The extended surface forces apparatus.: II.: Precision temperature control

We describe the design and performance of a low-cost, bidirectional temperature control system with very high stability and low thermal gradients in a working range from -10 to 70 degreesC. System elements such as thermal insulation, thermal pumps, and feedback control as well as safety features are discussed. The performance of the entire system under realistic experimental conditions is documented. Precise temperature control has led to significantly improved instrumental stability. An extension of the instrumental window towards slower measurements has been made possible. This temperature-control system is presented in the framework of the extended surface forces apparatus but is also applicable to other scientific instruments that require subnanometer positioning stability over extended periods of time. (C) 2001 American Institute of Physics.