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In the case of normal operations, continuous release of
gaseous radionuclides of trace amount of isotopes of
Ar, Kr and Xe form reactor is found. The purpose of this
study is to examine the applicability of real- time
monitoring of gaseous radionuclides with a high-purity germanium
detector (HPGe). The system, consisted of portable HPGe and
multichannel analyzer (MCA), is designed for the measured both
in sealed chamber and in outdoors surrounded with
gaseous radionuclides. Besides, quantitative,
qualitative, prompt and on-line measurement can be
reached with the portable detectors without air sucking pump and
filter paper.
The research was divided into two major parts as follows : (1)
The HPGe detector was calibrated using artificial gaseous
Ar-41 and Xe- 125,133,135 released to a sealed
chamber. The efficiency in both sealed chamber and
outdoors are formulated from the calibrated volumetric
sealed chamber. (2) We can obtain the effective dose equivalent
of the gaseous radionuclides using dose rate conversion
factors. Detection limit and possible application in field
monitoring are discussed. The results show :
(1) linear relationship between efficiency and
energy in log coordinate be obtained, the detector system is
available for measurement of detection limit (DL) far less
than legal derived air concentration (DAC),
application can be applied to detect the gaseous
radionuclides in nuclear accident and nuclear war. (2) The dose
rate formulated from the counting rate can provide the
rapid information for personal protection and post
accident assessment.
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