TNAG-1508-FCO40-2066-Guangdong-nuclear-power-station-project-at-Daya-Bay-safety-c-1987 — Page 55

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Ionic radiation metrology mainly concentrates on the

following major areas of studies: first, to measure the amount

of the radioactive substance itself; that is, to measure the

converting amount of a certain radioactive nuclide in a unit of

time--in other words, the radioactivity; and second, to measure

the amount of mutual effect between the ionic radiation and the

substance being irradiated, that is, the energy given to the

substance by the ionic radiation when it pierces through the

substance, which is usually called the ionic radiation dose.

The measuring of the radioactivity of the nuclide

constitutes the foundation for the study of radiation dose and

neutronic metrology. The unit of radioactivity is becquerel

-1

1 Bq

1s 1, that is, one becquerel

1

for occurring one decay in a second.

(Bq).

equals to the radioactivity

As standard for the measurement of radioactivity, the

following are usually used: 4 shaft ionization chamber; Ge (Li)

Y-ray spectrometer, and the large-size NaI (T1) shaft detector.

Among them, 4 ionization chamber is the best modern method used

in the relative measuring of the Y-ray radioactivity of the

nuclide. It is recommended for. its simple operation; stability

of performance and high precision.

The most important and most often used radiation doses in

radiation dosimetry are the irradiation dose and absorption dose.

P. 2

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