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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Evaluation of platinum resistance thermometers

An evaluation procedure for the characterization of industrial platinum resistance thermometers (PRTs) for use in the temperature range -120 to 160 C was investigated. This evaluation procedure consisted of calibration, thermal stability and hysteresis testing of four surface measuring PRTs. Five different calibration schemes were investigated for these sensors. The IPTS-68 formulation produced the most accurate result, yielding average sensor systematic error of 0.02 C and random error of 0.1 C. The sensors were checked for thermal stability by successive and thermal cycling between room temperature, 160 C, and boiling point of nitrogen. All the PRTs suffered from instability and hysteresis. The applicability of the self-heating technique as an in situ method for checking the calibration of PRTs located inside wind tunnels was investigated.

Daryabeigi, Kamran↗
NASA NTRS1990

Compensation for effects of ambient temperature on rare-earth doped fiber optic thermometer

Variations in ambient temperature have a negative effect on the performance of any fiber optic sensing system. A change in ambient temperature may alter the design parameters of fiber optic cables, connectors, sources, detectors, and other fiber optic components and eventually the performance of the entire system. The thermal stability of components is especially important in a system which employs intensity modulated sensors. Several referencing schemes have been developed to account for the variable losses that occur within the system. However, none of these conventional compensating techniques can be used to stabilize the thermal drift of the light source in a system based on the spectral properties of the sensor material. The compensation for changes in ambient temperature becomes especially important in fiber optic thermometers doped with rare earths. Different approaches to solving this problem are searched and analyzed.

Adamovsky, G.↗
NASA NTRS1993

Paramagnetic-Salt Thermometer With Flux Pump And SQUID's

Paramagnetic-salt low-temperature thermometer incorporates improved superconducting magnetic-flux pump, multiple superconducting quantum interference devices as magnetometers, and feedback stabilization of magnetic flux. Requires much smaller initial magnetizing currents and provides improved temperature resolution via suppression of drift in magnetic induction.

Strayer, Donald M.↗
NASA NTRS1993

Concept for a high-resolution thermometer utilizing the temperature dependence of the magnetic penetration depth

A thermometer using the temperature dependence of the magnetic penetration depth in superconductors is described which has the potential for temperature resolution, when using a dc SQUID readout, on the order of 1 pK. One such device has been fabricated and characterized to demonstrate proof of concept. It consists of primary and secondary coils of NbTi wire wound on a copper toroidal core on which a thin layer of In (Tc = 3.4 K) has been deposited. The temperature dependence of the mutual inductance, M(T), or self-inductance, is used to detect changes in temperature. Measurements of M(T) have been made with an ac excitation of the primary for various frequencies and peak magnetic field strengths. Estimates of ultimate temperature resolution are given.

Shirron, P. J.↗
NASA NTRS1940

Corrections on the Thermometer Reading in an Air Stream

A method is described for checking a correction formula, based partly on theoretical considerations, for adiabatic compression and friction in flight tests and determining the value of the constant. It is necessary to apply a threefold correction to each thermometer reading. They are a correction for adiabatic compression, friction and for time lag.

Van Der Maas, H J↗
NASA NTRS1991

Infrared Thermometer

Diatek Corporation, San Diego, CA and the Jet Propulsion Lab developed the Diatek Model 7000 aural thermometer which weighs only eight ounces, and measures temperature in less than two seconds using infrared astronomy technology to measure the amount of infrared energy emitted by the eardrum (the same way temperature of stars and planets is measured). This method avoids contact with mucous membranes, virtually eliminating the possibility of cross infection, and permits temperature measurement of newborn, critically ill, or incapacitated patients. Diatek Corporation was purchased by Welch Allyn Inc. The Diatek Model 7000 is now marketed as SureTemp.

