1,643 research outputs found
An Algorithm for Toroidal Field Harmonics Computation in Arbitrary Magnetic Configurations
No full textToroidal magnetic configurations are widely exploited in industry and scientific research, involving a vast spectrum of applications, such as thermonuclear fusion, particle detectors, SMES systems and medical devices. To properly design and analyse these systems, it is crucial to determine the magnetic field generated by different configurations. The multipole expansion theory can be applied to the analysis of toroidal conurations, by solving the Laplace equation for the magnetic scalar potential in toroidal coordinates. Contrarily to the case of accelerator magnets with straight axis, in this case the correlation between the current distribution and the field harmonics cannot easily be identified. This paper proposes a methodology for the computation of field harmonics in toroidal coordinates, which is validated by comparison with the results obtained through the Biot-Savart law. This work was carried out in the frame of the GaToroid project ongoing at CERN
Stability modeling of the LHC Nb-Ti Rutherford cables subjected to beam losses
No full textThe Large Hadron Collider (LHC) at CERN is being prepared for its full energy exploitation during run III, i.e., an increase of the beam energy beyond the present 6.5 TeV, targeting the maximum discovery potential attainable. This requires an increase of the operating field of the superconducting dipole and quadrupole magnets, which in turn will result in more demanding working conditions due to a reduction of the operating margin while the energy deposited by particle loss will increase. Beam-induced magnet quenches, i.e., the transition to normal conducting state, will become an increasing concern, because they could affect the availability of the LHC. It is hence very important to understand and be able to predict the quench levels of the main LHC magnets for the required values of current and generated magnetic fields. This information will be used to set accurate operating limits of beam loss, with sufficient but not excessive margin, so to achieve maximal beam delivery to the experiments. In this study we used a one-dimensional, multistrand thermal-electric model to analyze the maximum beam losses that can be sustained by the LHC magnets, still remaining superconducting. The heat deposition distribution due to the beam losses is given as an input for the stability analysis. Critical elements of the model are the ability to capture heat and current distribution among strands, and heat transfer to the superfluid helium bath. The computational model has been benchmarked against energy densities reconstructed from beam-induced main dipole quenches during LHC operation at 6.5 TeV. The model was then used to evaluate the stability margin of both main dipole and main quadrupole magnets at different beam energies, up to the expected ultimate operating energy of the LHC, 7.5 TeV. The comparison between the quench levels underlines how the increase of beam energy implies a substantial reduction of magnets stability and will require much stricter setting on the allowable beam losses to avoid resistive transitions during operation
Concentrazione di nitrati nel deflusso ipodermico di sistemi colturali di collina a diverso livello di intensificazione
No full textFelcini Editor
Design of a 4 T Curved Demonstrator Magnet for a Superconducting Ion Gantry
No full textThe Superconducting Ion Gantry (SIG) project is the contribution from INFN (the Italian National Institute for Nuclear Physics) to the international SIGRUM project with the aim of exploring new technological solutions for the critical elements of a 430 MeV/u carbon ion gantry. The project includes the design and construction of a cos theta 4 T superconducting dipole demonstrator magnet whose main scope is to prove the feasibility of winding and assembling an accelerator magnet type with a relatively small radius of curvature (1.65 m). In addition to the complexity due to the curvature, the target field ramp rate is 0.4 T/s and the cooling system must not adopt liquid helium. This paper discusses the design activities carried out in the last year on the electromagnetic and thermal domains and reports on the present concepts and infrastructure for the first winding trials
Design of a 4 T Curved Demonstrator Magnet for a Superconducting Ion Gantry
No full textThe Superconducting Ion Gantry (SIG) project is the contribution from INFN (the Italian National Institute for Nuclear Physics) to the international SIGRUM project with the aim of exploring new technological solutions for the critical elements of a 430 MeV/u carbon ion gantry. The project includes the design and construction of a cos\theta 4 T superconducting dipole demonstrator magnet whose main scope is to prove the feasibility of winding and assembling an accelerator magnet type with a relatively small radius of curvature (1.65 m). In addition to the complexity due to the curvature, the target field ramp rate is 0.4 T/s and the cooling system must not adopt liquid helium. This paper discusses the design activities carried out in the last year on the electromagnetic and thermal domains and reports on the present concepts and infrastructure for the first winding trials
Preliminary Study of 4 T Superconducting Dipole for a Light Rotating Gantry for Ion-Therapy
No full textA collaboration between CERN, CNAO, INFN, and MedAustron has been formed aiming at designing a light rotating gantry suitable for hadron therapy based on 430 MeV/n carbon ion beams. After a first design for a 3 T dipole field, as the backbone of the gantry magnetic system, now the collaboration is looking at an alternative design, for at least 4 T field with a faster ramp rate. The magnet is designed according to the cosθ layout to be wound with Nb-Ti superconducting Rutherford cable. One of the main challenges is the very small curvature radius of 1.65 m with a relatively large aperture, of 70-90 mm. Another challenge is the use of indirect cooling despite the cycling operation of 0.4 T/s. The paper reports the preliminary investigation for a 4.5 T dipole. The design will be followed by the construction of a 1 m long demonstrator to be manufactured and tested at INFN (LASA laboratory) in about three years. The conductor is a Rutherford cable of 2.6 μm Nb-Ti filament size, embedded in a Cu-Mn alloy matrix. The resulting gantry is very compact: the collaboration is working on integration between gantry structure and magnets to allow reducing the rotating weight in the range 50-80 tons, which is a factor 4 to 5 less than the present state-of-the-art
