33 research outputs found
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 NbSn
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 NbSn 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
Status of the 25 T, 100 mm Bore HTS Solenoid for an Axion Dark Matter Search Experiment
This paper presents the design and test results of the pancake coils for the 25 T, 100 mm bore solenoid that Brookhaven National Laboratory (BNL) is building for the Insti-tute for Basic Science (IBS) in Korea for an Axion dark matter search. The design is based on second generation (2G) High Temperature Superconducting (HTS) tape with no-insulation winding. The major challenges in the high field, large aperture solenoid are the large stresses and the quench protection. Moreo-ver, the design should be robust for reliable operation in a user facility environment. The paper will also present the construction and test results of two âŒ100 mm bore double pancake coils creat-ing a peak field of up to âŒ17 T and similar hoop stresses as will be in the 25 T solenoid. The coils were subject to several severe tests, including the simulations of large defects and extended quench studies at âŒ4 K. The most striking part of these studies was the demonstration of how fast (a few hundred milliseconds) these coils can turn from the superconducting state to the normal state (quench or thermal runaway). This removes the past concerns of protecting high field HTS coils because of the low quench propa-gation velocities. © 2019 IEEE
Assessment of MQXF Quench Heater Insulation Strength and Test of Modified Design
The HL-LHC interaction region magnet triplets (Q1,Q2, and Q3) will be composed of superconducting Nb3Sn quadru-poles. 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 marginwith respect to the Electrical design criteria for the HL-LHC inner triplet mag-nets. A modification in thequench heater installation-with an ex-tra 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.Thebaseline heater to coil insulation was assessed to be able to guarantee safe operation for the Nb3Sn quadrupole mag-nets for the interaction regions of HL-LHC.The HL-LHC interaction region magnet triplets (Q1, Q2, and Q3) will be composed of superconducting Nb3Sn 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 Nb3Sn quadrupole magnets for the interaction regions of HL-LHC
Magnetic Field Measurements of First Pre-series Full-Length 4.2 m Quadrupole MQXFA03 Using PCB Rotating Coils for the Hi-Lumi LHC Project
The U.S. Hi-Lumi LHC Accelerator Upgrade Project (AUP) and CERN have joined efforts to develop high field quadrupoles for the Hi-Lumi LHC upgrade. The US national laboratories in the AUP project will deliver 10 magnets and each cryostat has two 4.2 m high gradient quadrupoles in it. These magnets are made of Nb3Sn conductors, with large aperture (150Â mm) and integrated gradient of 556.9 T. This paper reports on magnetic measurements performed during the vertical test at Brookhaven National Laboratory (BNL) in 2019-2020. A warm measurement Z-Scan (+/â15 A) with 42 Z-positions before cool-down was performed at BNL. The results were directly compared to field data measured at LBNL during magnet assembly. Measured harmonics and magnetic center offsets (ÎX and ÎY) have provided timely and informative diagnostics on the magnet structure's shape at both warm and cold temperatures. A new centering fixture was designed and added to better center the warm bore tube which contains the rotating coil probe. After the quench training to 16.47Â kA was achieved, a complete set of cold measurements (Z-Scan at 16.47Â kA and I-Scan from 960 A to 16.47Â kA and back to 960 A) was made. Periodic axial variation of allowed and nonallowed harmonics was observed which is related to the coil radial and/or mid-plane variations along the magnet axis. Overall, the average harmonics in the straight section are within the required field boundaries.The U.S. Hi-Lumi LHC Accelerator Upgrade Project (AUP) and CERN have joined efforts to develop high field quad-rupoles for the Hi-Lumi LHC upgrade. The US national laborato-ries in the AUP project will deliver 10 magnets and each cryostat has two 4.2 m high gradient quadrupoles in it. These magnets are made of Nb3Sn conductors, with large aperture (150 mm) and in-tegrated gradient of 556.9 T. This paper reports on magnetic measurements performed during the vertical test at Brookhaven National Laboratory (BNL) in 2019-2020. A warm measurement Z-Scan (+/- 15 A) with 42 Z-positions before cool-down was per-formed at BNL. The results were directly compared to field data measured at LBNL during magnet assembly. Measured harmonics and magnetic center offsets (ÎX and ÎY) have provided timely and informative diagnostics on the magnet structureâs shape at both warm and cold temperatures. A new centering fixture was de-signed and added to better center the warm bore tube which con-tains the rotating coil probe. After the quench training to 16.47 kA was achieved, a complete set of cold measurements (Z-Scan at 16.47 kA and I-Scan from 960 A to 16.47 kA and back to 960 A) was made. Periodic axial variation of allowed and nonallowed harmonics was observed which is related to the coil radial and/or mid-plane variations along the magnet axis. Overall, the average harmonics in the straight section are within the required field boundaries