ADC non-linear error corrections for low-noise temperature measurements in the LISA band

Temperature fluctuations degrade the performance of different subsystems in the LISA mission. For instance, they can exert stray forces on the test masses and thus hamper the required drag-free accuracy. Also, the interferometric system performance depends on the stability of the temperature in the optical elements. Therefore, monitoring the temperature in specific points of the LISA subsystems is required. These measurements will be useful to identify the sources of excess noise caused by temperature fluctuations. The required temperature stability is still to be defined, but a figure around 10μK Hz^-1/2 from 0.1 mHz to 0.1 Hz can be a good rough guess. The temperature measurement subsystem on board the LISA Pathfinder mission exhibits noise levels of 10μK Hz^-1/2 for f >0.1 mHz. For LISA, based on the above hypothesis, the measurement system should overcome limitations related to the analog-to-digital conversion stage which degrades the performance of the measurement when temperature drifts. Investigations on the mitigation of such noise will be here presented.