The continuity of the 18, 13, and 2 kA circuits of the HL-LHC magnets heavily relies on splices and electrical connections, to which it is worth devoting a special attention from the early phases. ...This spans the design of the splice or connection itself, together with the tooling and related procedure, so that the execution can reliably yield high quality results. Mindful of the history of LHC splices, robustness and reproducibility of the execution solutions are two of the fundamental parameters that have guided the technical choices made during the development phase. The number of technical solutions considered is due to the variety of possible combinations, depending on the various nature and geometry of the superconducting cables to be joined together. This wide spectrum calls for a rigorous qualification protocol, including micrography, mechanical tests before and after fatigue stress and electrical tests at room and cryogenic temperature. The article will illustrate the choices made during the development phase for the 11 selected families of splices and electrical connections, together with their qualification process, while providing results and statistics from the mechanical and electrical tests campaigns.
A number of physics experiments call for the use of iron-dominated, normal-conducting electromagnets to produce moderate fields (2 T range) in a large gap or over a large volume. Although robust and ...reliable, these magnets require significant electrical power, in the MW range, and can thus be costly to operate, especially in DC mode. We report on the design and test of a superconducting, proof-of-principle demonstrator that makes use of technological developments carried out for the High Luminosity upgrade of the Large Hadron Collider at CERN (HL-LHC). The demonstrator includes a superconducting coil, wound from a MgB 2 cable, and mounted inside an iron yoke with a 62 mm gap. As a first phase, the demonstrator was successfully tested in liquid helium at 4.5 K, generating a magnetic flux density of 1.95 T at a current of 5 kA. In a second phase, currently under preparation, the demonstrator will be tested in gaseous helium at 20 K. The design concepts of the demonstrator can be scaled up to large, iron-dominated electromagnets.
Background
Literature lacks data on correlations between epidemiology and clinical data of patients with distal radius fractures (DRFs).
Aim
The aim of this study was to present a detailed ...epidemiologic survey of a large consecutive series of patient with DRFs.
Materials and Methods
This retrospective study included 827 consecutive patients (579 females, 248 men) who sustained a DRFs in the last 5 years. All fractures were radiographically evaluated. DRFs were classified according to Association of Osteosynthesis classification. Data on age, gender, side, period in which fracture occurred, and fracture mechanism were collected. Statistical analysis was performed.
Results
The patients’ mean age was 60.23 standard deviation (SD) 16.65 years, with the left side being most frequently involved (56.1%). The mean age of females at the time of fracture was significantly higher than that of males.
The most frequent pattern of fracture was the complete articular fracture (64.3%), while the most represented fracture type was 2R3A2.2 (21.5%). Regarding the period in which the fracture occurred, 305 DRFs (37.5%) were observed in the warmer months and 272 (33.4%) in the colder months. Low-energy trauma occurring outside home was found to be the major cause of DRF throughout the year.
In both genders, trauma mechanism 2 was more frequent (59.4% F; 31.9% M;
p
< 0.01).
A bimodal distribution of fracture mechanisms was found in males when considering the patient’s age with a high-energy mechanism of fracture (3 and 4), identified in 21% (
n
= 52) of males aged 18–45 years, and a low-energy mechanism (1 and 2) was observed in 39.9% (
n
= 99) of males aged > 45 years. A significant correlation between all trauma mechanisms (from 1 to 6) and different fracture patterns (complete, partial, and extraarticular) was found (
p
value < 0.001). The mean age of patients with extraarticular fractures (mean age 61.75 years; SD 18.18 years) was higher than that of those with complete (mean age 59.84 years; SD 15.67 years) and partial fractures (mean age 55.26 years; SD 18.31 years). Furthermore, considering different fracture patterns and patient age groups, a statistically significant difference was found (
p
< 0.001).
Conclusions
DRFs have a higher prevalence in females, an increase in incidence with older age, and no seasonal predisposition. Low-energy trauma occurring at home is the main cause of fracture among younger males sustaining fractures after sports trauma; Complete articular is the most frequent fracture pattern, while 2R3A2.2 is most frequent fracture type.
Level of evidence
Level IV; case series; descriptive epidemiology study.
We report preliminary designs for the arc dipoles and quadrupoles of the FCC-ee double-ring collider. After recalling cross sections and parameters of warm magnets used in previous large ...accelerators, we focus on twin aperture layouts, with a magnetic coupling between the gaps, which minimizes construction cost and reduces the electrical power required for operation. We also indicate how the designs presented may be further optimized so as to optimally address any further constraints related to beam physics, vacuum system, and electric power consumption.
In this article, we attempt to summarize the 5-year long involvement of PSI through the CHART MagDev program with R&D on the Canted Cosine Theta (CCT) technology as a candidate for an FCC-hh main ...dipole magnet. We present the test results of the Canted Dipole 1 (CD1) 1-m-long 10-T Nb<inline-formula><tex-math notation="LaTeX">_{3}</tex-math></inline-formula>Sn demonstrator magnet, as well as a subjective list of 'pros and cons' of CCT for the FCC-hh that we compiled along the way. By sharing our conclusions, we hope to contribute to an ongoing discussion, while maintaining our utmost respect to the community of CCT developers. The presented findings and conclusions are not final, and we remain open to arguments and discussions, as well as technical exchanges on the topic.
Subscale Stress-Managed Common Coil Design Araujo, D. M.; Auchmann, B.; Brem, A. ...
