Initial Plan for a Precision Temperature Sensor

Precision microwave radiometry requires accurate internal calibration sources. A microwave terminator is one such internal source, and, under the assumption of a high quality match, produces a noise power directly proportional to the physical temperature of the terminator. Precise measurement of this temperature is required in order to provide a quality calibration standard. It is desirable for this temperature to be monitored and recorded frequently (perhaps every second or few seconds) during operation of the system, so an interface to computer control and recording is of importance. Current research in L-band microwave radiometry is working toward brightness temperature measurement accuracies on the order of 0.1 K, so that even more precise measurements of internal physical temperatures are required. Although a 0.1 K brightness accuracy is not necessarily required for the IIP radiometer, achieving a high accuracy terminator temperature measurement remains a worthwhile goal, and is feasible with moderate effort. This document provides a review of candidate temperature sensors, and a specific suggested plan for the IIP radiometer. The detailed plan will be described in a future document.