Polarized pp physics with internal jet targets at RHIC

The physics scope of RHIC could be extended to include fixed target experiments by the addition of a gas jet target. Two applications stand out among many possibilities. RHIC is the first accelerator to provide polarized proton beams with energy above 30 GeV. Extensive studies of pp colliding beams are planned for RHIC, but these will not cover the energy range covered with a fixed target, where the scattering of polarized protons from protons has not been adequately studied. Another important application is the possible use of a hydrocarbon jet to obtain a rapid and precise measurement of the polarization of the RHIC proton beams. A gas jet target with associated recoil detectors, electronics, and vacuum pumps is available and can be installed with low incremental costs on a short time scale.