Childara - Th equivalent concentration grid (AWAGS, nasvd)

The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data collected are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.This radiometric thorium grid has a cell size of 0.0004 degrees (approximately 41m) and shows thorium element concentration of the Childara Airborne Magnetic Radiometric and DEM Survey, SA, 2017 in units of parts per million (or ppm). The data used to produce this grid was acquired in 2017 by the SA Government, and consisted of 135047 line-kilometres of data at 200m line spacing and 60m terrain clearance. To constrain long wavelengths in the grid, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey grid.

放射性测量法（radiometric method），又称伽马能谱法（gamma-ray spectrometric method），可通过检测地球表面附近的伽马射线自然变化，表征由钾（K）、铀（U）与钍（Th）的自然放射性衰变产生的辐射信号。所采集的数据将通过标准化流程进行处理，以确保记录到的响应仅源于地下岩石的放射性衰变。经处理后得到的数据集可通过解译，揭示地下地质构造特征。经处理后的数据将由GA地球物理学家开展质量核验，以确保GA对外发布的最终数据符合使用需求。
本钍元素放射性测量网格的像元尺寸为0.0004度（约合41米），展示的是2017年南澳大利亚州（SA）奇达拉（Childara）航空磁法-放射性测量与数字高程模型（Digital Elevation Model, DEM）调查中的钍元素浓度，单位为百万分率（ppm）。本网格所用数据由南澳大利亚州政府于2017年采集，总测线长度达135047测线千米，测线间距为200米，飞行离地高度为60米。为约束网格中的长波长信号，本次调查采用独立数据集——澳大利亚全域航空地球物理调查（Australia-wide Airborne Geophysical Survey, AWAGS）的航空磁法数据，来管控本次测量网格的基准水平。