Development report: a RADIAC system for measuring aqueous tritium concentration by the liquid scintillation method
This report describes the design, assembly, and testing of a room temperature bench-scale liquid scintillation system for aqueous tritium measurement. With this system urine or water samples with tritium concentrations of 1 to 5 microCuries per liter can be measured within 20% uncertainty in a typical counting time of 40 seconds to 3 minutes, depending on the background count rate, activity level, and degree of quench. Concentrations above 5 ..mu..Ci/L can be measured with 10% uncertainty in a typical counting time of less than 3 minutes. In water samples, tritium concentrations as low as 0.1 ..mu..Ci/L can be measured within 20% uncertainty in a typical counting time of 30 minutes, and within 30% uncertainty in less than 10 minutes. These operating parameters may be modified if necessary. For instance, changing the minimum measurable activity from 1 ..mu..Ci/L to as little as 0.1 ..mu..Ci/L can be accomplished by a simple change in the operating program. The microprocessor incorporated into this system collects, processes, and transmits data and also interacts with the operator, which minimizes the work load and thereby reduces the chance of operator-induced error. Very little training is required: the operator simply follows basic instructions on the display. A novel photomultipiler tube balance circuit was developed especially for use with this system. It maximizes counting efficiency and eliminates the need for stocking matched pairs of photomultiplier tubes. The design of the signal processing system is based on the use of a fast coincidence gate. This eliminates the need for refrigerating the scintillator or storing it in the dark. The design of the system also allows the degree of quench for a particular sample to be determined without the use of a radioactive gamma source. Gamma sources are used to determine quench in many commercial liquid scintillation counters.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 5708502
- Report Number(s):
- DOE/NBM-4001927; ON: DE84001927
- Country of Publication:
- United States
- Language:
- English
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Development report: RADIAC systems for measuring aqueous tritium concentration by the liquid scintillation method (Engineering Materials)
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
AMPLIFICATION
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY FLUIDS
CALIBRATION
COMPUTERS
DATA PROCESSING
DESIGN
ELECTRONIC CIRCUITS
GAIN
LIQUID SCINTILLATION DETECTORS
MATERIALS
MEASURING INSTRUMENTS
METERS
MICROELECTRONIC CIRCUITS
MICROPROCESSORS
PHOTOMULTIPLIERS
PHOTOTUBES
PROCESSING
RADIATION DETECTORS
SCINTILLATION COUNTERS
TRITIUM METERS
URINE
WASTES