The ATLAS detector at the CERN LHC is equipped with a superconducting magnet system consisting of three large toroids and a solenoid. The 2.3 m diameter, 5.3 m long solenoid is located at the heart of the experiment where it provides a 2 T field for spectrometry of the particles emanating from the interaction of the counter-rotating beams of hadrons. As the electromagnetic calorimeter of the experiment is situated outside the solenoid, the coil must be as transparent as possible to traversing particles. The magnet, which was designed at KEK, incorporates progress in technology coming from the development of previous solenoids of this type, in particular that of a new type of reinforced superconductor addressing the requirement of transparency. Special attention has been paid to ensuring reliability and ease of operation of the magnet, through the application of sufficiently conservative guidelines for the mechanical and electrical design, stringent testing during manufacture, and a comprehensive commissioning program. This report gives an overview of the design, manufacture, test, installation and commissioning of the ATLAS central solenoid.

The ATLAS central solenoid

The ATLAS central solenoid magnet is being constructed to provide a magnetic field of 2 T in the central tracking part of the ATLAS detector. As a key technology for a solenoid coil as thin as possible, a high-strength aluminum stabilized superconductor has been developed, achieving a yield strength of >100 MPa at 4.2 K. This paper describes the status of the design and development of the solenoid magnet.

/pdf/design-and-development-of-the-atlas-central-solenoid-magnet-5a2vqrw7pv.pdf

Design and development of the ATLAS central solenoid magnet

An update report on the National High Magnetic Field Laboratory (NHMFL) magnet analysis code is presented. Among the recent improvements to the code is the ability to address complex conductors, windings and reinforcements in terms of thermal and magnetic diffusion. In this article we present several examples showing the capabilities of this code. For example copper/stainless steel, Cu/SS wires that are used in pulse magnets as an alternative to other conductors such as CuAg or CuNb have shown to have excellent thermal and mechanical properties. It was found that the rule of mixtures holds in predicting their properties. As a result it is expected that wires that have 10%Cu and 90%SS will essentially keep the SS high modulus and strength. However the 10% copper will improve the conductivity of this reinforcement that it can act as quench-back circuit in case of a quench. In this study we simulated a quench of a high field (20 T) magnet system and varied the Cu/SS ratio. The modeling results show that 5%Cu is enough to make the reinforcement act as quench-back circuit.

Quench, thermal, and magnetic analysis computer code for superconducting solenoids

Since the discovery of superconductivity almost a century ago, there has been a steady increase in the variety of superconducting magnet applications. Progress in superconducting magnet technology has resulted in applications in areas of basic science, medicine, separation, and levitation. Performance improvements in a variety of materials, from low-temperature to high-temperature superconductors, are the foundation of recent rapid development. In addition, large increases in affordable computing power, along with steady refinement of three-dimensional analytical tools and improved materials characterization, have allowed many more advanced magnet concepts to be realized directly in hardware without scale prototype testing than was previously possible. This in turn has broadened opportunities for new science and technology results in many fields including the basic sciences, medical imaging, fusion, environmental remediation, and transportation. In this paper, a few examples of these applications will be discussed, representing a range in magnetic field, current density, and overall size, from the practical to the developmental.

Superconducting magnets and their applications

A prototype thin superconducting solenoid magnet has been developed to verify technical feasibility of an advanced thin superconducting solenoid magnet with a magnetic field of 2 T in a cylindrical volume of 3.4 m /spl phi//spl times/9 m and with a transparency of 1.2 radiation length (Xo). The magnet is required to have a stored energy/effective cold mass (E/M) ratio of 7.5 kJ/kg. The technical goal has been successfully achieved with realizing E/M=9.6 kJ/kg as a result of the prototype R&D. The prototype development and test results are presented. >

/pdf/development-of-a-prototype-thin-superconducting-solenoid-3qid95dpo1.pdf

Development of a prototype thin superconducting solenoid magnet for the SDC detector

A thin superconducting solenoid magnet has been designed for the SDC detector, which is one of major colliding particle detectors for the SSC high energy particle accelerator project. Based on recent R&D efforts to develop a high strength aluminum stabilized superconductor and a honeycomb/isogrid vacuum shell, the thin solenoid has been designed to provide a central magnetic field of 2 T in a tracking volume of 3.4 m phi *8.8 m, with a magnet wall transparency 1.2 Xo. The authors describe the conceptual design and the R&D work. To minimize material in the solenoid, technical guidelines incorporated into the solenoid design are outlined, and material savings are discussed. The cryostat and cryogenic design are considered. A R&D program is in progress to develop a prototype solenoid magnet with a full diameter and a quarter length to verify the SDC solenoid design. >

Design study of a thin superconducting solenoid magnet for the SDC detector

The Mu2e experiment at Fermilab is devoted to search for the conversion of a negative muon into an electron in the field of a nucleus without emission of neutrinos. One of the main parts of the Mu2e experimental setup is its Target Station in which negative pions are generated in interactions of the 8-GeV primary proton beam with a tungsten target. A large-aperture 5-T superconducting production solenoid (PS) enhances pion collection, and an S-shaped transport solenoid (TS) delivers muons and pions to the Mu2e detector. The heat and radiation shield (HRS) protects the PS and the first TS coils. A beam dump absorbs the spent beam. In order for the PS superconducting magnet to operate reliably the sophisticated HRS was designed and optimized for performance and cost. The beam dump was designed to absorb the spent beam and maintaining its temperature and air activation in the hall at the allowable level. Comprehensive MARS15 simulations have been carried out to optimize all the parts while maximizing muon yield. Results of simulations of critical radiation quantities and their implications on the overall Target Station design and integration will be reported.

https://s3.cern.ch/inspire-prod-files-a/a8df0493e13dc421f3ed3d2707f210a9

Ang Lee

Papers

Development of a prototype thin superconducting solenoid magnet for the SDC detector

Design study of a thin superconducting solenoid magnet for the SDC detector

Target Station Design for the Mu2e Experiment