At Brookhaven he oversaw the high intensity beam development at the Alternating Gradient Synchrotron (AGS) and led the effort to accelerate polarized protons in the AGS using compact partial Siberian snakes. Starting in 1999 he led the commissioning of the Relativistic Heavy Ion Collider (RHIC) and the development of polarized proton acceleration, resulting in the first 250 GeV on 250 GeV polarized proton collisions in RHIC.