U.S. LARP Magnet program

Progress and plans for the U.S. LARP R&D work are summarized. Results to date for work on materials and model magnets are presented in more detail

Genomic Relationships, Novel Loci, and Pleiotropic Mechanisms across Eight Psychiatric Disorders

Genetic influences on psychiatric disorders transcend diagnostic boundaries, suggesting substantial pleiotropy of contributing loci. However, the nature and mechanisms of these pleiotropic effects remain unclear. We performed analyses of 232,964 cases and 494,162 controls from genome-wide studies of anorexia nervosa, attention-deficit/hyper-activity disorder, autism spectrum disorder, bipolar disorder, major depression, obsessive-compulsive disorder, schizophrenia, and Tourette syndrome. Genetic correlation analyses revealed a meaningful structure within the eight disorders, identifying three groups of inter-related disorders. Meta-analysis across these eight disorders detected 109 loci associated with at least two psychiatric disorders, including 23 loci with pleiotropic effects on four or more disorders and 11 loci with antagonistic effects on multiple disorders. The pleiotropic loci are located within genes that show heightened expression in the brain throughout the lifespan, beginning prenatally in the second trimester, and play prominent roles in neurodevelopmental processes. These findings have important implications for psychiatric nosology, drug development, and risk prediction.Peer reviewe

Design and Fabrication of the 1.9 K Magnet Test Facility at BNL, and Test of the First 4-m-Long MQXF Coil

The future high luminosity upgrade of the Large Hadron Collider (LHC) at CERN will include 20 4.2-m-long Nb$_3$Sn high gradient quadrupole magnets, which will be components of the triplets for two LHC insertion regions. In order to test these and four preproduction models, the vertical superconducting magnet test facility of the Superconducting Magnet Division (SMD) at Brookhaven National Laboratory (BNL) has been upgraded to perform testing in superfluid He at 1.9 K and 1 bar, the operational condition at the LHC. This has involved extensive modification of the 4.5 K cryogenics plant, including piping, compressors, and other upgraded components; a new vertical test cryostat, which can accept larger diameter magnets; a modernized power supply system upgraded with IGBT switches and fast shutoff capability, and that can supply 24 kA to test high field Nb$_3$Sn magnets; and completely new data acquisition, signal analysis, and control software and hardware, allowing for fast, high precision, large volume data collection. This paper reports on the design, assembly, and commissioning of this upgraded test facility, and presents results of the first magnet test performed

Analysis of Nb3Sn Accelerator Magnet Training

Nb$_3$Sn accelerator magnet technology has made significant progress during the past decades. For the first time, it is planned to be used in a real accelerator. A relatively small number of Nb$_3$Sn quadrupoles and dipoles will be installed in the LHC to increase machine luminosity. Although it will prove the possibility of using Nb$_3$Sn magnets in real machines, many questions of scaling this technology up remain. One of them is related to slow training of Nb$_3$Sn magnets compared to the traditional Nb-Ti accelerator magnets. Since the goal is to operate thousands of Nb$_3$Sn magnets in a future post-LHC accelerator, the slow training will affect both the practical design margin and the nominal operation field. Consequently, the cost of the project to reach the design field level is also increased. To improve our understanding of slow magnet training the existing Fermilab data from Nb$_3$Sn magnet tests we reanalyzed. A summary of coil training features and correlations with fabrication parameters observed is presented in this paper

Low Field NMR Probe Commissioning In LEReC Energy Spectrometer

International audienceLow Energy RHIC electron Cooling (LEReC) is planned during a 7.7 - 20 GeV/n run with Au+79 starting in 2019 (200 GeV/n center-of-mass typical), to explore the existence and location of the QCD critical point. An electron accelerator for LEReC is being constructed to provide a beam to cool both the blue & yellow RHIC ion beams by co-propagating a 10 - 50 mA electron beam of 1.6 - 2.7 MeV. For effective cooling of the ion beam, the electron and ion beam energies must be matched with 10⁻⁴ accuracy. As the energy of the RHIC ion beam can be known to <1×10-4, the absolute energy of the electron beam must also be measured to 10-4 accuracy. A 180° bend transport magnet will be used as an energy spectrometer for the electron beam providing fields in the range of 180 - 325 gauss. A Nuclear Magnetic Resonance (NMR) gaussmeter has been customized to measure the field in the magnet (to as low as 143 gauss) with an accuracy of 50 milligauss and a noise floor of < 20 milligauss. The concept of the magnetic spectrometer and details and commissioning performance of the NMR instrument are presented in this paper