Test Results for the Electron Lens Superconducting Magnets at RHIC

In order to partially compensate for head-on beam-beam effects from polarized proton collisions in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL), two electron lenses (e-Lens) have been manufactured at BNL. For each e-Lens, one for each of the two RHIC rings, a low energy electron beam and the high energy proton beam will interact in a 2.5-m-long superconducting solenoid, which is also accompanied by four other smaller solenoids and 12 corrector dipoles, all of which are superconducting and provide various tuning and corrective functions during operations. The design of this multicoil assembly is a unique and complex one, and likewise, the simultaneous operation of the coils at 4.5 K is also challenging, due to high inductance and individual magnetic fields, which interact with each other. This paper reports on the results from extensive ramp and quench tests at 4.5 K, and the proper operating procedures determined from these tests.