GSNSW Exploration NSW Area S Braidwood thorium 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, uranium and thorium. The data are collected on airborne geophysical surveys conducted by Commonwealth, State & NT Governments and the private sector.

放射性测量法（radiometric method），亦称伽马射线能谱法（gamma-ray spectrometric method），通过探测地球表层附近的伽马射线自然变化，以反映钾、铀、钍天然放射性衰变产生的伽马射线特征。该数据集由联邦、各州及北领地政府与私营机构开展的航空地球物理调查采集所得。