In situ γ-spectrometry several years after deposition of radiocesium |
| |
Authors: | U Hillmann W Schimmack P Jacob K Bunzl |
| |
Institution: | (1) GSF – Research Center of Environment and Health, Institute for Radiation Protection, D-85758 Neuherberg, Germany, DE |
| |
Abstract: | Several years after the deposition of fallout radiocesium, the maximal activity of this radionuclide will not remain at the
soil surface but be found rather in deeper layers. In order to estimate the total radiocesium contamination of a large area
and the resulting γ-dose rate by in-situ spectrometry, it is necessary to approximate the vertical distribution of this radionuclide by an analytical
function. Observations at ten undisturbed grassland soils in Bavaria, Germany, show that the resulting depth distributions
can be approximated closely by a three-parameter Lorentz function. This function characterises the observed distributions
in all three critical sections, i.e. the surface layer, the distribution around the maximal concentration, and the tail at
greater depth. It is also shown that the observed total activity per unit area of the soil due to 137Cs agrees very well with the corresponding value obtained from the integrated Lorentz function. The two coefficients of the
Lorentz function, which characterise the location (depth) and width of the maximum in the activity distribution, are shown
to be correlated. In part II of this study, it will be shown how the parameters of the Lorentz function can also be obtained
by in-situ γ-ray spectrometry. As a result, it is possible to use in-situ γ-ray spectrometry to obtain the total 137Cs activity per unit area also for sites where the vertical distribution of this radionuclide in the soil is no longer exponential.
Received: 7 March 1996 / Accepted in revised form: 20 June 1996 |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|