Thermocouple Temperatures in a Diffusion Cloud Chamber

Abstract

The radial and vertical thermocouple temperatures in a cylindrical diffusion cloud chamber have been measured during operation, using copper‐constantan thermocouples supported by a light Bakelite framework. Readings were taken at regular time intervals, beginning with the addition of the solid CO₂, through thermal ``equilibrium,'' and until the chamber had ceased to operate upon the depletion of the refrigerant. The vertical thermocouple temperature gradient in the sensitive volume (the lower one‐third of the chamber) was found to be approximately 13°C/cm. The addition of heat to the top of the chamber had negligible effect on the vertical gradient in the bottom third of the chamber and hence changed the depth of the sensitive volume only slightly. There appeared to be no appreciable horizontal gradient.