PIRSA Ooldea Doserate Grid Geodetic

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. The terrestrial dose rate grid is derived as a linear combination of the filtered K, U and Th grids. A low pass filter is applied to this grid to generate the filtered terrestrial dose rate grid.This PIRSA Ooldea Doserate Grid Geodetic has a cell size of 0.00083 degrees (approximately 86m) and shows the terrestrial dose rate of the Ooldea-Nullarbor, SA, 2005. The data used to produce this grid was acquired in 2005 by the SA Government, and consisted of 36025 line-kilometres of data at 400m line spacing and 80m terrain clearance.辐射测量法（或称伽马能谱法，gamma-ray spectrometric method）通过探测地球表面附近的伽马射线自然变化，以反映钾（K）、铀（U）与钍（Th）的天然放射性衰变所产生的辐射信号。所采集的数据将通过标准流程进行处理，以确保记录的辐射响应仅源于地下岩石的放射性衰变。经处理得到的数据集可用于解译，以揭示地下地质构造。经处理的数据将由GA地球物理学家开展质量核查，以确保GA发布的最终数据符合使用要求。地表剂量率网格（terrestrial dose rate grid）通过对滤波后的钾、铀、钍网格进行线性组合得到，随后对该网格施加低通滤波器（low-pass filter），以生成滤波后的地表剂量率网格。本次发布的PIRSA欧尔迪亚大地测量剂量率网格，栅格单元尺寸为0.00083度（约86米），展示了2005年南澳州（SA）欧尔迪亚-纳拉伯（Ooldea-Nullarbor）区域的地表剂量率分布。该网格的制作数据由南澳州政府于2005年采集完成，共计36025线公里，测线间距为400米，飞行离地高度为80米。