PIN Photodiodes for Radiation Monitoring and Protection in the BaBar Silicon Vertex Tracker

摘要

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