A scintillation counter for radioactivity prospecting

A transportable scintillation counter instrument, sensitive to gamma rays, has been designed for use in surveying for radioactivity. Use of a single cold cathode valve in the counting-rate meter circuit, which is triggered directly by the counter, and a new form of recording microammeter leads to simplicity and compactness. Recordings are shown of radioactive anomalies detected from the air. The stability and reliability of the instrument have proved satisfactory and have been further tested by use in a geological survey by car for 500 hours over rough road surfaces in tropical climates.