Thermal diagnostics front-end electronics for LISA Pathfinder

Precision temperature measurements are required in the LTP, the LISA technology package, for various diagnostics objectives. In this article, we describe in detail the front-end electronics design and the associated temperature sensors to achieve the LTP requirements: noise equivalent temperature of 10μKHz−1∕2 in the frequency range from 1to30mHz at room temperature. We designed an ac Wheatstone bridge and a subsequent digital demodulation to minimize 1∕f noise. We show experimental results where the required sensitivity in the measurement bandwidth is fulfilled.