IEEE transactions on applied superconductivity,
08/2024, Letnik:
34, Številka:
5
Journal Article
Recenzirano
In the context of the High-Field Magnet (HFM) Programme, hosted at CERN, and the Swiss Accelerator Research and Technology (CHART) Initiative, hosted at PSI, the Magnet Development (MagDev) project ...aims to contribute to the Future Circular Collider (FCC) studies through, among others: (i) research on enabling technologies and (ii) high-field Low Temperature superconducting (LTS) and High Temperature Superconducting (HTS) magnets. After a first experience with the CD1 magnet, a Canted-Cosine-Theta (CCT) Nb 3 Sn demonstrator, a roadmap has been established with milestones ranging from enabling technologies tested in powered samples and coils, to ultimate-field and hybrid LTS/HTS short magnets. This article describes the conceptual design of the subscale stress-managed common-coils platform, which is an R&D vehicle for testing enabling technologies, innovative design concepts, and LTS and hybrid LTS/HTS coils. The different aspects of the design will be discussed, including the concept proposed for this platform, magnetic design, coil-ends optimization, and mechanical analysis.
In the context of high-energy physics, the use of Nb 3 Sn superconducting magnets as a cost-effective and reliable technology depends on improvements in the following areas: long development and ...manufacturing cycles, conductor degradation after thermal cycling, long training, as well as a demonstration in accelerator magnets with a beam aperture of the full potential of modern Nb 3 Sn conductors. In short, performance, robustness, and cost are the three issues to be addressed. The Magnet Development project (MagDev) of the Swiss Accelerator Research and Technology initiative (CHART) at the Paul Scherrer Institute (PSI) aims to contribute to the solutions to each of these issues, re-thinking the manufacturing and design process. In our program, every innovation is to be validated by means of a panoply of fast-turnaround tools: from non-powered and powered samples and coils, tested under background field, to low-field subscale magnets and high field short prototypes. This work presents one element in this panoply of R&D vehicles: a stress-managed Nb 3 Sn coil called BigBOX, impregnated with paraffin wax, and tested, through a collaboration with the Magnet Development Program of the United States (US-MDP), in the background field of Brookhaven National Laboratory (BNL)'s common coils dipole DCC17.
Abstract
The use of pressurized bladders for stress control of superconducting magnets was firstly proposed at Lawrence Berkeley National Laboratory in the early 2000s. Since then, the so-called ...‘bladders and keys’ procedure has become one of the reference techniques for the assembly of high-field accelerator magnets and demonstrators. Exploiting the advantages of this method is today of critical importance for Nb
3
Sn-based accelerator magnets, whose production requires the preservation of tight stress targets in the superconducting coils to limit the effects of the strain sensitivity and brittleness of the conductor. The present manuscript reports on the results of an experimental campaign focused on the optimization of the ‘bladders and keys’ assembly process in the MQXFB quadrupoles. These 7.2 m long magnets shall be among the first Nb
3
Sn cryomagnets to be installed in a particle accelerator as a part of the High Luminosity upgrade of the LHC. One of the main practical implications of the bladders technique, especially important when applied to long magnets like MQXFB, is that to insert the loading keys, the opening of a certain clearance in the support structure is required. The procedure used so far for MQXF magnets involved an overstress in the coils during bladder inflation. The work presented here shows that such an overshoot can be eliminated thanks to additional bladders properly positioned in the structure. This optimized method was validated in a short model magnet and in a full-length mechanical model, becoming the new baseline for the series production at CERN Furthermore, the results are supported by numerical predictions using finite element models.
The High-Luminosity project (HL-LHC) of the CERN Large Hadron Collider (LHC), requires low <inline-formula><tex-math notation="LaTeX">\beta</tex-math></inline-formula>* quadrupole magnets in Nb ...<inline-formula><tex-math notation="LaTeX">_\text{3}</tex-math></inline-formula>Sn technology that will be installed on each side of the ATLAS and CMS experiments. After a successful short-model magnet manufacture and test campaign, the project has advanced with the production, assembly, and test of full-size 7.15-m-long magnets. In the last two years, two CERN-built prototypes (MQXFBP1 and MQXFBP2) have been tested and magnetically measured at the CERN SM18 test facility. These are the longest accelerator magnets based on Nb <inline-formula><tex-math notation="LaTeX">_\text{3}</tex-math></inline-formula>Sn technology built and tested to date. In this paper, we present the test and analysis results of these two magnets, with emphasis on quenches and training, voltage-current measurements and the quench localization with voltage taps and a new quench antenna.
Abstract
Middle East Technical University Defocusing Beam Line (METU-DBL) performs the Single Event Effects (SEEs) radiation tests with protons in the range of 15 MeV to 30 MeV kinetic energy at ...Turkish Atomic Energy Authority Proton Accelerator Facility (TENMAK NÜKEN-PAF) for space and nuclear applications. The most critical beam transfer elements in the METU-DBL are three quadrupole magnets, which are used for defocusing the beam like optical lenses. The first two quadrupole magnets were purchased commercially, and the third quadrupole magnet was designed by the METU-DBL project team and manufactured by Sönmez Transformer Inc. in Turkey. Electronic, mechanic and magnetic capability tests of this custom-designed magnet were conducted both at TUBITAK and CERN facilities. After passing the acceptance tests, the magnet was certified by CERN and then installed to METU-DBL as a third quadrupole magnet. In this paper, we present details of the design, production and performed tests of the quadrupole magnet.
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