A Calibration Range in South-Eastern Australia for Airborne Gamma-Ray Spectrometers

A calibration range is an easily navigable strip of land that is used to measure the response of an airborne spectrometer system to changes in aircraft altitude (height attenuation coefficients), and to sources of known concentration (sensitivity coefficients). This paper describes the selection and assessment of an airborne gamma-ray spectrometric calibration range for southeastern Australia. We review the selection criteria for establishing a calibration range, and present the calibration results for a new calibration range near Albury, New South Wales. Background measurements are made over Lake Hume, which is about 27 km away. The calibration range was flown during a period of particularly low atmospheric radon background and this reduced the errors associated with background estimation and removal. The calibration range has most of the desirable features expected of an ideal calibration range. We are hopeful that with the continued cooperation of the local landowners, this range will become a permanent calibration facility for southeastern Australia.