A versatile cryogenic temperature controller

We present the design and implementation of a versatile cryogenic temperature controller based on a microcontroller, characterized by high-accuracy and stability. It has been used to perform automated measurements on electron devices operating at very low temperatures. Noise measurements on such devices are particularly sensitive, because random fluctuations of temperature can result in electrical noise superimposed to the quantity being measured. The system described in this contribution can operate as a stand-alone unit or can be remotely controlled via an RS232 interface. High accuracy and stability (±50 mK in the 10-300 K range), low noise, and an overall low cost are the main results that have been achieved.