669 research outputs found
The Superconducting Toroid for the New International AXion Observatory (IAXO)
IAXO, the new International AXion Observatory, will feature the most
ambitious detector for solar axions to date. Axions are hypothetical particles
which were postulated to solve one of the puzzles arising in the standard model
of particle physics, namely the strong CP (Charge conjugation and Parity)
problem. This detector aims at achieving a sensitivity to the coupling between
axions and photons of one order of magnitude beyond the limits of the current
detector, the CERN Axion Solar Telescope (CAST). The IAXO detector relies on a
high-magnetic field distributed over a very large volume to convert solar
axions to detectable X-ray photons. Inspired by the ATLAS barrel and end-cap
toroids, a large superconducting toroid is being designed. The toroid comprises
eight, one meter wide and twenty one meters long racetrack coils. The assembled
toroid is sized 5.2 m in diameter and 25 m in length and its mass is about 250
tons. The useful field in the bores is 2.5 T while the peak magnetic field in
the windings is 5.4 T. At the operational current of 12 kA the stored energy is
500 MJ. The racetrack type of coils are wound with a reinforced Aluminum
stabilized NbTi/Cu cable and are conduction cooled. The coils optimization is
shortly described as well as new concepts for cryostat, cold mass, supporting
structure and the sun tracking system. Materials selection and sizing,
conductor, thermal loads, the cryogenics system and the electrical system are
described. Lastly, quench simulations are reported to demonstrate the system's
safe quench protection scheme.Comment: To appear in IEEE Trans. Appl. Supercond. MT 23 issue. arXiv admin
note: substantial text overlap with arXiv:1308.2526, arXiv:1212.463
New Superconducting Toroidal Magnet System for IAXO, the International AXion Observatory
Axions are hypothetical particles that were postulated to solve one of the
puzzles arising in the standard model of particle physics, namely the strong CP
(Charge conjugation and Parity) problem. The new International AXion
Observatory (IAXO) will incorporate the most promising solar axions detector to
date, which is designed to enhance the sensitivity to the axion-photon coupling
by one order of magnitude beyond the limits of the current state-of-the-art
detector, the CERN Axion Solar Telescope (CAST). The IAXO detector relies on a
high-magnetic field distributed over a very large volume to convert solar
axions into X-ray photons. Inspired by the successful realization of the ATLAS
barrel and end-cap toroids, a very large superconducting toroid is currently
designed at CERN to provide the required magnetic field. This toroid will
comprise eight, one meter wide and twenty one meter long, racetrack coils. The
system is sized 5.2 m in diameter and 25 m in length. Its peak magnetic field
is 5.4 T with a stored energy of 500 MJ. The magnetic field optimization
process to arrive at maximum detector yield is described. In addition,
materials selection and their structure and sizing has been determined by force
and stress calculations. Thermal loads are estimated to size the necessary
cryogenic power and the concept of a forced flow supercritical helium based
cryogenic system is given. A quench simulation confirmed the quench protection
scheme.Comment: Accepted for publication in Adv. Cryo. Eng. (CEC/ICMC 2013 special
issue
Risk and Machine Protection for Stored Magnetic and Beam Energies
Risk is a fundamental consideration when designing electronic systems. For
most systems a view of risk can assist in setting design objectives, whereas
both a qualitative and quantitative understanding of risk is mandatory when
considering protection systems. This paper gives an overview of the risks due
to stored magnetic and beam energies in high-energy physics, and shows how a
risk-based approach can be used to design new systems mitigating these risks,
using a lifecycle inspired by IEC 61508. Designing new systems in high-energy
physics can be challenging as new and novel techniques are difficult to
quantify and predict. This paper shows how the same lifecycle approach can be
used in reverse to analyse existing systems, following their operation and
first experiences.Comment: 19 pages, contribution to the 2014 CAS - CERN Accelerator School:
Power Converters, Baden, Switzerland, 7-14 May 201
Insertion Magnets
Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC) : Preliminary
Design Report. The Large Hadron Collider (LHC) is one of the largest scientific
instruments ever built. Since opening up a new energy frontier for exploration
in 2010, it has gathered a global user community of about 7,000 scientists
working in fundamental particle physics and the physics of hadronic matter at
extreme temperature and density. To sustain and extend its discovery potential,
the LHC will need a major upgrade in the 2020s. This will increase its
luminosity (rate of collisions) by a factor of five beyond the original design
value and the integrated luminosity (total collisions created) by a factor ten.
