AN APPRAISAL OF THE NOISE PERFORMANCE OF CONSTANT TEMPERATURE BOLOMETRIC DETECTOR SYSTEMS

The noise and bandwidth behaviour of the constant temperature bolometer detector is analysed with a view to optimising practical systems. It is shown that careful adjustment of the time constants in this type of detector system is essential to avoid serious and unnecessary degradation of the attainable performance. It is concluded that a system with a critically damped response to a heat pulse input is optimal from the point of view of sensitivity and useful signal bandwidth. The use of feedback to enhance artificially the bandwidth of a sensor is considered but it is found that any attempt to compensate for a slow sensor element using this technique degrades the sensitivity seriously. Some general guidelines for the design of sensitive detector systems are suggested.