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LQXFA/B production series cryogenic assemblies are being built for the LHC upgrade by the HL-LHC Accelerator Upgrade Project (AUP). These contain a pair of MQXFA quadrupole magnets combined as a cold mass within a vacuum vessel, and are to be installed in the IR regions of the LHC. The LQXFA/B are being tested at 1.9 K to assess alignment and magnetic performance at Fermilab's horizontal test facility. The ∼10 m long assembly must meet stringent specifications for quadrupole strength and harmonic field integrals determination, magnetic axis location, and for variations in axis position and local field profiles. A multi-probe, PCB-based rotating coil and a Single Stretched Wire system are employed for these measurements. To accurately determine rotating coil location and angles within the cold mass, a laser tracker is utilized to record multiple targets at one end of the probe. This paper describes the measurements, probes/equipment, and techniques used to perform the necessary characterization of the cold mass.

The U.S. High-Luminosity LHC Accelerator Upgrade Project (HL-LHC AUP) is developing MQXFA magnets, a series of 4.5 m long 150 mm aperture high-field Nb$_{3}$Sn quadrupole magnets for the HL-LHC upgrade at CERN. Five pre-series magnets, MQXFA03 through MQXFA07, have been developed. During the magnet assembly stage, we perform magnetic measurements on the coil-pack sub-assembly and magnets after loading to track the field quality for two purposes. First, it serves as a quality assurance tool to check if the magnet field quality is on track to meet the acceptance criteria. Magnetic measurements are used to understand if magnetic shims are needed to compensate low-order field errors and to meet the field quality targets. Second, the measurements during the assembly stage can also help understand the field quality, especially the geometric field errors, for Nb$_{3}$Sn accelerator magnets. Here we summarize the measurement results of the pre-series MQXFA magnets, including the magnetic axis and twist angle. The results will provide useful feedback for the series production of Nb$_{3}$Sn magnets and on the optimization of field quality of accelerator magnets based on the wind-and-react Nb$_{3}$Sn technology.

A correlation between the variation of the intrinsic fusion barrier with incident energy and the measured excitation function of fusion-evaporation residue cross-section has been obtained for the reactions: 48 Ca + 238 U → 112 286 Cn ∗ , 48 Ca + 242 Pu → 114 290 Fl ∗ , and 48 Ca + 243 Am → 115 291 Mc ∗ . The maximum value of the measured fusion-evaporation residue cross-section corresponds to the incident energy which is either equal to or within ± 5 MeV of the incident energy for which the intrinsic fusion barrier is minimum. The optimum energy estimates obtained for undiscovered superheavy elements formed in reactions 51 V + 248Cm → 299119* and 50Ti + 249Cf → 299120* are 233.20 MeV and 224.82 MeV, respectively. These estimates agree with the one available in the literature, e.g., the optimum energies for 299119* are 234.8 ± 1.8 MeV and 237 MeV, and for 299120* is 225 MeV. [ABSTRACT FROM AUTHOR]