Design and B-field measurements of a Lambertson injection magnet for the RHIC machine

Two Lambertson-type injection magnets have been designed, constructed and tested magnetically. One magnet is the mirror image of the other and each will serve as an injector in the rings of the Relativistic Heavy Ion Collider (RHIC) accelerators under construction at Brookhaven National Laboratory (BNL). To obtain the required field quality in the injected beam region and low stray fields in the circulating beam region of the magnet, an optimization study was performed using computer codes to provide solutions for a two and three dimensional model of the magnet. The calculations are compared to the magnetic field measurements taken in the injected and circulating beam regions mentioned above. Field inhomogeneities in the injected beam region were less than 6×10^-4 for either measured or calculated B-fields. The magnetic-field strength in the circulating beam region was less than 0.1 Gauss (measured or calculated). A description of the mechanical design of the magnet as well as a detailed comparison of the measured magnetic fields to these calculated using the two and three dimensional computer codes is presented here