System Testing and Installation of the NHMFL/NSCL Sweeper Magnet

Abstract

A superconducting dipole, designed for use as a sweeper magnet in nuclear physics experiments, has been designed and built by the National High Magnetic Field Laboratory for operation at the National Superconducting Cyclotron Laboratory. The magnet operates at a peak field of 3.8 T in a 140 mm gap. A secondary beam enters the magnet from the upstream side before striking a target. The neutrons continue straight through to a neutron detector. The charged particles are swept 40 degrees on a one-meter radius into a particle spectrometer. To allow space for the exit of the downstream neutron beam, the magnet iron and coil structure are built in a modified "C" configuration. There are two coils of "D" shape, one above and one below the beam. This configuration keeps the magnet compact and removes the need for a negative curvature side. The peak field in the winding is 6.5 T. The net force on the curved leg of a single "D" is 1.6 MN. Results of system testing including cool-down, quench history, and integration with the cyclotron are presented.

Search for 21C and constraints on 22C

“…The flight path length from the A1900 to the target position was 11.6 m. Neutron unbound isotopes produced in the reaction target immediately decayed into charged fragments and one or more neutrons. A large-gap superconducting dipole magnet [18] bent the charged fragments away from the beam axis, and the neutrons were detected near zero degrees by the Modular Neutron Array (MoNA) [19].…”

Exploring the Low-ZShore of the Island of Inversion atN=19

“…The technique of invariant mass spectroscopy has been used to measure, for the first time, the ground state energy of neutron-unbound 28 F, determined to be a resonance in the 27 F + n continuum at 220(50) keV. States in 28 F were populated by the reactions of a 62 MeV/u 29 Ne beam impinging on a 288 mg/cm 2 beryllium target.…”

Neutron knockout ofBe12populating neutron-unbound states inBe11Peters1, Baumann2, Brown3 et al. 2011Phys. Rev. CSelf Cite142192View full textAdd to dashboardCite

“…Charged particles were deflected by the large gap Sweeper magnet [14,15] and the neutrons were detected by MoNA [9,10]. The setup and the charged-particle detectors after the Sweeper magnet are described in Figure 4 of Ref.…”