The 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<inline-formula><tex-math notation="LaTeX">\theta</tex-math></inline-formula> 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.
The luminosity upgrade of the Large Hadron Collider involves large modifications of the magnets close to the interaction regions. In particular, the double-aperture separation/recombination dipoles ...D2 shall deliver a field integral of 35 <inline-formula> <tex-math notation="LaTeX">\text{T}\cdot\text{m}</tex-math></inline-formula>. Given the physical and geometrical constraints limiting the length to less than 10 m, these magnets must be superconducting and shall generate a magnetic field higher than 3.5 T. Since the magnetic field direction is identical in both apertures (105 mm each one), the magnetic field between the two apertures sums up to high values, locally saturating the shielding iron yoke surrounding both coils. In order to decouple the magnetic field in the two apertures, a strategy has been developed based on three pillars: 1) no iron is placed in between the coils (thus limiting saturation effects); 2) each coil is asymmetric in a way to cancel the magnetic crosstalk to each other; 3) the yoke is suitably profiled for minimizing the variation in the harmonic components due to iron saturation. Based on these concepts, a 2-D magnetic optimization was carried out, leading to an acceptable field quality with a limited variation of the multipoles as the magnet field is raised from the injection value to the maximum value (4.5 T). A 2-D mechanical design was also performed with the aim at simplifying the construction issues and keeping under control the parameters relevant to beam optics (beam separation and magnetic multipoles). Finally, the coil ends were designed, too, and a complete model 1.5 m long drafted. This paper discusses in detail all these aspects, with some considerations about the future developments preliminary to the mass production.
A 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.
The next upgrade for the Large Hadron Collider (LHC), called High-Luminosity LHC, has the aim of increasing the rate of collisions of the accelerator by a factor of ten. To achieve this goal, the ...dipole and quadrupole magnets before and after the interaction region of the ATLAS and CMS experiments will be replaced. One of these is the separation-recombination dipole MBRD, which features a target integral magnetic field of 35 T<inline-formula><tex-math notation="LaTeX">\cdot</tex-math></inline-formula> m in a double aperture of 105 mm, obtained with a magnetic field of 4.5 T along a magnetic length of 7.78 m. One of the main challenges in the development of this magnet is the fact that the two apertures must have the same polarity and this causes a magnetic cross-talk between them. Because of this, it has been necessary to develop a left/right asymmetric aperture coil design for the coils to compensate this effect, that would have generated unwanted multipoles. Another problem related to the same polarity in the two apertures is a repulsive Lorentz force between them, which has been managed through the implementation of Al alloy sleeves assembled around the two collared apertures. The design was carried out in the framework of a CERN-INFN Genova agreement and the construction is ongoing in the industry ASG Superconductors. The 1.6 m long model was built and successfully cold tested, followed by the construction of a full-length prototype, recently delivered to CERN, while the construction of the series of 6 magnets is foreseen to be started at the beginning of 2022. This contribution will describe the prototype assembly status, also covering the field quality (FQ) aspect, discussing the results of the warm magnetic measurements at ASG and their implication in the design of the series in terms of harmonic content.
The Main Bending Recombination Dipole (MBRD), or D2, is one of the magnets foreseen by the High-Luminosity upgrade of the Large Hadron Collider (LHC). D2 features a double aperture, Nb-Ti, cos ...<inline-formula><tex-math notation="LaTeX">\theta</tex-math></inline-formula> dipole, with a central field of 4.5 T for a length of 7.78 m, hence with an integrated magnetic field of 35 T<inline-formula><tex-math notation="LaTeX">\cdot</tex-math></inline-formula> m, in a 105 mm bore. The project includes the fabrication of a 1.6 m long model, a full-length prototype and six series magnets, two of which are spare. Till now, the short model and the prototype have been successfully constructed and tested in 2020 and 2023, while the series magnets are presently under manufacturing and the warm magnetic measurements of the first built magnet were performed at the end of July 2023. This contribution will report the final field quality analysis of the prototype and the preliminary one of the series magnets, including results of the first measurements at room temperature (RT), a comparison with the ROXIE simulations and the expected field quality at operating conditions.
As 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 <inline-formula><tex-math notation="LaTeX">\theta</tex-math></inline-formula> 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.
CERN is currently investigating the feasibility of a future collider - the Future Circular Collider (FCC) - as a potential successor of the Large Hadron Collider (LHC), providing scientists with a ...powerful discovery tool in the field of high energy physics. INFN developed the main 16 T Nb 3 Sn dipole of the FCC based on the cos-theta coil design. The baseline design of the superconducting magnet adopts the bladder-and-key concept and includes 4-layered asymmetric coils, an aluminum shell and a welded stainless-steel skin. The scope of this collaborative work between INFN, CERN, UPATRAS and FEAC, is to validate and further study the baseline design. This paper describes the design concept and the fully parametric multi-physics finite and boundary element (FEM and BEM) model. The baseline assembly parameters are presented while the study of geometrical, material and assembly parameters, unveils the optimized structure.
The Superconducting Ion Gantry (SIG) project aims to design, construct, and test a curved superconducting dipole demonstrator magnet for an ion gantry (up to a rigidity of 6.6 Tm). The main ...demonstrator magnet parameters are a dipolar field of 4 T generated into a toroidal aperture with an 80 mm diameter, 1.65 m curvature radius, and 30° angular sector. The project is inserted in the framework of the EuroSIG collaboration among CNAO, CERN, INFN, and MedAustron. Within this collaboration, the main goal of SIG is to perform a feasibility study of winding and assembling cos-<inline-formula><tex-math notation="LaTeX">\theta</tex-math></inline-formula> coils with a small curvature radius. In addition, a parallel program at CERN is dedicated to the study of the indirect cooling problem through the construction of a straight thermal demonstrator magnet sharing the SIG cross-section. The basic idea behind these programs is to check whether the vast experience of the community on superconducting accelerator magnets design can lead to a breakthrough in the gantry magnets domain. This article shows the main elements of the conceptual design of the SIG magnet and reports on the first winding trial performed at the LASA laboratory, in Milan, with a copper dummy cable. Moreover, possible solutions for the winding, curing, and impregnation of highly curved cos<inline-formula><tex-math notation="LaTeX">\theta</tex-math></inline-formula> coils are discussed.
Next generation ion therapy magnets both for gantry and for accelerator (synchrotron) are under investigation in a recently launched European collaboration that, in the frame of the European H2020 ...HITRI plus and I.FAST programmes, has obtained some funding for work packages on superconducting magnets. Design and technology of superconducting magnets will be developed for ion therapy synchrotron and -especially- gantry, taking as reference beams of 430 MeV/nucleon ions (C-ions) with 10 10 ions/pulse. The magnets are about 60-90 mm diameter, 4 to 5 T peak field with a field change of about 0.3 T/s and good field quality. The paper will illustrate the organization of the collaboration and the technical program. Various superconductor options (LTS, MgB 2 or HTS) and different magnet shapes, like classical CosTheta or innovative Canted CosTheta (CCT), with curved multifunction (dipole and quadrupole), are under evaluation, CCT being the baseline. These studies should provide design inputs for a new superconducting gantry design for existing facilities and, on a longer time scale, for a brand-new hadron therapy centre to be placed in the South East Europe (SEEIIST project).
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