T.J. Pavel

Performance of the CRID at SLD

Abstract This paper describes the performance of a large 4π Cherenkov Ring Imaging Detector (CRID) in the SLD experiment at the SLC at SLAC. We compare the most recent SLD results with those obtained during the R&D period, discuss various design features, and highlight some specific lessons derived from three years of operation.

Production of 400 mirrors with high VUV reflectivity for use in the SLD Cherenkov ring imaging detector

Abstract The Stanford Large Detector for experimental particle physics detection at the SLAC Linear Collider contains a Cherenkov ring imaging detector (CRID). The barrel CRID mirrors have been successfully produced and installed. The industrial mirror production process, the quality control of the mirrors produced, and the results of the vacuum ultraviolet (VUV) reflectivity and mirror-shape accuracy are described. An average reflectivity of at least 80% for light at 160 nm and 85% for light in the 180–230 nm wavelength range has been achieved in the production of over 400 mirrors of a typical size of 30 by 30 cm. The surface roughness and optical distortion measurements imply that the light loss due to scattering is a few percent of the incident light and the angular error due to shape distortion is less than 1 mrad.

Monitor and control systems for the SLD Cherenkov ring-imaging detector

To help ensure the stable long-term operation of a Cherenkov Ring Imaging Detector at high efficiency, a comprehensive monitor and control system is being developed. This system will continuously monitor and maintain the correct operating temperatures, and will provide an on-line monitor of the pressures, flows, mixing, and purity of the various fluids. In addition the velocities and trajectories of Cherenkov photoelectrons drifting within the imaging chambers will be measured using a pulsed UV lamp and a fiberoptic light injection system.

The fluid systems for the SLD Cherenkov Ring Imaging Detector

The design and operation of the fluid delivery, monitor, and control systems for the SLD barrel Cherenkov Ring Imaging Detector (CRID) are described. The systems deliver drift gas (C/sub 2/H/sub 6/+TMAE), radiator gas (C/sub 5/F/sub 12/+N/sub 2/), and radiator liquid (C/sub 6/F/sub 14/). Measured critical quantities such as electron lifetime in the drift gas and ultraviolet (UV) transparencies of the radiator fluids, together with the operational experience, are reported. >

Obtaining physics results from the SLD CRID

Abstract We describe the likelihood ratio method used for particle identification in the SLD CRID, which allows the use of the entire momentum range covered by the liquid and gas radiators, including the threshold regions. Its application to two preliminary physics analyses is also described.

Construction and testing of the SLD Cerenkov Ring Imaging Detector

The construction of the Cherenkov Ring Imaging Detector (CRID) for the SLD (Stanford Linear Collider Large Detector) experiment at the SLAC (Stanford Linear Accelerator Center) Linear Collider and the testing of its components is reported. Results are included from testing the drift boxes, liquid radiator trays, and mirrors for the barrel CRID. The development of the support systems essential for the operation of the CRID, namely, gas and liquid recirculation systems and monitoring, are discussed. >

Operational status and performance of the SLD CRID

Abstract The operation and performance of the SLD CRID achieved during the recently completed 1994–1995 run of the SLC will be discussed. Stable operation of liquid (C6F14) and gas (85% C5F12 and 15% N2) radiators with good UV transparency has been achieved. Our expectations for the future SLD physics program will also be briefly discussed.

THE FIRST RESULTS FROM THE CRID DETECTOR AT SLD

We report first results from the initial physics run of the Cherenkov Ring Imaging Detector (CRID) in the SLD experiment at the SLC. We describe the experimental conditions, show liquid and gas rings, report the number of photoelectrons per ring, and comment on resolution.

Initial performance of the SLD Cherenkov ring imaging detector system

All of the major subsystems for the barrel Cerenkov Ring Imaging Detector (CRID) in the SLAC Large Detector (SLD) at Stanford Linear Accelerator Center (SLAC) have now been commissioned. The CRID participated in the SLD engineering run of June-August 1991. In a cosmic ray test at the end of the run, Cerenkov rings were observed for the first time. Initial data for the CRID, including Cerenkov rings, studies of minimum ionizing particles, and data from the fiber optics calibration system are presented. The SLD engineering run and the ensuing dedicated CRID test runs have demonstrated that the system behaves as expected. It has been possible to track particles using ionization in the drift boxes and to reconstruct single electron coordinates very well. The runs have also enabled debugging of this complex system.<<ETX>>

Operational experience with the SLD CRID at the SLC

We highlight some problems encountered and lessons learned in obtaining stable operation of the SLD CRID for the past four years. During the 1994–1995 run of the SLC, we achieved stable operation of liquid (C6F14) and gas (85% C5F1215% N2) radiators with good UV transparency, and we regularly operate the TPCs with excellent drift lifetimes and good single photo-electron detection efficiency.