EicC Collider Lattice Design

The internal structure and strong interaction of hadrons are important frontier subject of common concern in middle and high energy nuclear physics and particle physics.The polarized electron-ion collider is the most effective facility to study the three-dimensional structure,quark gluon distribution and strong interaction in the hadrons.Electron Ion Collider in China(EicC)is being planned to be constructed in China,which is mainly used for sea quark research.The main work of this paper is to design the interaction region optics of proton ring pRing and electronic ring eRing.Interaction region optical design is one of the very important work in the EicC,which is the basis of whether the collider can meet the design requirements.Different from conventional collider,the EicC requires high luminosity,double beam polarization and full accepted detection,which is difficult to design.For this reason,the EicC adopts the asymmetric optical design for the double interaction region,so that the two interaction regions can meet the requirements of full accepted detection and installation of the detector.Then,the interaction model optical design of pRing and eRing was completed by further matching other functional sections such as the two ring arcs,ERL.The collider has strict requirement on chromaticity.The short straight line between pRing adjacent arc cannot provide beta function consistent with arc region,which makes it more difficult to compensate the chromaticity of the pRing.In this paper,by studying the different chromaticity compensation modes of pRing,the chromaticity compensation scheme which includes arc region and short straight line is finally adopted.Moreover,two interaction regions of the Eic C are located in the same long straight section,and the influence of phase shift between them on the dynamic aperture is particularly important.In this paper,the dynamic aperture is optimized by adjusting the phase shift to meet the design requirements.In this paper,the EicC interaction optical design was studied,including interaction region design,interaction region optics design,interaction point beta function value optimization,chromaticity compensation scheme optimization and phase value optimization between interaction points,which lay a foundation for further work of EicC dynamic design.