Optimization design and test of the Booster Ring dipole magnet in HIAF

Abstract

The High-Intensity Heavy Ion Accelerator Facility (HIAF), proposed by the Institute of Modern Physics, Chinese Academy of Sciences (IMP), is being designed to provide primary and radioactive intense beams for nuclear and related research. As an important part of HIAF, the Booster Ring (BRing) is a fast ramping synchrotron and is used to obtain high intensity (238U35+, 1 × 1011 ppp) and high energy (0.835 GeV/u) heavy-ion beam. Moreover, the beam rigidity of the Booster Ring varies widely from 1 Tm to 34 Tm. These require the dipole of Booster Ring to have a large-good field region, a high magnetic field homogeneity, and a wide range of magnetic field variation from 0.047 T to 1.58 T. Aiming at the properties of the dipole magnet, we adopt some new methods to improve magnetic field precision and optimize efficiency. Double symmetrical air holes in the magnet pole are used to guarantee the magnetic field homogeneity under a wide magnetic field range. At the same time, the linear programming algorithm is adopted to optimize the integral magnetic field uniformity of the iron-dominated dipole magnet, which improves the integral magnetic field precision and optimization efficiency. So far, the prototype dipole magnet has been fabricated and tested. Through magnetic field optimization, measurement, and secondary trimming, the measurement results satisfy the physical requirements.