Source record↗
NASA NTRS2001

Electronic Thermometer Readings

NASA Stennis' adaptive predictive algorithm for electronic thermometers uses sample readings during the initial rise in temperature and applies an algorithm that accurately and rapidly predicts the steady state temperature. The final steady state temperature of an object can be calculated based on the second-order logarithm of the temperature signals acquired by the sensor and predetermined variables from the sensor characteristics. These variables are calculated during tests of the sensor. Once the variables are determined, relatively little data acquisition and data processing time by the algorithm is required to provide a near-accurate approximation of the final temperature. This reduces the delay in the steady state response time of a temperature sensor. This advanced algorithm can be implemented in existing software or hardware with an erasable programmable read-only memory (EPROM). The capability for easy integration eliminates the expense of developing a whole new system that offers the benefits provided by NASA Stennis' technology.

Source record↗
NASA NTRS2006

Ingestible Thermometer Pill Aids Athletes in Beating the Heat

Developed by Goddard Space Flight Center and the Johns Hopkins University Applied Physics Laboratory to monitor the core body temperature of astronauts during space flight, the ingestible "thermometer pill" has a silicone-coated exterior, with a microbattery, a quartz crystal temperature sensor, a space-aged telemetry system, and microminiaturized circuitry on the interior.

Source record↗
NASA NTRS1998

Electronic clinical predictive thermometer using logarithm for temperature prediction

A thermometer that rapidly predicts body temperature based on the temperature signals received from a temperature sensing probe when it comes into contact with the body. The logarithms of the differences between the temperature signals in a selected time frame are determined. A line is fit through the logarithms and the slope of the line is used as a system time constant in predicting the final temperature of the body. The time constant in conjunction with predetermined additional constants are used to compute the predicted temperature. Data quality in the time frame is monitored and if unacceptable, a different time frame of temperature signals is selected for use in prediction. The processor switches to a monitor mode if data quality over a limited number of time frames is unacceptable. Determining the start time on which the measurement time frame for prediction is based is performed by summing the second derivatives of temperature signals over time frames. When the sum of second derivatives in a particular time frame exceeds a threshold, the start time is established.

Cambridge, Vivien J.↗
NASA NTRS2009

RuO2 Thermometer for Ultra-Low Temperatures

A small, high-resolution, low-power thermometer has been developed for use in ultra-low temperatures that uses multiple RuO2 chip resistors. The use of commercially available thick-film RuO2 chip resistors for measuring cryogenic temperatures is well known due to their low cost, long-term stability, and large resistance change.

Hait, Thomas↗
NASA NTRS2012

Sonic Thermometer for High-Altitude Balloons

The sonic thermometer is a specialized application of well-known sonic anemometer technology. Adaptations have been made to the circuit, including the addition of supporting sensors, which enable its use in the high-altitude environment and in non-air gas mixtures. There is a need to measure gas temperatures inside and outside of superpressure balloons that are flown at high altitudes. These measurements will allow the performance of the balloon to be modeled more accurately, leading to better flight performance. Small thermistors (solid-state temperature sensors) have been used for this general purpose, and for temperature measurements on radiosondes. A disadvantage to thermistors and other physical (as distinct from sonic) temperature sensors is that they are subject to solar heating errors when they are exposed to the Sun, and this leads to issues with their use in a very high-altitude environment

Bognar, John↗
NASA NTRS2012

Design of High Resolution Soft X-Ray Microcalorimeters Using Magnetic Penetration Thermometers

We have designed high-resolution soft x-ray microcalorimeters using magnetic penetration thermometers (MPTs) in an array of pixels covering a total of 2 square centimeters to have a resolving power of 300 at energies around 300 eV. This performance is desirable for studying the soft x-ray background from the warm hot intergalactic medium. MPT devices have small sensor heat capacity and high responsivities, which makes them excellent detector technology for attempting to attain sub-eV resolution. We are investigating the feasibility of pixels with absorbers that are 625 x 625 square micrometers, up to 1 x 1 square millimeters in area and 0.35 micrometer thick and thinner. Our tests have shown that suspended gold absorbers 0.35 micrometers thick (RRR = 6.7) are feasible to fabricate. We modeled the thermal diffusion from such thin gold over the size of a 625 x 625 square micrometer absorber, and conclude that the effect of the thermalization on the resolution of a 300 eV photon is an additional approximately 0.2 eV FWHM of broadening. We discuss the thermal effects of small absorber attachment sterns on solid substrate, as well as considerations for multiplexed readout. We will present the progress we have made towards building and testing this soft x-ray detector.

