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

TL;DR

This paper presents a radiation monitoring and protection system using PIN photodiodes for the BaBar Silicon Vertex Tracker, effectively safeguarding the detector from radiation damage and aiding in background analysis.

Contribution

It introduces a novel radiation monitoring system with real-time protection capabilities using PIN photodiodes in a high-energy physics experiment.

Findings

System reliably protected the SVT from radiation damage.

Provided real-time radiation dose measurements and diagnostics.

Enabled automatic beam aborts when thresholds were exceeded.

Abstract

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.