•A parametric APDL model of a 3D periodic multilayer CCT magnet has been developed.•Two 2D models of a multilayer CCT magnet have been developed.•Equations of the edges describing a CCT layer have ...been derived.•Homogenization method was used to obtain average orthotropic properties of the coil.•Variable anisotropic properties of the coils were derived for the 2D model.
CCT magnets are becoming more popular, especially as they provide support for each separate turn of a coils, thus significantly lowering the coil stresses and deformations. A four layer nested CCT dipole was designed at CERN as an R&D effort to study the possibility of using the CCT technology for such a complex magnet. Two pairs of layers produce dipole magnetic fields at 90° angles, allowing a 360° control over the resulting dipole field vector. In order to validate the design in terms of the mechanical strength and the allowed deformations, mechanical FEM models were needed. Three models, having different levels of geometrical details have been developed in the APDL language in the ANSYS software: a 3D model with periodic symmetry and two 2D models, one assuming very simplified geometry of the coils and the formers and the second one with real geometry of the coils and the formers. Realistic coils properties were accounted for via homogenization technique used to obtain average properties of the Nb-Ti strands and the cured resin. Orthotropic behavior of the coil was accounted for via rotations of the element coordinate systems in the 3D periodic model, and via anisotropic material properties for the detailed 2D model.
The electromagnetic (EM) analysis was done for the full 3D model of 1.4 m long nested CCT dipole. The EM forces were mapped to the 3D periodic models and the 2D models. The mechanical analysis consisted of the cool-down to 1.9 K in the first step and subsequent application of the nominal Lorentz forces. In addition, behavior at 1.9 K without thermal strains but only EM forces was studied to compute the maximum coil deformations – important to be kept low for good field quality.
All three FEM models have been successfully solved providing three estimations of the resulting deformations and stresses. The most loaded part was the interlayer insulation – due to the thermal strains and large torque between the layers, shear stresses above the safe level of 10 MPa were found. Another design was proposed to remove the possibility of the failure of the interlayer insulations via castellations in the formers. Further studies will include the full 3D model and a comparison to the periodic model, in order to find the most suitable boundary conditions for the periodic model. The detailed 2D model requires further developments in terms of electromagnetic force import. As the 2D model requires much less computational power w.r.t. the periodic 3D model, it shows a potential for more realistic geometrical modeling including the Nb-Ti strands and their Kapton insulation, to study the behavior of the interface between the strands, the cured resin, and the formers.
► The cyclic symmetry structure with special boundary conditions has been analyzed. ► Results based on the FE solid model and on the FE shell model have been compared. ► The effect of the missing ...mass contained has been checked.
The dynamic behaviour of the ITER Vacuum Vessel (VV) under seismic loads will be assessed by carrying out the modal analysis and then by applying the response spectrum method which describes earthquake motions. The effect of the missing mass is included in this last analysis. Numerical results are based on two different Finite Element (FE) models and on three different methods by which natural frequencies and mode shapes are defined. It means, it is applied the cyclic symmetry method, the component mode synthesis method and the 360° FE model of the VV. Comparisons between obtained results for the different models and methods are presented.
We present performance studies of a full-length prototype for the CASTOR quartz-tungsten sampling calorimeter, installed in the very forward region of the CMS experiment at the LHC. The response ...linearity and energy resolution, the uniformity, as well as the showers’ spatial properties in the prototype have been studied with electrons, pions and muons of various energies. A special study was also carried out for testing the light-output with a 90-degree cut of the quartz plates of the calorimeter. The data were taken during the CASTOR test beam at CERN/SPS in 2007.
The T2K Side Muon Range Detector (SMRD) Aoki, S.; Barr, G.; Batkiewicz, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2013, Letnik:
698
Journal Article
Recenzirano
Odprti dostop
The T2K experiment is a long baseline neutrino oscillation experiment aiming to observe the appearance of νe in a νμ beam. The νμ beam is produced at the Japan Proton Accelerator Research Complex ...(J-PARC), observed with the 295km distant Super-Kamiokande Detector and monitored by a suite of near detectors at 280m from the proton target. The near detectors include a magnetized off-axis detector (ND280) which measures the unoscillated neutrino flux and neutrino cross-sections. The present paper describes the outermost component of ND280 which is a Side Muon Range Detector (SMRD) composed of scintillation counters with embedded wavelength shifting fibers and Multi-Pixel Photon Counter readout. The components, performance and response of the SMRD are presented.
The single mirror Small Size Telescope (SST-1M) is one of the proposed designs for the smallest type of telescopes, SSTs that will compose the Cherenkov Telescope Array (CTA).
The SST-1M camera will ...use Silicon PhotoMultipliers (SiPM) which are nowadays commonly used in High Energy Physics experiments and many imaging applications. However the unique pixel shape and size have required a dedicated development by the University of Geneva and Hamamatsu. The resulting sensor has a surface of ∼94mm2 and a total capacitance of ∼3.4nF. These unique characteristics, combined with the stringent requirements of the CTA project on timing and charge resolution have led the University of Geneva to develop custom front-end electronics.
The preamplifier stage has been tailored in order to optimize the signal shape using measurement campaigns and electronic simulation of the sensor. A dedicated trans-impedance pre-amplifier topology is used resulting in a power consumption of 400mW per pixel and a pulse width <30ns. The measurements that have led to the choice of the different components and the resulting performance are detailed in this paper.
The slow control electronics was designed to provide the bias voltage with 6.7mV precision and to correct for temperature variation with a forward feedback compensation with 0.17°C resolution. It is fully configurable and can be monitored using CANbus interface. The architecture and the characterization of the various elements are presented.
Preliminary design of the COMPASS upgrade tokamak Vondracek, P.; Panek, R.; Hron, M. ...
Fusion engineering and design,
August 2021, 2021-08-00, 20210801, 2021-08-01, Letnik:
169, Številka:
C
Journal Article
Recenzirano
Odprti dostop
COMPASS Upgrade is a new medium size, high magnetic field tokamak (R = 0.9 m, Bt = 5 T, Ip = 2 MA) currently under design in the Czech Republic. It will provide unique capabilities for addressing ...some of the key challenges in plasma exhaust physics, advanced confinement modes and advanced plasma configurations as well as testing new plasma facing materials and liquid metal divertor concepts.
This paper contains an overview of the preliminary engineering design of the main systems of the COMPASS Upgrade tokamak (vacuum vessel, central solenoid and poloidal field coils, toroidal field coils, support structure, cryostat, cryogenic system, power supply system and machine monitoring and protection system). The description of foreseen auxiliary plasma heating systems and plasma diagnostics is also provided as well as a summary of expected plasma performance and available plasma configurations.
PDF
