D. McShurley

TEST OF A LARGE SCALE PROTOTYPE OF THE DIRC, A CHERENKOV IMAGING DETECTOR BASED ON TOTAL INTERNAL REFLECTION FOR BABAR AT PEP-II

Abstract The principles of the DiRC ring imaging Cherenkov technique are briefly explained and its choice for the B a B ar detector particle identification system is motivated. A large scale prototype of the DIRC for the B a B ar experiment is then described. Details of the design of this prototype and its test in a hadronic particle beam at the CERN-PS are presented, and results from various prototype and test configurations are given. For example, after correcting for geometrical acceptance and estimated collection effects, the number of photoelectrons was measured to be 146 ± 1.8 ± 9 cm −1 , for a track angle of 20° at zero photon transmission distance. The effective attenuation loss was measured to be 4.1 ± 0.7% per meter of bar length, and the observed single photon resolution was 10.0 ± 0.2 mrad. This performance is consistent with what was expected from earlier tests and Monte Carlo simulations, and will be fully adequate for the physics demands of the B a B ar experiment.

A sonar-based technique for the ratiometric determination of binary gas mixtures☆

Abstract We have developed an inexpensive sonar-based instrument to provide a routine on-line monitor of the composition and stability of several gas mixtures having application in a Cherenkov Ring Imaging Detector. The instrument is capable of detecting small (

DIRC, the internally reflecting ring imaging Cherenkov detector for BABAR

The DIRC is a new type of Cherenkov imaging device that will be used for the first time in the BABAR detector at the asymmetric B-factory, PEP-II. It is based on total internal reflection and uses long, rectangular bars made from synthetic fused silica as Cherenkov radiator and light guide. The principles of the DIRC ring imaging Cherenkov technique are explained and results from the prototype program are presented. Its choice for the BABAR detector particle identification system is motivated, followed by a discussion of the quartz radiator properties and the detector design.

An internally reflecting Cherenkov detector (DIRC): properties of the fused silica radiators

The DIRC, a new type of ring-imaging Cherenkov detector that images internally reflected Cherenkov light, is being constructed as the main hadronic particle identification component of the BABAR detector at SLAC. The device makes use of 5 meter long fused silica (colloquially called quartz) bars, which serve both as the Cherenkov radiators and as light pipes for transmitting the light to an array of photo-multiplier tubes. This paper describes a program of research and development aimed at determining whether bars that meet the stringent requirements of the DIRC can be obtained from commercial sources. The results of studies of bulk absorption of fused silica, surface finish, radiation damage and bulk inhomogeneities are discussed.

Design and construction of the front-end electronics data acquisitions for the SLD CRID

The authors describe the front-end electronics for the Cerenkov Ring Imaging Detector (CRID) of the SLD (Stanford Large Detector) at the Stanford Linear Accelerator Center. The design philosophy and implementation are discussed with emphasis on the low-noise hybrid amplifiers, signal processing, and data acquisition electronics. The system receives signals from a highly efficient single-photoelectron detector. These signals are shaped and amplified before being stored in an analog memory and processed by a digitizing system. The data from several analog-to-digital converters are multiplexed and transmitted via fiber optics to the SLD FASTBUS system. The authors highlight the technologies used as well as the space, power-dissipation, and environmental constraints imposed on the system. >

First year operational experience with the Cherenkov detector (DIRC) of BaBar

The DIRC (acronym for Detection of Internally Reflected Cherenkov (light)) is a new type of Cherenkov ring imaging detector based on total internal reflection that is used for the first time in the BaBar detector at the PEP-II ring of SLAC. The Cherenkov radiators are long rectangular bars made of synthetic fused silica, the photon detector is a water tank equipped with an array of 10,752 conventional photomultipliers. The first year operational experience in the BaBar detector is presented using cosmic data and collision data in the energy region of the /spl Upsi/(4S) resonance.

Lorentz angle studies for the SLD endcap Cherenkov Ring Imaging detector

Abstract In the endcaps of the Cherenkov Ring Imaging Detectors for SLD, photoelectrons drift under the influence of crossed electric and magnetic fields. The geometry of the encap design is closely coupled to the Lorentz angle in the chosen drift gas. In this report, we present recent measurements of Lorentz angles and drift velocities in gases suitable for the CRID photon detectors. We compare these measurements to predictions from a theoretical model; good agreement is observed. Based on our results we present a design for detectors operating in a 0.6 T transverse magnetic field.