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Title: Fast charge digitizer and digital data acquisition system for measuring time varying radiation fields

Abstract

A radiation measuring instrument including a fast charge digitizer and a digital data acquisition system has been developed. The fast charge digitizer includes a charge integrator connected to a conventional ionization chamber which generates an output current in proportion to ionizing radiation exposure rate. The charge integrator has an output connected to a comparator which is switched from a high state to a low state when the output of the integrator goes above the comparator threshold. The comparator output is connected to a bistable multivibrator consisting of two non-retriggerable one shot multivibrators connected in a feedback configuration. As long as the comparator output is in the low state, the bistable multivibrator generates a train of pluses which are fed back through an analog switch and a high megohm resistance to the input of the integrator. This feedback is negative and has the effect of removing the charge from the integrating capacitor, thus causing the integrator output eventually to drop below the comparator threshold. When this occurs the comparator output returns to the high state and the bistable multivibrator ceases to generate output pulses. An output terminal is connected between the bistable multivibrator and the analog switch and feeds a trainmore » of pulses proportional to the amount of charge generated by the multivibrator output voltage and the high megohm resistance to a counter connected to a random access memory device. The output pulses are counted for a predetermined time and then stored in one of the data locations of the random access memory device. The counter is then reset and a further predetermined sample period is counted. This continues until all of the locations in the random access memory device are filled and then the data is read from the random access memory device.« less

Inventors:
; ;
Publication Date:
OSTI Identifier:
7339347
Patent Number(s):
US 3959653
Application Number:
TRN: 76-021252
Assignee:
Secretary of the Department of Health, Education and Welfare
Resource Type:
Patent
Resource Relation:
Patent File Date: Filed date 14 Apr 1975
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; EXPOSURE RATEMETERS; DESIGN; IONIZATION CHAMBERS; COUNTING CIRCUITS; DATA ACQUISITION SYSTEMS; DIGITAL CIRCUITS; DIGITIZERS; FEEDBACK; MEMORY DEVICES; ELECTRONIC CIRCUITS; MEASURING INSTRUMENTS; RADIATION DETECTORS; RADIATION MONITORS; 440101* - Radiation Instrumentation- General Detectors or Monitors & Radiometric Instruments

Citation Formats

Lee, T R, Schneider, R H, and Wyatt, J L. Fast charge digitizer and digital data acquisition system for measuring time varying radiation fields. United States: N. p., 1976. Web.
Lee, T R, Schneider, R H, & Wyatt, J L. Fast charge digitizer and digital data acquisition system for measuring time varying radiation fields. United States.
Lee, T R, Schneider, R H, and Wyatt, J L. 1976. "Fast charge digitizer and digital data acquisition system for measuring time varying radiation fields". United States.
@article{osti_7339347,
title = {Fast charge digitizer and digital data acquisition system for measuring time varying radiation fields},
author = {Lee, T R and Schneider, R H and Wyatt, J L},
abstractNote = {A radiation measuring instrument including a fast charge digitizer and a digital data acquisition system has been developed. The fast charge digitizer includes a charge integrator connected to a conventional ionization chamber which generates an output current in proportion to ionizing radiation exposure rate. The charge integrator has an output connected to a comparator which is switched from a high state to a low state when the output of the integrator goes above the comparator threshold. The comparator output is connected to a bistable multivibrator consisting of two non-retriggerable one shot multivibrators connected in a feedback configuration. As long as the comparator output is in the low state, the bistable multivibrator generates a train of pluses which are fed back through an analog switch and a high megohm resistance to the input of the integrator. This feedback is negative and has the effect of removing the charge from the integrating capacitor, thus causing the integrator output eventually to drop below the comparator threshold. When this occurs the comparator output returns to the high state and the bistable multivibrator ceases to generate output pulses. An output terminal is connected between the bistable multivibrator and the analog switch and feeds a train of pulses proportional to the amount of charge generated by the multivibrator output voltage and the high megohm resistance to a counter connected to a random access memory device. The output pulses are counted for a predetermined time and then stored in one of the data locations of the random access memory device. The counter is then reset and a further predetermined sample period is counted. This continues until all of the locations in the random access memory device are filled and then the data is read from the random access memory device.},
doi = {},
url = {https://www.osti.gov/biblio/7339347}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue May 25 00:00:00 EDT 1976},
month = {Tue May 25 00:00:00 EDT 1976}
}