Effect of Eddy Currents Induced in the Thermal Shield During the Quench of the Superconducting Coils for the Super-FRS of the FAIR Project

International audienceThe Superconducting FRagment Separator (Super-FRS) is a two-stage separator to be built next to the site of GSI, Darmstadt, Germany, as part of Facility for Anti-Proton and Ion Research. Its purpose is to create and separate rare isotope beams and to enable the mass measurement also for very short lived nuclei. Overall, the Super-FRS consists of 24 dipole magnets of so-called superferric type, with superconducting coils but the field shaped by magnetic iron. The coil is trapezoidal-shaped configuration, which is wound with NbTi wires of high Cu/Sc ratio and located inside a cryostat equipped with a thermal shield and cooled with liquid helium; but the dipole will have a warm iron yoke with a wide air trim slot. This paper presents the results of the eddy current calculations in the thermal shield induced during the quench of the magnet. The mechanical behavior of the thermal shield under the Lorentz forces generated by the eddy currents will also be presented

Evaluation of the effects of mechanical cycles on bonding of Al-superconducting cable in high-performance stabilized NbTi conductor

International audienceThe compact muon solenoid (CMS) solenoid is presently the superconducting magnet with the highest stored energy (about 2.6 GJ) and one with the highest energy/mass ratio (11.3 kJ/kg). The latter is directly related with the mechanical deformation of the conductor under the action of the magnetic force, inducing a strain as high as 0.15%, close to the elastic limit of materials. In order to provide the hoop strength in CMS magnet, an innovative reinforced Al-stabilized conductor was involved in the design. After 10 years of successful operation and in view of further runs (20 years or more), it seems appropriate to evaluate the robustness of the conductor with respect to thermal disturbances of mechanical origin. In order to understand the effects of magnet cycles on the bonding between the Rutherford cable and the pure aluminum stabilizer, we perform an experimental study on short samples of the full conductor. After stressing the conductor with mechanical cycles, electrical measurements at T = 4.2 K in magnetic field up to 5 T allowed us to evaluate the current transfer length, the relevant figure of merit for the bonding quality

Status of the High Power Couplers for ESS Elliptical Cavities

International audienceIn the framework of the European Spallation Source (ESS), CEA Paris-Saclay is responsible for the delivery of 30 cryomodules (9 medium beta (β = 0.67) and 21 high beta (β = 0.86) ones). Each cryomodule contains 4 elliptical cavities equipped with a radio frequency power coupler. The ESS nominal pulse is 1.1 MW maximum peak power over a width of 3.6 ms at a repetition rate of 14 Hz. The design of the couplers for medium beta and for high beta cavities is the same, except a small difference of the antenna penetration to adjust the Q_{ext}. The mass production of the 120 couplers started and all the medium beta couplers have been conditioned at room temperature. The first cryomodules equipped with the power couplers were successfully tested at high RF power and with cavities at 2K reaching the ESS nominal pulse. The main issue at the start of the series production could be fixed and it was due to bad TiN coatings that caused abnormal dielectric losses in the window. Thus, this paper deals with the TiN coating defect, presents the conditioning procedure and gives a conditioning report of these 36 couplers

JT-60SA TF magnet assembly

JT-60SA will be the world’s largest superconducting tokamak when it is assembled in 2020 in Naka, Japan(R = 3 m, a = 1.2 m). It is being constructed jointly by institutions in the EU and Japan under the BroaderApproach agreement. The assembly of its 400-tonne toroidalfield (TF) magnet, designed for an on-axisfield of2.25 T, was completed in July 2018. Consideration of its assembly throughout the design process, with asso-ciated consultation and testing, allowed high positional accuracy and hence respect for magneticfield tolerancesto be achieve

Results of the RF Power Tests of the ESS Cryomodules Tested at CEA

International audienceEight of the medium and high beta cryomodules deliv-ered to ESS by CEA are tested at CEA before delivery; the two medium and high beta prototypes and the three first of each type of the series. The goal of these tests is to validate the assembly and the performances on few cryomodules before the next cryomodules of the series are delivered to ESS. This paper summarizes the general results obtained during the tests at 2 K and at high RF power, Pmax = 1.1 MW. The cavities reach the ESS re-quirements, E_{acc} = 16.7 MV/m (Medium beta) and 19.9 MV/m (High beta) with an efficient compensation of the Lorentz detuning by the piezo tuner over the full RF pulse length of 3.6 ms at 14 Hz. After the successful tests at CEA, the first cryomodules have been shipped to ESS where the final acceptance test are performed

