Download FOREWORD Gamma rays are the most penetrating radiation from

FOREWORD
Gamma rays are the most penetrating radiation from natural and man-made sources, and
gamma ray spectrometry is a powerful tool for the monitoring and assessment of the radiation
environment. Gamma ray surveys are carried out from aircraft, field vehicles, on foot, in
boreholes, on the sea bottom and in laboratories. Ground and airborne gamma ray
measurements cover large areas of the earth’s surface, and many national and regional
radiometric maps have been compiled and published. Standardized maps of terrestrial
radiation and radioelement concentrations can be compared and regionally unified, showing
general regional trends in radionuclide distribution and making the radiological assessment of
the environment possible.
Radiometric surveys and maps are applicable in several fields of science. They retain their
geological and geophysical information for mineral prospecting, geochemical mapping and
structural geology, and enable the comparison of geological features over large regions.
Although the gamma ray method was originally developed for geoscience, it has also been
successfully applied in emergency situations for mapping the contamination from nuclear
fallout and for the location of lost radioactive sources.
The use of modern computer data processing has enabled the introduction of new
interpretation methods and the achievement of greater reliability in solving geological and
environmental problems. The purpose and scope of this report is to introduce the theoretical
background of gamma ray spectrometry in its application to the radiation environment, and to
emphasize and illustrate new procedures in this field based on current knowledge. The report
introduces the principles of radioactivity, contemporary radiation units, and the fundamentals
of gamma ray spectrometry and its application to airborne, ground, car-borne, borehole and
laboratory measurements. Examples of the use of gamma ray spectrometry in environmental
studies and geological mapping illustrate the conditions, requirements and procedures for data
acquisition, processing and reporting using this method.
For many years the International Atomic Energy Agency (IAEA) has been involved in the
treatment of exploration data and their multiple applications related to mineral exploration,
agricultural, and environmental assessment. Recognizing that techniques and methods are
rapidly progressing in this field, the IAEA invited a group of specialists to write a
comprehensive report on radioelement mapping using gamma ray spectrometry. The authors
of this publication are known and recognized specialists from four countries involved in
mapping and data treatment using spectrometry. They all have extensive experience in the
application and use of gamma ray spectrometry for radioelement mapping.
This TECDOC is one of a series of IAEA publications covering all aspects of the uranium
mining industry, from exploration to exploitation, decommissioning, and the application of
techniques in other non-uranium resources areas.
The IAEA officers responsible for this publication were J.-P. Nicolet and G. Erdi-Krausz of
the Division of Nuclear Fuel Cycle and Waste Technology.