1,984 research outputs found
Experimental results and analysis from the 11 T Nb3Sn DS dipole
FNAL and CERN are developing a 5.5-m-long twin-aperture Nb3Sn dipole suitable
for installation in the LHC. A 2-m-long single-aperture demonstrator dipole
with 60 mm bore, a nominal field of 11 T at the LHC nominal current of 11.85 kA
and 20% margin has been developed and tested. This paper presents the results
of quench protection analysis and protection heater study for the Nb3Sn
demonstrator dipole. Extrapolations of the results for long magnet and
operation in LHC are also presented.Comment: 10 pages, Contribution to WAMSDO 2013: Workshop on Accelerator
Magnet, Superconductor, Design and Optimization; 15 - 16 Jan 2013, CERN,
Geneva, Switzerlan
Modeling heat transfer from quench protection heaters to superconducting cables in Nb3Sn magnets
We use a recently developed quench protection heater modeling tool for an
analysis of heater delays in superconducting high-field Nb3Sn accelerator
magnets. The results suggest that the calculated delays are consistent with
experimental data, and show how the heater delay depends on the main heater
design parameters.Comment: 8 pages, Contribution to WAMSDO 2013: Workshop on Accelerator Magnet,
Superconductor, Design and Optimization; 15 - 16 Jan 2013, CERN, Geneva,
Switzerlan
Magnetic Quench Antenna for MQXF Quadrupoles
High-field MQXF-series quadrupoles are presently under development by LARP and CERN for the upcoming LHC luminosity upgrade. Quench training and protection studies on MQXF prototypes require a capability to accurately localize quenches and measure their propagation velocity in the magnet coils. The voltage tap technique commonly used for such purposes is not a convenient option for the 4.2-m-long MQXF-A prototype, nor can it be implemented in the production model. We have developed and tested a modular inductive magnetic antenna for quench localization. The base element of our quench antenna is a round-shaped printed circuit board containing two orthogonal pairs of flat coils integrated with low-noise preamplifiers. The elements are aligned axially and spaced equidistantly in 8-element sections using a supporting rod structure. The sections are installed in the warm bore of the magnet, and can be stacked together to adapt for the magnet length. We discuss the design, operational characteristics and preliminary qualification of the antenna. Axial quench localization capability with an accuracy of better than 2 cm has been validated during training test campaign of the MQXF-S1 quadrupole
A New Scintillator Tile/Fiber Preshower Detector for the CDF Central Calorimeter
A detector designed to measure early particle showers has been installed in
front of the central CDF calorimeter at the Tevatron. This new preshower
detector is based on scintillator tiles coupled to wavelength-shifting fibers
read out by multi-anode photomultipliers and has a total of 3,072 readout
channels. The replacement of the old gas detector was required due to an
expected increase in instantaneous luminosity of the Tevatron collider in the
next few years. Calorimeter coverage, jet energy resolution, and electron and
photon identification are among the expected improvements. The final detector
design, together with the R&D studies that led to the choice of scintillator
and fiber, mechanical assembly, and quality control are presented. The detector
was installed in the fall 2004 Tevatron shutdown and started collecting
colliding beam data by the end of the same year. First measurements indicate a
light yield of 12 photoelectrons/MIP, a more than two-fold increase over the
design goals.Comment: 5 pages, 10 figures (changes are minor; this is the final version
published in IEEE-Trans.Nucl.Sci.
Designing a Magnetic Measurement Data Acquisition and Control System with Reuse in Mind: A Rotating Coil System Example
Accelerator magnet test facilities frequently need to measure different
magnets on differently equipped test stands and with different instrumentation.
Designing a modular and highly reusable system that combines flexibility
built-in at the architectural level as well as on the component level addresses
this need. Specification of the backbone of the system, with the interfaces and
dataflow for software components and core hardware modules, serves as a basis
for building such a system. The design process and implementation of an
extensible magnetic measurement data acquisition and control system are
described, including techniques for maximizing the reuse of software. The
discussion is supported by showing the application of this methodology to
constructing two dissimilar systems for rotating coil measurements, both based
on the same architecture and sharing core hardware modules and many software
components. The first system is for production testing 10 m long
cryo-assemblies containing two MQXFA quadrupole magnets for the high-luminosity
upgrade of the Large Hadron Collider and the second for testing IQC
conventional quadrupole magnets in support of the accelerator system at
Fermilab
Quench Performance of the First Pre-series AUP Cryo-assembly
The High Luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN
will include eight cryo-assemblies that are expected to be fabricated and
delivered to CERN by the US HL-LHC Accelerator Upgrade Project (AUP) as part of
the U.S. contributions to the HL-LHC. These cryostat assemblies are the
quadrupole magnetic components of the HL-LHC Q1 and Q3 inner triplet optical
elements in front of the two interaction points. Each cryo-assembly consists of
two 4.2 m long Nb3Sn quadrupole magnets with aperture 150 mm and operating
gradient 132.6 T/m. The first pre-series cryo-assembly has been fabricated and
successfully tested at the horizontal test facility at Fermi National
Accelerator Laboratory. In this manuscript we report the quench test results of
the LQXFA/B-01 cryo-assembly. The primary objective of the horizontal test is
full cryo-assembly qualification and validation of the performance
requirements.Comment: MT28 International Conference on Magnet Technology, Accepted Versio
Overview of the Quench Heater Performance for MQXF, the Nb3Sn Low-β Quadrupole for the High Luminosity LHC
In the framework of the high-luminosity upgrade of the Large Hadron Collider, the U.S. LARP collaboration and CERN are jointly developing a 150 mm aperture Nb Sn quadrupole for the LHC interaction regions. Due to the large stored energy density and the low copper stabilizer section, the quench protection of these magnets is particularly challenging, relying on a combination of quench heaters attached to the coil surface and coupling loss induced quench (CLIQ) units electrically connected to the coils. This paper summarizes the performance of the quench heater strips in different configurations relevant to machine operation. The analysis is focused on the inner layer quench heaters, where several heater strips failed during powering tests. Failure modes are discussed in order to address the technology issues and provide guidance for future tests.
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Analysis of voltage spikes in superconducting Nb3Sn magnets
Fermi National Accelerator Laboratory has been developing a new generation of superconducting accelerator magnets based on Niobium Tin (Nb{sub 3}Sn). The performance of these magnets is influenced by thermo-magnetic instabilities, known as flux jumps, which can lead to premature trips of the quench detection system due to large voltage transients or quenches at low current. In an effort to better characterize and understand these instabilities, a system for capturing fast voltage transients was developed and used in recent tests of R&D model magnets. A new automated voltage spike analysis program was developed for the analysis of large amount of voltage-spike data. We report results from the analysis of large statistics data samples for short model magnets that were constructed using MJR and RRP strands having different sub-element size and structure. We then assess the implications for quench protection of Nb{sub 3}Sn magnets
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