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Helder Pais Da Silva

Bio: Helder Pais Da Silva is an academic researcher from CERN. The author has contributed to research in topics: Magnet & Electromagnetic coil. The author has an hindex of 3, co-authored 9 publications receiving 33 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the design evolution leading from a 65-GJ twin solenoid with forward dipoles design to the present baseline design that features three superconducting solenoids is discussed.
Abstract: As a part of the future circular collider conceptual design study for hadron-hadron physics (FCC-hh), conceptual designs of detector magnets are being developed to facilitate the measurement of particle products resulting from the 100-TeV collisions. This paper discusses the design evolution leading from a 65-GJ twin solenoid with forward dipoles design to the present baseline design that features three superconducting solenoids. The central magnet produces 4 T over a free bore of 10 m and a length of 20 m. The forward solenoids provide additional bending power to facilitate tracking of high-pseudo-rapidity particles. The combined stored energy of this system is 13.8 GJ. This design is discussed in terms of powering and quench protection, conductor composition, mechanical properties of the cold masses and vacuum vessels, stray fields, and heat loads. In addition, alternative designs are discussed, including an ultrathin superconducting solenoid concept with comparatively low stored magnet energy. Like the ATLAS central solenoid, this solenoid provides a magnetic field to the tracker, and particles have to tunnel through the solenoid before reaching the calorimeters. An iron yoke returns the flux, thus providing bending power for muon tagging and giving complete magnetic shielding.

13 citations

Journal ArticleDOI
TL;DR: In this paper, the Baby-MIND detector has been developed for the iron plates of the WAGASCI experiment at J-PARC (Japan), where the magnetization scheme optimizes flux return for minimum stray field and operating current, while maximizing the useful tracking area with $B > 1.5$ T.
Abstract: The Baby-MIND (magnetized iron neutrino detector) collaboration is building a muon detector to be installed downstream of the WAGASCI experiment at J-PARC (Japan). Due to the challenging timeline and space constraints for the installation in the ND280 pit, an innovative magnetization scheme has been developed for the iron plates. The magnetization scheme optimizes flux return for minimum stray field and operating current, while maximizing the useful tracking area with $B > 1.5$ T. The 33 iron plates of the detector are individually magnetized by coils wound on their surface by “sewing” an aluminum conductor through slits cut in the plates. In this paper, we present the details of the magnetization scheme and coil winding procedure as well as the results of magnetization tests performed on a prototype module and the first eighteen detector plates.

8 citations

Journal ArticleDOI
TL;DR: The BabyIAXO detector as discussed by the authors is based on a common-coil layout, comprising two flat racetrack coils of 10 m length spaced by 0.8 m. Uniquely, a group of two 1-stage GM and three 2-stage PT cryocoolers are used to transfer efficiently the available cooling capacity among the cold mass, thermal shield and current leads.
Abstract: Searching for axion like particles is one of the top priorities in particle physics. Using helioscopes is a promising technology to detect solar axions. In order to ensure readiness of the technology required for the International Axion Observatory (IAXO), the state-of-the-art facility in the field, a smaller scale but fully functional 10 m long twin bore demonstrator called BabyIAXO is prepared for construction in the early 2020s. Similar to IAXO, the two magnet bores have to point to the sun and thus to rotate 360° horizontally and ±25° vertically. The 50 MJ detector magnet of BabyIAXO is based on a common-coil layout, comprising two flat racetrack coils of 10 m length spaced by 0.8 m. Using Al-stabilized Rutherford cable with 8 NbTi strands of 1.4 mm diameter, the system can operate at 9.8 kA nominal current with 2 K temperature margin, while producing 2.0 T in the center of detection bores and 3.2 T peak field. The magnet may operate in persistent mode by using a thermally activated switch made of NbTi/CuNi matrix wire. The current leads are “over-current” designed in order to reduce the associated heat load during charging and long idle periods at full current. Uniquely, a group of two 1-stage GM and three 2-stage pulse-tube (PT) cryocoolers is used for precooling and maintaining 4.5 K in the coils. Two cryocirculators are used to transfer efficiently the available cooling capacity among the cold mass, thermal shield and current leads. While using “dry” cooling conditions, this cryogenic setup ensures cooling down the 15 t cold mass in 18 days. The relevance of design, construction, and operational experience gained with BabyIAXO for a fully fletched IAXO system is discussed.