Characterization of Hysteretic Behavior of a FeCo Magnet for the Design of a Novel Ion Gantry
No full textIn the framework of the euroSIG project and within an international collaboration between CNAO, CERN, INFN, and MedAustron, the design of a novel gantry for hadron therapy based on superconducting magnets and a downstream scanning system has been undertaken. The choice of placing the scanning system downstream of the last superconducting dipole plays a crucial role in the overall layout of the gantry, having a direct impact on its radius, weight, and cost. The proposed design for the scanning system considers two separate normal-conducting scanning magnets with a central field in the order of 1 T, three times higher than the current state-of-the-art scanning magnets for hadron therapy. Such a magnetic field value for a fast-pulsed magnet poses interesting questions regarding non-linearities due to the yoke saturation, hysteretic effects, and eddy currents. In this context, it is important to develop reliable models to study the behavior of the magnet at various levels of current and magnetic field. For this reason, we implemented two and three-dimensional simulations of a short dipole with FeCo yoke and we validated them against experimental measurements. In this paper, we focus on the modelization of the hysteretic behavior of this magnet, providing insight into the feasibility of proposed scanning magnets
Modeling of Beam Loss Induced Quenches in the LHC Main Dipole Magnets
No full textThe full energy exploitation of the Large Hadron Collider (LHC), a planned increase of the beam energy beyond the present 6.5 TeV, will result in more demanding working conditions for the superconducting dipoles and quadrupoles operating in the machine. It is hence crucial to analyze, understand, and predict the quench levels of these magnets for the required values of current and generated magnetic fields. A one-dimensional multi-strand electro-thermal model has been developed to analyze the effect of beam-losses heat deposition. Critical elements of the model are the ability to capture heat and current distribution among strands, and heat transfer to the superfluid helium bath. The computational model has been benchmarked against experimental values of LHC quench limits measured at 6.5 TeV for the Main Bending dipole magnets
2D EM Design and Innovative Winding Technique for a 4 T High Curvature Superconducting Dipole in Block Coil Configuration for Next Generation Ion Gantries
No full textAs part of major European collaborations focused on the study of newly developed superconducting magnets for ion therapy, Istituto Nazionale di Fisica Nucleare (INFN) is directly involved through the Superconducting Ion Gantry (SIG) project. In ion therapy, rotating gantry systems are critical to better preserve healthy tissues during treatments, but they are typically huge and heavy structures: a superconducting version of them would lead to lighter and more viable solutions. SIG aims to design, in collaboration with Centro Nazionale di Adroterapia Oncologica (CNAO) and Conseil Européen pour la recherché Nucléaire (CERN), the main superconducting magnets for a 430 MeV/u carbon ion gantry. The main purpose of the project is to study the bending dipoles of this system: they are expected to have a curvature of 1.65 m, aperture of 80 mm, magnetic field of 4 T, ramp rates up to 0.4 T/s and Nb-Ti coils. Among the goal of SIG is the construction of a 30-degree demonstrator to prove the feasibility of these magnets. The plan is to design cos magnets, but we are currently working on an alternative strategy with cross section in block coil configuration. These parameters are very challenging and this solution could make it easier to achieve the required goals. In this work the optimized cross section and a novel winding technique for high curvature block coil magnets are presented
Winding Test Results of an Innovative Technique for Block Coil Curved Dipoles in the Development of a Gantry for Hadron-Therapy
No full textThe Superconducting Ion Gantry (SIG) project is the INFN (Istituto Nazionale di Fisica Nucleare) participation in the EuroSIG collaboration between INFN, CNAO, CERN and MedAustron. The EuroSIG main focus is on the exploration of new concepts and the prototype development of superconducting magnets used in hadron-therapy treatments. More specifically, in the SIG project, we are studying the most critical aspects of a 430 MeV/u superconducting carbon-ion gantry and particular attention is given to the design of 45-degree cosθ dipoles and the construction and testing of a 30-degree demonstrator. Although the baseline of the project is centered on cosθ-type magnets, we are working on an alternative strategy to mitigate the risk of failure in the construction of the demonstrator. This is a block coil type solution to avoid, with a simpler geometry, the difficulties of winding a curved cosθ dipole with significantly small curvature radius. In this context, an innovative winding technique was developed and tests have been conducted to confirm its feasibility. This contribution presents the results obtained from the winding tests in order to show the effectiveness of the method adopted to wind this type of coils and highlight possible improvements. In addition, an electromagnetic design concept for curved block coil dipoles has been developed, with the intention of proposing an optimized solution for the geometry of the coils, along with the method they can be wound
- …
