BEPCII Interaction Region Design and Construction Status

BEPC (Beijing Electron Positron Collider) is now upgrading to a double-ring collider which requires a new storage ring to be built in the existing tunnel. A new and compact interaction region (IR) has been designed to allow a peak luminosity of 10³³cm^-2s^-1from an equal beam energy of 1.89 GeV, a crossing angle, 93 bunches with maximum beam current of 0.91 A . The multi-purpose superconducting magnets and conventional dual aperture quadrupoles are used as final focusing quadrupole in the interaction region. The two beams collide at the interaction point with a crossing angle of ± 11 mrad and further beams separation is enhanced with the help of a septum bending magnet which locates just beyond the superconducting magnet and acts on the outgoing beam lines only. This paper will describe the IR design and the construction status.