Three dimensional field analysts of helical magnet for RHIC Siberian snake

Siberian Snakes that consist of four helical dipole magnets will be installed in the Relativistic Heavy Ion Collider (RHIC) to preserve the polarization of the proton beam. To promote this project we are collaborating with Brookhaven National Laboratory (BNL) in studying helical magnet designs. At present, two types of helical magnets are being developed. One is being designed by the BNL magnet group, and the other by Advanced Magnet Technology (AML), Inc. These magnets use the same superconducting cable but have different shapes especially in the end regions. We are evaluating the performance of both magnet designs using the three dimensional (3D) magnetic field analysis code TOSCA. In particular, saturation effect, field strength, multipole component and magnet quenching features will be discussed.