Evaluation and compensation of detector solenoid effects in the JLEIC

The JLEIC detector solenoid has a strong 3 T field in the Interaction Region (IR) area with a big crossing angle of 50 mrad. One of the main effects of the solenoid field is coupling of the horizontal and vertical betatron motions which must be corrected in order to preserve the dynamical stability and beam spot size match at the Interaction Point (IP). Additional effects include influence on the closed orbit and dispersion caused by the crossing angle between the solenoid axis and the ion beam orbit. Another important aspect of the solenoid is that it affects ion polarization breaking the figure-8 spin symmetry. Crab dynamics further complicates the picture. All of these effects have to be compensated or accounted for. The proposed correction system is equivalent to the Rotating Frame Method. However, it does not involve physical rotation of elements. It provides local compensation of the solenoid effects independently for each side of the IR. It includes skew quadrupoles, dipole correctors and anti-solenoids to cancel perturbations to the orbit and linear optics. The skew quadrupoles and final focus quadrupoles together generate an effect equivalent to adjustable rotation angle to do the decoupling task. Details of all of the correction systems are presented.