4 citations

Journal ArticleDOI
29 Jun 2020
TL;DR: In this article, the first material of interest, Cryogel® Z, is shaped as a flexible composite blanket, which combines silica aerogel with reinforcing fibers and a density of 160 kg/m3, allowing a 4 m bore, 6 m long detector solenoid with a total thickness of 250 mm.
Abstract: The Future Circular Collider (FCC) study includes the design of the detector magnets for the FCC-ee+ (electron-positron) collider, requiring a 2 T solenoid for particle spectrometry, and for the FCC-hh (proton-proton) collider, with a 4 T detector solenoid. For both solenoids and their cryostats, CERN is developing an innovative and challenging design in which the solenoids are positioned inside the calorimeters, directly surrounding the inner tracker. For this purpose, the cryostats must be optimized to have maximum radiation transparency. They are structured as a sandwich of thinnest possible metallic shells for achieving vacuum tightness, supported by layers of low density and highly radiation transparent insulation material, still providing sufficient mechanical resistance and low thermal conductivity. In this respect, thermal and mechanical analysis of innovative insulation materials are currently being carried out. The first material of interest, Cryogel® Z, is shaped as a flexible composite blanket, which combines silica aerogel with reinforcing fibers and a density of 160 kg/m3. It allows a 4 m bore, 6 m long FCC-ee+ detector solenoid cryostat with a total thickness of 250 mm. CERN has investigated the compression of Cryogel® Z under 1 bar equivalent mechanical load and its thermal conductivity between 10 K and room temperature, as well as the critical phenomena of thermal shrinkage and outgassing. We present the test results, as a first overview on the material.

4 citations

Journal ArticleDOI
01 Jun 2020
TL;DR: In this paper, the electrical circuit of the BabyIAXO magnet and its protection layout when operated in persistent mode is presented, and the quench process is calculated using a 3-D thermo-electrical model of the coil windings.
Abstract: BabyIAXO, a 20 m-long twin-bore helioscope aiming for search of axion like particles, is currently in the engineering design phase and its construction is to be completed within the next 4 years. In addition to X-ray detectors and focusing optics, the system is equipped with a 50 MJ magnet with a common coil layout, containing two 10 m-long NbTi flat racetrack coils cooled by a group of cryocoolers. It has to operate at 10 kA, preferably in persistent mode with disconnected power supply, allowing to simplify the sun-tracking rotation system of BabyIAXO. A direct current mode is possible as well. Hence, quench protection is a high priority. Here, we present the electrical circuit of the BabyIAXO magnet and its protection layout when operated in persistent mode. The quench process is calculated using a 3-D thermo-electrical model of the coil windings, also accounting for the presence of the coil casing and the quench-back effect. Impact of the operating current, conductor properties, voltage detection threshold and location of hot-spot on the peak temperature is discussed. Quench protection aspects of the HTS busbars and persistent mode switch are also addressed.

3 citations


Cited by
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Journal ArticleDOI
TL;DR: In this article, a vacuum pressure impregnated, insulated, partially transposed, extruded, and roll-formed (VIPER) cable was designed and experimentally qualified.
Abstract: High-temperature superconductors (HTS) promise to revolutionize high-power applications like wind generators, DC power cables, particle accelerators, and fusion energy devices. A practical HTS cable must not degrade under severe mechanical, electrical, and thermal conditions; have simple, low-resistance, and manufacturable electrical joints; high thermal stability; and rapid detection of thermal runaway quench events. We have designed and experimentally qualified a vacuum pressure impregnated, insulated, partially transposed, extruded, and roll-formed (VIPER) cable that simultaneously satisfies all of these requirements for the first time. VIPER cable critical currents are stable over thousands of mechanical cycles at extreme electromechanical force levels, multiple cryogenic thermal cycles, and dozens of quench-like transient events. Electrical joints between VIPER cables are simple, robust, and demountable. Two independent, integrated fiber-optic quench detectors outperform standard quench detection approaches. VIPER cable represents a key milestone in next-step energy generation and transmission technologies and in the maturity of HTS as a technology.

