  We discuss the design, implementation and performance of the radiation
monitoring and protection system used by the Silicon Vertex Tracker (SVT) in
the BaBar detector. Using 12 reverse-biased PIN photodiodes mounted around the
beampipe near the IP, we are able to provide instantaneous radiation dose
rates, absorbed dose integrals, and active protection that aborts the
circulating beams in the PEP-II storage ring when radiation levels exceed
user-defined thresholds. The system has reliably protected the SVT from
excessive radiation damage and has also served as a key diagnostic tool in
understanding radiation backgrounds at PEP-II.
