DocumentCode :
836525
Title :
Multichannel Analog to Digital Converter and Readout System for the Time Projection Chamber
Author :
Maier, Michael R. ; Olson, Stanley R. ; Nakamura, Michiyuki ; Goulding, Frederick S.
Author_Institution :
Lawrence Berkeley California University of California Berkeley, California 94720
Volume :
26
Issue :
1
fYear :
1979
Firstpage :
697
Lastpage :
700
Abstract :
The Time Projection Chamber (TPC) project involves the characterization of signals arriving at approximately 20,000 separate detector wires and pad electrodes. The characterization requires measurement of the signal amplitudes in 100 ns time slices over a total time of 20 ¿s (the total chamber drift time). Charge Coupled Devices (CCD\´s) are used to store an image of the 20 ¿s span of signals and the image is "played back" at a low rate (50 ¿s time slices, i.e., a time expansion of 500:1). Digitization of the 20,000 parallel signals at the output of the CCD\´s must therefore be accomplished in 50 ¿s and readout of digital data into the computer system must also be accomplished in this time. Many zeros occur in the data, a fact which reduces the data handling demands on the readout system, but does not reduce the stringent requirements on the digitizer. Therefore, the requirements on the digitizer are highlighted by the need for low cost, low power consumption and by the need to perform 9-bit digitizing in less than 50 ¿s. Furthermore, a double buffering scheme must be used to permit interleaving digitizing and digital readout cycles. We describe our implementation of this concept and some possible applications for other experiments which require many Analog to Digital Converter (ADC) channels.
Keywords :
Analog-digital conversion; Charge-coupled image sensors; Concurrent computing; Costs; Data handling; Detectors; Electrodes; Energy consumption; Time measurement; Wires;
fLanguage :
English
Journal_Title :
Nuclear Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9499
Type :
jour
DOI :
10.1109/TNS.1979.4329710
Filename :
4329710
Link To Document :
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