Numerical Optimization of the FFS Quadrupole

Three experiments HIHEX (Heavy Ion Heating and Expansion), LAPLAS (Laboratory Planetary Sciences) and PRIOR (Proton Microscope for FAIR) are proposed by the HED@FAIR (High Energy Density at Facility for Antiproton and Ion Research) collaboration to study matter under extreme conditions of temperature and pressure at the FAIR facility in Darmstadt, Germany. A special beam strong final focusing and imaging system has to be installed at the end of the HED@FAIR beam line. One of the main components of these systems are four wide-aperture quadrupoles, which have to provide a focal spot of about a millimeter size. Within the framework of collaboration between IHEP and GSI at IHEP, these magnets will be designed and produced. The main parameters of the quadrupoles are: DC operating mode; the coil inner diameter is 260 mm; the minimal distance between quadrupole centers of two nearby magnets is 2500 mm; the integral of field gradient is 66 T. The prototype of the quadrupole coil is manufactured and its mechanical characteristics is studied. The 2D and 3D geometry of large-aperture quadrupole is optimized taking into account these studies. The general characteristics of this geometry are presented in this article.