| Summary: | 碩士 === 國立清華大學 === 原子科學研究所 === 81 === The purpose of this study is to examine the applicabi- lity of
real-time monitoring of gaseous radionuclide with a high-
purity germanium (HPGe) detector. In the case of normal
operations, continuous release of gaseous radio- nuclides of
tracer amount of isotopes of Ar,Kr and Xe from reactor is
found. The system, consisted of portable HPGe and
multichannel analyzer (MCA), is designed for the
measurement both in sealed chamber and in outdoors sur-
rounded with gaseous radionuclide. Besides, quantitative,
qualitative, prompt and on-line measurement can be reached with
the movable detectors without air sucking pump and filter
paper. The research was divided into two major parts as
follows : (1) The HPGe detector was calibrated by using of
artificial gaseous Ar-41,Kr-85m and Xe-125,133,135 releas- ed
to a sealed chamber. Minimum detectable concentration and
possible application field monitoring are discussed. (2)
Three various types of HPGe detectors were calibrated , the
relationship between detectors' efficiency and the crystal
volume was observed. The results show : (1)linear relationship
between eff- iciency and energy in log coordinate can be
obtained. The detector system is available for the
measurement of minimum detectable concentration (MDC) far less
than legal maximum permissible concentration (MPC),
application to detect the gaseous radionuclide of nuclear
disaster and nuclear war.(2) There exists a linear relationship
between crystal volume and relative efficiency so that the
inter- relation between efficiencys with various detectors can
be developed in emergenecy.
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