Low noise temperature control: Application to an active cavity radiometer

Abstract

We have designed low noise temperature sensing and control units with the objective of using them for the fabrication of far infrared active cavity radiometers.The sensing unit, first characterized at 300 K using industrial platinium resistance thermometers, has a noise level of ∼ 25 − 30 µK ef f for a 3 hours measuring time and in a 1 Hz bandwidth. Using YBCO superconducting thermometers, the noise level goes down to 2.5 µK ef f , which is strongly limited by excess 1/f noise in the YBCO film at the superconducting transition. The sample holder used in the 90 K experiments is built with an auxiliary heating resistor, which enables an easy and accurate identification of the electrothermal model, even in the closed loop operation. Based on a design previously published by NIST, we estimate from these experimental results that the overall noise limitations of radiometers could be lowered by one order of magnitude.

Design and verification of an effective state‐of‐charge estimator for thermal energy storage

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“…In the third simulation scenario, a fully equipped tank with a temperature sensor per layer is considered, but the sensor failure is assessed. During the simulation, the availability of sensed signals T 26) to (29). Simulation results are provided in Figures 16-19.…”

Thermal diagnostics front-end electronics for LISA Pathfinder

“…18 The polarity of the bridge excitation source is reversed and a measurement is taken for each polarity. Hence, each temperature sample is the average difference between two consecutive measurements.…”

“…Another design can be found for an active cavity radiometer where platinum resistance thermometers ͑PRTD͒ and yttrium barium cuprate ͑YBCO͒ superconducting thermometers have been tested at room temperature exhibiting sensitivities up to 10 −5 K Hz −1/2 at 0.1 Hz. 18 This article describes the temperature measurement chain designed to fulfill the requirements of Eq. ͑4͒ and the tests carried out to ascertain whether or not they are actually met.…”

Optical and Electrical Characterizations of Uncooled Bolometers Based on LSMO Thin Films

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