Examination and Characterization of Physical and Mechanical Properties of the ITER Central Solenoid Module Coils

The ITER Central Solenoid (CS) consists of a stack of six independent coil packs called modules. It features a total height of 18 m and a diameter of over 4 m. The modules are in an advanced stage of fabrication and testing by the US ITER Project Office (USIPO) and its subcontractor General Atomics (GA). A qualification module mockup at one to one scale but of reduced height was wound and Vacuum Pressure Impregnated (VPI) by GA to validate final manufacturing, using tooling and processes fully representative of a series module. The module was submitted to a thermal cycle down to the temperature of 4.5 K at which the coils will be cooled by supercritical helium. During plasma operation, the CS modules are subjected to a complex combination of static and dynamic forces. The understanding of the mechanical behaviour of the CS module coils is of paramount importance to analyse and predict the overall response of the CS stack. To this purpose, an extensive programme of investigation of the module mockup has been defined and applied. This allowed assessing, through examination and testing of a large number of VPI conductor array samples extracted from the mockup, the soundness of the coil through advanced non-destructive examination techniques including X-ray microtomography, dimensional metrology measurements and micro-optical observations. Moreover, additional testing of physical and mechanical properties carried out at room and cryogenic temperature allowed the behaviour of the conductor stacks to be assessed. The paper summarises the results of these investigations and their interpretation through mechanical analyses based on the individual properties of the coil constituents

JT-60SA Magnet System Status

The JT-60SA experimental device will be the world’s largest superconducting tokamak when it is assembled in 2019 in Naka, Japan (R=3m, a=1.2m). It is being constructed jointly by institutions in the EU and Japan under the Broader Approach agreement.Manufacturing of the six NbTi equilibrium field coils, which have a diameter of up to 12 m, has been completed. So far 13 of the 18 NbTi toroidal field coils, each 7 m high and 4.5 m wide, have also been manufactured and tested at 4 K in a dedicated test facility in France. The first three of four Nb3Sn central solenoid modules have been completed, as have all of the copper in-vesselerror field correction coils.Installation of the toroidal field magnet, around the previously welded 340° tokamak vacuum vessel and its thermal shield, started at the end of 2016 and is currently underway. The TF magnet will in turn support the EF and CS coils.25th International Conference on Magnet Technology (MT-25

JT-60SA Magnet System Status

The JT-60SA experimental device will be the world’s largest superconducting tokamak when it is assembled in 2019 in Naka, Japan (R = 3 m, a = 1.2 m). It is being constructed jointly by institutions in the EU and Japan under the Broader Approach agreement. Manufacturing of the six NbTi equilibrium field (EF) coils, which have a diameter of up to 12 m, has been completed. So far, 13 of the 18 NbTi toroidal field (TF) coils, each 7-m high and 4.5-m wide, have also been manufactured and tested at 4 K in a dedicated test facility in France. The first three of four Nb3Sn central solenoid (CS) modules have been completed, as have all of the copper in-vessel error field correction coils. Installation of the TF magnet, around the previously welded 340° tokamak vacuum vessel and its thermal shield, started at the end of 2016 and is currently underway. The TF magnet will in turn support the EF and CS coils

A new Time-of-flight detector for the R 3 B setup

© 2022, The Author(s).We present the design, prototype developments and test results of the new time-of-flight detector (ToFD) which is part of the R3B experimental setup at GSI and FAIR, Darmstadt, Germany. The ToFD detector is able to detect heavy-ion residues of all charges at relativistic energies with a relative energy precision σΔE/ ΔE of up to 1% and a time precision of up to 14 ps (sigma). Together with an elaborate particle-tracking system, the full identification of relativistic ions from hydrogen up to uranium in mass and nuclear charge is possible.11Nsciescopu