Fermi National Accelerator Laboratory (Fermilab) is currently constructing a new High Field Vertical Magnet Test Facility (HFVMTF) designed for testing High Temperature Superconducting (HTS) cables ...under high magnetic fields. This facility is expected to offer capabilities similar to those of EDIPO at PSI and FRESCA2 at CERN. The background magnetic field of 15 T will be generated by a magnet supplied by Lawrence Berkeley National Laboratory. The primary function of HFVMTF will be to serve as a superconducting cable test facility, facilitating tests under high magnetic fields and a broad spectrum of cryogenic temperatures. Additionally, the facility will be utilized for testing high-field superconducting magnet models and demonstrators, including hybrid magnets, developed by the US Magnet Development Program (MDP). This paper provides a comprehensive description of the current status of two pivotal components of the facility: the Top/Lambda Plates Assembly and the Anticryostat for the Test Sample Holder. The latter will serve as a principal interface component connecting cable test samples with the facility's cryostat.
In the past ten years, Fermilab has been executing an intensive R&D program on accelerator magnets based on Nb 3 Sn superconductor technology. This R&D effort includes dipole and quadrupole models ...for different programs, such as LARP and 11 T dipoles for the LHC high-luminosity upgrade. Before the Nb 3 Sn R&D program, Fermilab was involved in the production of the low-beta quadrupole magnets for LHC based on the NbTi superconductor. Additionally, during the 2003-2005 campaign to optimize the operation of the Tevatron, a large number of Tevatron magnets were remeasured. As a result of this field analysis, a systematic study of the persistent current decay and snapback effect in these magnets was performed. This paper summarizes the result of this study and presents a comparison between Nb 3 Sn and NbTi dipoles and quadrupoles.
Abstract
The United States has a rich history in high energy particle
accelerators and colliders — both lepton and hadron machines,
which have enabled several major discoveries in elementary particle
...physics. To ensure continued progress in the field, U.S. leadership
as a key partner in building next generation collider facilities
abroad is essential; also critically important is to prepare to host
an energy frontier collider in the U.S. once the construction of
the LBNF/DUNE project is completed. In this paper, we briefly
discuss the ongoing and potential U.S. engagement in proposed
collider projects abroad and present a number of future collider
options we have studied for hosting an energy frontier collider in
the U.S. We also call for initiating an integrated national R&D
program in the U.S. now, focused on future colliders.
Rotating coil probes are essential for measuring harmonic multipole fields of accelerator magnets. A fundamental requirement of these probes is their accuracy, which typically implies that the probes ...need to be very stiff and straight, have highly accurate knowledge of the placement of windings, and an ability to buck the fundamental fields well in order to suppress the effects of vibrations. Ideally, for an R&D test environment, probe fabrication should also be easy and low-cost, so that probe parameters (type, length, number of turns, radius, etc.) can be customized to the magnet requiring test. Such facility allows measurement optimization for magnets of various multipolarity, aperture size, cable twist pitch, etc. The accuracy and construction flexibility aspects of probe development, however, are often at odds with each other. This paper reports on application of printed-circuit board and fused-deposition modeling technologies, and what these offer to the fabrication of magnetic measurement probe systems.
Persistent magnetization currents are induced in superconducting filaments during the current ramping in magnets. The resulting perturbation to the design magnetic field leads to field quality ...degradation, particularly at low field, where the effect is stronger relative to the main field. The effects observed in NbTi accelerator magnets were reproduced well with the critical-state model. However, this approach becomes less accurate for the calculation of the persistent-current effects observed in Nb 3 Sn accelerator magnets. Here, a finite-element method based on the measured strand magnetization is validated using three state-of-the-art Nb 3 Sn accelerator magnets featuring different subelement diameters, conductor critical currents, magnet designs, and test temperatures. The temperature dependence of the persistent-current effects is reproduced. Based on the validated model, the impact of conductor design on the persistent-current effects is discussed. The strengths, limitations, and possible improvements of the approach are also discussed.
The research analyses some possibilities for automated processing of data from measuring the nondestructive testing characteristics: thermo-electromotive force (
E
MF
) and magnetic noise (MN), also ...known as Barkhausen noise (NB), represented respectively by the parameters: thermo-electromotive voltage ET and magnetic noise voltage
E
NB
, in samples of metals and alloys. Mathematical algorithms for developing software for an automated system for evaluating the test results are presented. Two statistical methods for classifying groups of samples and products according to measured values of
E
T
and
E
NB
, when sorting by grade (chemical composition) and heat treatment (hardness) of structural steels were investigated—cluster analysis and robust (stable) evaluations, which are suitable for data processing with high dispersion.
Fermi National Accelerator Laboratory (Fermilab) fabricated the torus magnet coils for the 12-GeV Hall B upgrade at Jefferson Lab (JLab). The production consisted of six large superconducting coils ...for the magnet and two spare coils. The toroidal field coils are approximately 2 m × 4 m × 5 cm thick. Each of these coils consists of two layers, each of which has 117 turns of copper-stabilized superconducting cable, which will be conduction cooled by supercritical helium. Due to the size of the coils and their unique geometry, Fermilab designed and fabricated specialized tooling and, together with JLab, developed unique manufacturing techniques for each stage of the coil construction. This paper describes the tooling and manufacturing techniques required to produce the six production coils and the two spare coils needed by the project.
We describe a technique for dynamic quantum optical arbitrary-waveform generation and manipulation, which is capable of mode selectively operating on quantum signals without inducing significant loss ...or decoherence. It is built upon combining the developed tools of quantum frequency conversion and optical arbitrary waveform generation. Considering realistic parameters, we propose and analyze applications such as programmable reshaping of picosecond-scale temporal modes, selective frequency conversion of any one or superposition of those modes, and mode-resolved photon counting. We also report on experimental progress to distinguish two overlapping, orthogonal temporal modes, demonstrating over 8 dB extinction between picosecond-scale time-frequency modes, which agrees well with our theory. Our theoretical and experimental progress, as a whole, points to an enabling optical technique for various applications such as ultradense quantum coding, unity-efficiency cavity-atom quantum memories, and high-speed quantum computing.
The paper attempts to outline the security issues in the development and application of cloud-based mobile learning. A brief definition of the mobile learning, its components and related technologies ...and devices is given. The specific characteristics of social media, big data and cloud computing are summarized in relation with their integration in the mobile learning and its transformation to a cloud-based environment. The main security threats to this type of learning are pointed out and some recommendations for providing security learning are given are given.
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