. The improvements on the general design, the cable design, and measurements on the prototype cable are reported and discussed in detail. The solenoid, wound in two layers of Al-stabilized NbTi/Cu superconductor, will operate at 5000 A. Indirect cooling through the external restraining cylinder will ensure an operating temperature lower than 4.5 K. The required field homogeneity will be achieved by grading the current linear density along the solenoid axis instead of using end correction coils. >