Environmental influences on gamma ray spectrometry

摘要: Spatially representative sampling of both natural and anthropogenic deposits in the environment is limited by their inherent heterogenic distribution. This problem is compounded when trying to relate ground measurements which are spatially restricted to remote sensing observations not. work examined these widely experienced problems the context measurement (K, U Th) and anthropogenic ( 137Cs ' 34Cs) radioactivity through three techniques soil sampling with laboratory based gamma ray spectrometry, in-situ ray spectrometry, airborne spectrometry. These methods were applied systematically estimate across a tight geometry valley Renfrewshire. Activity estimates from field and airborne spectrometry compared each other results of high resolution soil samples examine relationship between method under variable topographic conditions. These results demonstrated that distribution, post depositional migration, activity had important influences on all techniques, affected ability make comparisons between them. Further detailed studies then conducted influences. The effects of variations composition characteristics environmental ray spectrometry evaluated calculation experimental determination. Corrections standard spectrometric procedures developed to improve systematic precisio:i. investigations also reviewed sampling depth for direct effective comparison spectrometry. The effects small scale errors demonstrated to have a quantifiable influence precision estimation. Lateral variability of distribution radioactivity deposited atmosphere marine sources has been studied in detail at number sites. extent variability depends nature activity, its deposition mode local characteristics. Spatial variability represents an important constraint interpretation derived from examined, comparisons them. Statistically representative plans developed enable spatial comparisons be made sample derived and remotely sensed observations. The vertical measurements has recognised as affecting calibration. use the information scattered spectrum quantify correct source burial was series modelling experiments. A 'Cs source burial forward scattering determined subsequently applied salt marsh environment showed pronounced subsurface maxima. A spectrally calibration correction coefficient shown account for variations across single site. provides potential means for surmounting one principal limitations spectrometry. As result this it possible environmental factors affect laboratory, from aircraft. led development sound methodology comparison between sampling, techniques.