A conversion function (
G (
E) function) was determined to obtain an exposure rate directly from a r-ray spectrum measured by an
in-situ Ge(Li) spectrometer. In order to verify the utility of the
G (
E) function method, three kinds of detector, namely, a port-able Ge (Li) detector, a Nal (Tl) detector and an ionization chamber, were used to measure exposure rate due to environmental γ-rays at the same place, and the measured values of exposure rate were compared with each other. Two exposure rate values were obtained from a r-ray spectrum measured by the Ge (Li) detector, using two different methods, namely, the
G (
E) function method and the HASL method. The average of ex-posure rates obtained by four different methods was 4.15 pR/h, and the deviation was 15% of the average.
By applying both the
G (
E) function method and the HASL method to an environ-mental r-ray spectrum, a total exposure rate can be determined directly without informa-tion on the distribution of the radionuclides in soil, and individual exposure rates due to
40K,
238U and
232Th series and
137Cs of the known distribution in soil can be also determined.
抄録全体を表示