HEAD-ON BEAM-BEAM COMPENSATION WITH ELECTRON LENSES IN THE RELATIVISTIC HEAVY ION COLLIDER

The working point for the polarized proton run in the Relativistic Heavy Ion Collider is constrained between 2/3 and 7/10 in order to maintain good beam lifetime and polar- ization. To further increase the bunch intensity to improve the luminosity, a low energy Gaussian electron beam, or an electron lens is proposed to head-on collide with the pro- ton beam to compensate the large tune shift and tune spread generated by the proton-proton beam-beam interactions at IP6 and IP8. In this article, we outline the scheme of head- on beam-beam compensation in the RHIC and give the lay- out of e-lens installation and the parameters of the proton and electron beams. The involved physics and engineering issues are shortly discussed.