The LHC is already a highly complex and exquisitely optimised machine so this
upgrade must be carefully conceived and will require about ten years to
implement. The new configuration, known as High Luminosity LHC (HL-LHC), will
rely on a number of key innovations that push accelerator technology beyond its
present limits. Among these are cutting-edge 11-12 tesla superconducting
magnets, compact superconducting cavities for beam rotation with ultra-precise
phase control, new technology and physical processes for beam collimation and
300 metre-long high-power superconducting links with negligible energy
dissipation. The present document describes the technologies and components
that will be used to realise the project and is intended to serve as the basis
for the detailed engineering design of HL-LHC.Comment: 19 pages, Chapter 3 in High-Luminosity Large Hadron Collider (HL-LHC)
: Preliminary Design Repor
Quench Simulation in an Integrated Design Environment for Superconducting Magnets
The electrical integrity of superconducting magnets that go through a resistive transition (quench) is an important consideration in magnet design. Numerical quench simulation leads to a coupled thermodynamic and electromagnetic problem, due to the mutual dependence of material parameters. While many tools treat the electromagnetic field problem and the thermodynamic one independently, more recent developments adopt a strongly coupled approach in a 3-D finite-element environment. We introduce a computationally efficient weak electromagnetic-thermodynamic coupling within an integrated design environment for superconducting magnet
Modelling nonlinear effects in high temperature superconducting magnets
In the future particle colliders, the accelerator magnets keeping the particles on their tracks are required to produce magnetic fields above 20 T. This can be achieved only by using high temperature superconductors. The technology for producing the high temperature superconducting (HTS) conductors is relatively new and only recently the number of HTS conductor manufacturers has started to increase. It was only in 2016, when a 10 kA class Roebel cable made of REBCO tapes was tested in a small study coil, Feather-M0. Followed by that, in 2017 the first Roebel cable based 5 T accelerator magnet prototype Feather-M2 was constructed and tested to examine the prospects of HTS REBCO technology in accelerator magnets. The measurement results suggested that there is still a lot to learn in modelling those magnets.
This thesis begins by introducing the readers to the mathematical and physical background for understanding the research presented in the attached publications. The background is followed by the chapters reviewing and synthetizing the publications. The focus in this thesis is on the AC loss modelling and thermal stability modelling. First, AC losses and magnetic field quality are modelled in Feather-M0 using a self-implemented minimum magnetic energy variation principle based simulation tool. Then, the focus is moved on the thermal stability modelling of HTS magnets by formulating the thermal model utlized in this thesis work. Next, the thermal model is utilized for scrutinizing the behavior of Feather-M2 with an inverse problem based modelling approach. Using the Feather-M2 measurement data, the inverse problem solutions are obtained for the thermal model parameters characterizing the magnet in terms of the thermal model. Furthermore, the thermal model is utilized and an optimization problem is formulated in order to determine the maximum stable operation current of Feather-M2. Finally, an energy-extraction system (EES) design for 20 T range magnet is presented and optimized by formulating and solving an optimization problem
The Influence of Metal Plates on Quench Protection of High Temperature Superconducting Pancake Coils
Conceptual design of the International Axion Observatory (IAXO)
The International Axion Observatory (IAXO) will be a forth generation axion
helioscope. As its primary physics goal, IAXO will look for axions or
axion-like particles (ALPs) originating in the Sun via the Primakoff conversion
of the solar plasma photons. In terms of signal-to-noise ratio, IAXO will be
about 4-5 orders of magnitude more sensitive than CAST, currently the most
powerful axion helioscope, reaching sensitivity to axion-photon couplings down
to a few GeV and thus probing a large fraction of the
currently unexplored axion and ALP parameter space. IAXO will also be sensitive
to solar axions produced by mechanisms mediated by the axion-electron coupling
with sensitivity for the first time to values of not
previously excluded by astrophysics. With several other possible physics cases,
IAXO has the potential to serve as a multi-purpose facility for generic axion
and ALP research in the next decade. In this paper we present the conceptual
design of IAXO, which follows the layout of an enhanced axion helioscope, based
on a purpose-built 20m-long 8-coils toroidal superconducting magnet. All the
eight 60cm-diameter magnet bores are equipped with focusing x-ray optics, able
to focus the signal photons into cm spots that are imaged by
ultra-low-background Micromegas x-ray detectors. The magnet is built into a
structure with elevation and azimuth drives that will allow for solar tracking
for 12 h each day.Comment: 47 pages, submitted to JINS
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