Fermilab in the framework of the U.S. Magnet Development Program (MDP) has developed a Nb 3 Sn dipole demonstrator for a post-LHC hadron collider. The magnet uses 60-mm aperture 4-layer shell-type ...graded coils. The cable in the two innermost layers has 28 strands 1.0 mm in diameter and the cable in the two outermost layers has 40 strands 0.7 mm in diameter. An innovative mechanical structure based on aluminum I-clamps and a thick stainless steel skin is used to preload Nb 3 Sn coils and support large Lorentz forces. The maximum field for this magnet is limited by 15 T due to mechanical considerations. The first magnet assembly was done with lower coil pre-load to achieve 14 T and minimize the risk of coil damage during assembly. This paper describes the magnet design and the details of its assembly procedure, and reports the results of its cold tests.
Within the U.S. magnet development program, Fermilab is developing a 15-T Nb 3 Sn dipole demonstrator. Prior to the construction of the real magnet model, short sections and the whole structure were ...instrumented with strain gauges and assembled to validate the results of structural analysis, check tooling, and to gain experience with the assembly of the real magnet components. This paper summarizes the lessons learned from these mechanical models and compares the measured data with the finite-element analysis.
In the framework of the U.S. Magnet Development Program (MDP), Fermilab has developed and tested a high-field Nb 3 Sn dipole demonstrator MDPCT1 for a post-LHC Hadron Collider. The magnet was first ...assembled with a lower coil pre-load to minimize the risk of coil damage during assembly and test. In the first test the magnet reached its test goal producing a world record field of 14.1 T at 4.5 K. Next the magnet was reassembled with nominal pre-load to achieve its design field limit of 15 T. This paper describes the details of MDPCT1 inspection, design modifications and reassembly. The magnet quench performance, including training, ramp rate and temperature dependences in the temperature range of 1.9-4.5 K, is presented and discussed.
The HL-LHC interaction region magnet triplets (Q1, Q2, and Q3) will be composed of superconducting Nb 3 Sn quadrupoles. The MQXF quadrupole protection system is based on CLIQ (Coupling-Loss Induced ...Quench system) and outer layer quench heaters. This paper reports a summary of quench heaters to coil high voltage tests performed on MQXF short and long coils in air after fabrication, and in air and He gas after magnet training. Breakdown voltage values demonstrate good margin with respect to the Electrical design criteria for the HL-LHC inner triplet magnets. A modification in the quench heater installation- with an extra layer of fiber glass between the coil and the quench heater trace- has been proposed and tested in a mirror magnet to further increase electrical margins. Results demonstrated improvements of high voltage margin at the expense of a clear increase of hot spot temperature. The baseline heater to coil insulation was assessed to be able to guarantee safe operation for the Nb 3 Sn quadrupole magnets for the interaction regions of HL-LHC.
The goal of the Mu2e experiment at Fermilab is to search for charged-lepton flavor violation by looking for neutrino-less muon to electron conversion in the field of the nucleus. The Mu2e ...experimental apparatus utilizes a complex magnetic field in the muon generation and momentum and charge selection process. Precise knowledge of the magnetic field is crucial. It is planned to map the solenoid field with calibrated three-dimensional (3-D) Hall probes up to 10 -5 accuracy. This article describes a new design of a Hall probe calibration system that will be used to calibrate 3-D Hall probes to better than 10 -5 accuracy for the Mu2e solenoid field mapping system.
Mu2e Solenoid Field Mapping System Design Feher, Sandor; DeLurgio, Patrick; Elementi, Luciano ...
IEEE transactions on applied superconductivity,
04/2018, Letnik:
28, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The Mu2e experiment at Fermilab plans to search for charged-lepton flavor violations by looking for neutrino-less muon to electron conversions in the field of the nucleus. A complex solenoid system ...and precise knowledge of its magnetic field play a major role in the experimental approach Mu2e has chosen. It is essential to map the solenoid field up to 10 -4 accuracy. This article describes the design of the Field Mapping System Mu2e will use to measure the magnetic field. Two different mechanical mapper systems, a survey-based position determination of the in-house calibrated three-dimensional Hall probes, a motion control system, and a data acquisition and readout system are presented.
The presence of immune-mediated hearing loss was investigated in an animal model. Eight guinea pigs and four mice underwent immunizations with a preparation of chick or guinea pig cochlear tissue and ...Freund's adjuvant. Hearing thresholds were monitored by auditory brainstem response (ABR) testing over a 5-week period after immunization. The serum and temporal bones of test and control animals were then examined using an enzyme-linked immunosorbent assay (ELISA), immunocytochemical, and histological techniques. Hearing loss of 20 dB or greater occurred in eight animals. ELISA demonstrated antibodies to cochlear antigens in the sera of all test animals. Immunocytochemistry revealed immunostaining of hair cell stereocilia in the organ of Corti and saccule. Endolymphatic hydrops, and organ of Corti degeneration was observed in the temporal bones of three animals. This study provides evidence to suggest that cross-species immunization with cochlear antigens might produce a humoral response that can be associated with inner ear pathologic change and sensorineural hearing loss.
The relationships between the levels of transcripts and the levels of the proteins they encode have not been examined comprehensively in mammals, although previous work in plants and yeast suggest a ...surprisingly modest correlation. We have examined this issue using a genetic approach in which natural variations were used to perturb both transcript levels and protein levels among inbred strains of mice. We quantified over 5,000 peptides and over 22,000 transcripts in livers of 97 inbred and recombinant inbred strains and focused on the 7,185 most heritable transcripts and 486 most reliable proteins. The transcript levels were quantified by microarray analysis in three replicates and the proteins were quantified by Liquid Chromatography-Mass Spectrometry using O(18)-reference-based isotope labeling approach. We show that the levels of transcripts and proteins correlate significantly for only about half of the genes tested, with an average correlation of 0.27, and the correlations of transcripts and proteins varied depending on the cellular location and biological function of the gene. We examined technical and biological factors that could contribute to the modest correlation. For example, differential splicing clearly affects the analyses for certain genes; but, based on deep sequencing, this does not substantially contribute to the overall estimate of the correlation. We also employed genome-wide association analyses to map loci controlling both transcript and protein levels. Surprisingly, little overlap was observed between the protein- and transcript-mapped loci. We have typed numerous clinically relevant traits among the strains, including adiposity, lipoprotein levels, and tissue parameters. Using correlation analysis, we found that a low number of clinical trait relationships are preserved between the protein and mRNA gene products and that the majority of such relationships are specific to either the protein levels or transcript levels. Surprisingly, transcript levels were more strongly correlated with clinical traits than protein levels. In light of the widespread use of high-throughput technologies in both clinical and basic research, the results presented have practical as well as basic implications.
PDF
