On the Automatic Registration ofα-Particles,β-particles andγ-Ray and X-Ray Pulses

Synopsis. A device is described which makes it possible for $\alpha$-particles, $\beta$-particles and $\gamma$-ray and X-rays pulses to make records automatically on chronograph paper, which records can be conveniently and accurately studied at leisure. Historically, the method developed from Rutherford's method of counting $\alpha$-particles and the last previously described development was by the writer in which he used a telephone receiver whose diaphragm was actuated by the current to a needle electrode, after amplification by means of a 3-electrode vacuum tube. In the present method the amplified current actuates a sensitive relay which in turn operates the chronograph pen by means of a local circuit. The accuracy of the records was checked up for the $\alpha$-particles by the scintillation method of counting and for the $\beta$-particles by determining the charge carried by the $\beta$-particles. Records of $\gamma$-rays and X-rays are similar to those of the $\alpha$- and $\beta$-particles and some arguments are given supporting the idea that the records represent individual pulses or short trains of pulses. A record of $\beta$-particles taken over a 7-hour period was studied and conclusion deduced that the variations in the number of $\beta$-particles emitted in a given time interval follow the probability law.