83 citations

03 Dec 2018
TL;DR: The White Paper R&D project at CERN as discussed by the authors has defined a strategic research and development (R&D) program on technologies for future experiments, which will start in 2020 and initially extend over five years, provided the required resources can be made available.
Abstract: Instrumentation is a key ingredient for progress in experimental high energy physics. The Experimental Physics Department of CERN has defined a strategic R&D (Research and Development) programme on technologies for future experiments. Provided the required resources can be made available, it will start in 2020 and initially extend over five years. The selection of topics and the established work plans are the result of a transparent and open process, which lasted 14 months and involved several hundred of physicists and engineers at CERN and in the broader HEP community. This R&D programme is in the tradition of previous similar initiatives, the DRDC projects in the 1990’s and the White Paper R&D programme (2008-2011) that have been instrumental in providing the technologies which are presently in use at the LHC experiments or which will be deployed in the coming LHC upgrades (Phase-I and PhaseII). Examples of the achievements of the White Paper R&D programme are the validation of the CMOS 130 nm technology, the GEM single mask technique, radiation hard optical links, DC-DC converters and the CernVM file system. The results of this new R&D programme will be building blocks, demonstrators and prototypes, which will form the technological basis for possible new experiments and experiment upgrades beyond the LHC Phase-II upgrades scheduled for the long shutdown LS3. These include in particular detectors at CLIC, FCC-hh and FCC-ee but also further upgrades of the LHC experiments. The main challenges come on the hadron collider side from the very high luminosity operation, leading to extreme pile-up, track density, radiation loads and data throughput, but also from the need for unprecedented precision in vertexing and tracking, combined with very low material budgets and highly granular calorimetry on the lepton collider side. The new programme targets the primary challenges of the detectors complemented by equally demanding challenges in the domains of electronics, mechanics, cooling, magnets and software. A large part of the required R&D work will be carried out jointly with external groups from universities and research labs exploiting organically grown networks and relations, but also dynamic and efficient structures like the RD50 and RD51 collaborations. For many developments, close cooperation with industrial partners will be crucial.

30 citations

Journal ArticleDOI
TL;DR: Experimental results show that the proposed MOTS algorithm can effectively solve the problem even on a large scale and outperform the classic algorithm of nondominated sorting genetic algorithm-II (NSGA-Ⅱ).

20 citations

Journal ArticleDOI
TL;DR: In this article, the design evolution leading from a 65-GJ twin solenoid with forward dipoles design to the present baseline design that features three superconducting solenoids is discussed.
Abstract: As a part of the future circular collider conceptual design study for hadron-hadron physics (FCC-hh), conceptual designs of detector magnets are being developed to facilitate the measurement of particle products resulting from the 100-TeV collisions. This paper discusses the design evolution leading from a 65-GJ twin solenoid with forward dipoles design to the present baseline design that features three superconducting solenoids. The central magnet produces 4 T over a free bore of 10 m and a length of 20 m. The forward solenoids provide additional bending power to facilitate tracking of high-pseudo-rapidity particles. The combined stored energy of this system is 13.8 GJ. This design is discussed in terms of powering and quench protection, conductor composition, mechanical properties of the cold masses and vacuum vessels, stray fields, and heat loads. In addition, alternative designs are discussed, including an ultrathin superconducting solenoid concept with comparatively low stored magnet energy. Like the ATLAS central solenoid, this solenoid provides a magnetic field to the tracker, and particles have to tunnel through the solenoid before reaching the calorimeters. An iron yoke returns the flux, thus providing bending power for muon tagging and giving complete magnetic shielding.

13 citations

Journal ArticleDOI
TL;DR: In this paper , a simulation of a 5MW fully superconducting synchronous generator with combined excitation is presented, and the authors discuss the results of 3D finite element modeling (FEM) simulation.
Abstract: The use of liquid hydrogen as a fuel will be inevitable in the aviation of the future. This statement means that manufacturers will also implement liquid hydrogen for cooling all superconducting aviation equipment of an electric propulsion system. The development of fully electric aircraft is the most promising solution in this case. Scientists from the Department of electrical machines and power electronics of Moscow aviation institute have conducted calculations and theoretical researches of critical specific mass-dimensional parameters (MW/ton and MW/m3 at 21 K) of fully superconducting aviation synchronous generator of the electric propulsion system. The results are in this article. The article discusses the results 3D finite element modeling (FEM) simulation of a 5 MW fully superconducting synchronous generator with combined excitation. Superconducting armature and axial excitation windings based on second generation high temperature superconductors (HTS-2G) are located on the stator, which makes it possible to contactlessness and the absence of sliding seals. A dry gap will reduce gas-dynamic losses and increase the nominal peripheral speed of the rotor. The use of liquid hydrogen as a coolant makes it possible to significantly increase the linear load of the generator, and high current densities to reduce the cross-sectional area of the coils, which will make it possible to place them in individual cryostats in the future. Individual cryostats will allow to remove the heat release of magnetic losses from the cryogenic zone and reduce the consumption of refrigerant. For the purpose of internal redundancy of the HTS coils, the machine has a complete set of reserve winding made of ultrapure aluminum, also cooled by liquid hydrogen. If the superconducting coils get out of the stand, the generator will provide 15 % power on standby

11 citations