Baogui Yin

Research and Development of the AC Magnets for CSNS/RCS

Chinese Spallation Neutron Source (CSNS) is a facility planned to be built in China in the coming years. It is composed of 80 MeV Linac, 1.6 GeV Rapid Cycling Synchrotron (RCS) and target station. To accelerate the proton beam from 80 MeV to 1.6 GeV, the RCS requires the field of dipole and quadrupole magnets to change with sine waveform of 25 Hz plus a biased DC. For large amplitude AC magnets with large aperture, there are critical issues to be addressed, such as eddy current induced in the magnet yoke, coils and endplates, vibration of the yoke and coil, field tracking between dipoles and quadrupoles, and so on. To study these issues, one prototype dipole magnet and one prototype quadrupole magnet have been developed and tested. In this paper, the design, fabrication and tests of the two magnets will be described.

Harmonic Coil Design, Fabrication and Commissioning for European XFEL Linear Accelerator Superconducting Magnets Field Measurements

A harmonic coil assembly for the European XFEL superconducting magnet measurements was designed and fabricated in IHEP. Bare coil without protection tube was selected in order to save space and cover a larger measurement radius. The coil assembly can be moved along the anticryostat pipe and can be fixed at any position by rubber brakes touching on the inner surface of the pipe, which is a part of the magnet measurement dewar. The magnetic field can be measured by rotating the coil inside the anticryostat pipe at a selected position. The superconducting magnet package consists of a quadrupole, a horizontal and a vertical dipole. The harmonic coil includes a main coil for the quadrupole and for the dipole field measurement when the single coil mode is used to measure the main field component. Two bucking coils are available to compensate the quadrupole and dipole field respectively when the two-coil mode is used to measure the high order field harmonics. A skew coil with only 2 turns and open angle of 90 degrees can be used to cancel effects due to the angular differences between the main coil plane and the bucking coil plane. The harmonic coil was tested on quadrupoles for Korea Pohang Accelerator Laboratory (PAL), a high bucking ratio of 182 was reached. The coil was shipped and used in DESY to measure the XFEL superconducting magnets. The measurement precision and reproducibility were excellent and the driving and brake system worked well.

Magnetic Field Measurement of the Quadrupole and Sextupole Magnets for HLS-II Storage Ring

The Hefei Light Source upgrade project (HLS-II) contains 8 dipoles, 32 quadrupoles (2 spares), and 32 sextupoles (2 spares) for the storage ring. Magnets were manufactured and magnetic measurements were performed in collaboration with the Institute of High Energy Physics (IHEP), China. Magnet production and validation measurements were finished in December of 2012. Measurements for all quadrupole and sextupole magnets were performed using a harmonic coil magnetic measurements system. This paper describes the magnets and the measurement system and presents results for the integrated field strength, higher order multipole components, offsets between the mechanical and magnetic centers, and the effective length of the multipole magnets.