Hans Geiger, having previously worked with Rutherford in Manchester (first detector, 1908), develops together with Walther Müller in 1913 in Berlin the improved, self-contained design known as the Geiger-Müller counter. The instrument detects individual ionizing particles through an electrical pulse in a gas tube. It has been the standard instrument for detecting nuclear radiation ever since, indispensable in medicine, nuclear physics, and radiological safety.