DIRC, the Internally Reflecting Ring Imaging Cherenkov Detektor for BaBar: Properties of the Quartz Radiators

TL;DR

The paper discusses the DIRC Cherenkov detector's design, principles, and properties of its quartz radiators, including optical performance and radiation damage, for particle identification in the BaBar experiment.

Contribution

It provides detailed measurements of the optical properties and radiation damage of synthetic fused silica radiators used in the DIRC detector.

Findings

Radiators exhibit stable optical properties under radiation

Radiation damage effects are characterized and manageable

Design choices optimize Cherenkov imaging performance

Abstract

The DIRC is a Cherenkov imaging detector based on total internal reflection for the BaBar detector at PEP-II. The principles of the DIRC ring imaging Cherenkov technique are explained and its choice for the BaBar detector particle identification system is motivated. The detector design and the status of the R&D are discussed. Results of the measurement of the optical properties and radiation damage of the the radiators, long rectangular bars made of synthetic fused silica, are presented.