G. Oxoby

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 (

Monitoring of the Stanford Linac Microbunches' Position

A new hardware has been developed to measure the trajectory of microbunches along the Stanford Linac. To be suitable for the operation of the SLAC Single Pass Collider, the bunches absolute position must be kept within ±100 microns of the accelerator center, and the acquisition of this measurement must be made along the machine in a snapshot fashion. Typically, the position of three bunches will be monitored during subsequent shots; we expect a minimum charge of 109 particles per bunch and a time spacing between bunches of 50 nanoseconds. The mechanics of the position detectors is described as well as the general system organization and the calibration of various components.

Development of a low noise preamplifier for the detection and position determination of single electrons in a Cerenkov ring imaging detector by charge division

A preamplifier using a low-noise dual-gate MOSFET front end has been designed, built, and tested. It performs well, having a noise level of about 500 electrons RMS at a shaping time of 65 ns. It is linear over its entire range to better than 1%. It has been used to detect single photoelectrons in a Cerenkov ring imaging detector. A single channel contains preamp, RC-CR shaper, gain adjustment, driver, and calibration circuitry. The circuit is described in detail, and results of noise and linearity measurements are presented. >

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.

Progress report on the SLD cerenkov ring imaging detector

We describe test beam results from a prototype cerenkov Ring Imaging Detector (CRID) for the SLD experiment at the SLAC Linear Collider (SLC). The system includes both liquid and gas radiators, a long drift box containing gaseous TMAE and a proportional wire chamber with charge division readout. Measurements of the multiplicity and detection resolution of cerenkov photons, from both radiators are presented. Various design aspects of a new engineering prototype, currently under construction, are discussed and recent R&D results relevant to this effort are reported.

Experience Using the 168/E Microprocessor for off-Line Data Analysis

The 168/E is a SLAC developed microprocessor which emulates the IBM 360/370 computers with an execution speed of about one half of a IBM 370/168. These processors are used in parallel for the track finding and geometry programs of the LASS spectrometer. The system is controlled by a PDP-11 minicomputer via a three port interface which we call the Bermuda Triangle. The tape handling and downloading is controlled by one of SLACs IBM computers via a SLAC built interface between the PDP-11 and an IBM channel. Initially, there will be a system of 6 168/Es which should be able to give six times the production capacity than can be attained by running production jobs on the SLAC Triplex system. The cost of the system, including the channel interface, is

A liquid hydrogen target for the precision measurement of the weak mixing angle in Møller scattering at SLAC

120,000 and yet it yields the equivalent computer power of 3 IBM 370/168s. Hence, this system is an extremely cost-effective method for off-line data analysis.

Cherenkov Ring Imaging Detector front-end electronics

A 150 cm long liquid hydrogen target has been built for the SLAC End Station A E158 experiment. The target loop volume is 55 liters, and the maximum target heat load deposited by the electron beam is {approx} 700 W. The liquid hydrogen density fluctuation with full beam current (120 Hz repetition rate, 6 x 10{sup 11} electrons/spill) on target is well below 10{sup -4} level, which fulfills the requirement for a precision measurement of the weak mixing angle in the polarized electron-electron scattering process.

Progress report on the SLD Cerenkov Ring Imaging Detector system

The front-end electronics of the Cerenkov Ring Imaging Detector (CRID) used in the Stanford Large Detector (SLD) spectrometer at the Stanford Linear Accelerator Center (SLAC) Linear Collider is described. The Plessey process provides a straightforward and low-cost path toward system miniaturization. System tests show good noise performance, calibration precision, system linearity, and signal shape uniformity over the full dynamic range. >