Busch. Sarah↗
NASA NTRS2012

Performance of Magnetic Penetration Thermometers for X-Ray Astronomy

The ideal X-ray camera for astrophysics would have more than a million pixels and provide an energy resolution of better than leV FWHM for energies up to 10 keY. We have microfabricated and characterized thin-film magnetic penetration thermometers (MPTs) that show great promise towards meeting these capabilities. MPTs operate in similar fashion to metallic magnetic calorimeters (MMCs), except that a superconducting sensor takes the place of a paramagnetic sensor and it is the temperature dependence of the superconductor's diamagnetic response that provides the temperature sensitivity. We present a description of the design and performance of our prototype thin-film MPTs with MoAu bilayer sensors, which have demonstrated an energy resolution of approx 2 eV FWHM at 1.5 keY and 4.3 eV FWHM at 5.9 keY.

Nagler, P. C.↗
NASA NTRS2012

Superconducting Effects in Optimization of Magnetic Penetration Thermometers for X-ray Microcalorimeters

We have made high resolution x-ray microcalorimeters using superconducting MoAu bilayers and Nb meander coils. The temperature sensor is a Magnetic Penetration Thermometer (MPT). Operation is similar to metallic magnetic calorimeters, but instead of the magnetic susceptibility of a paramagnetic alloy, we use the diamagnetic response of the superconducting MoAu to sense temperature changes in an x-ray absorber. Flux-temperature responsivtty can be large for small sensor heat capacity, with enough dynamic range for applications. We find models of observed flux-temperature curves require several effects to explain flux penetration or expulsion in the microscopic devices. The superconductor is non-local, with large coherence length and weak pinning of flux. At lowest temperatures, behavior is dominated by screening currents that vary as a result of the temperature dependence of the magnetic penetration depth, modified by the effect of the nonuniformity of the applied field occurring on a scale comparable to the coherence length. In the temperature regime where responslvity is greatest, spadal variations in the order parameter become important: both local variations as flux enters/leaves the film and an intermediate state is formed, and globally as changing stability of the electrical circuit creates a Meissner transition and flux is expelled/penetrates to minimize free energy.

Stevenson, Thomas R.↗
NASA NTRS2015

Heat Capacity and Thermal Conductance Measurements of a Superconducting-Normal Mixed State by Detection of Single 3 eV Photons in a Magnetic Penetration Thermometer

We report on measurements of the detected signal pulses in a molybdenum-gold Magnetic Penetration Thermometer (MPT) in response to absorption of one or more 3 eV photons. We designed and used this MPT sensor for x-ray microcalorimetry. In this device, the diamagnetic response of a superconducting MoAu bilayer is used to sense temperature changes in response to absorbed photons, and responsivity is enhanced by a Meissner transition in which the magnetic flux penetrating the sensor changes rapidly to minimize free energy in a mixed superconducting normal state. We have previously reported on use of our MPT to study a thermal phonon energy loss to the substrate when absorbing x-rays. We now describe results of extracting heat capacity C and thermal conductance G values from pulse height and decay time of MPT pulses generated by 3 eV photons. The variation in C and G at temperatures near the Meissner transition temperature (set by an internal magnetic bias field) allow us to probe the behavior in superconducting normal mixed state of the condensation energy and the electron cooling power resulting from quasi-particle recombination and phonon emission. The information gained on electron cooling power is also relevant to the operation of other superconducting detectors, such as Microwave Kinetic Inductance Detectors.

superconductivity↗
NASA NTRS2016

Optical Probe of the Superconducting Normal Mixed State in a Magnetic Penetration Thermometer

Using ultraviolet photon pulses, we have probed the internal behavior of a molybdenum-gold Magnetic Penetration Thermometer (MPT) that we designed for x-ray microcalorimetry. In this low-temperature detector, the diamagnetic response of a superconducting MoAu bilayer is used to sense temperature changes in response to absorbed photons. We have previously described an approximate model that explains the high responsivity of the detector to temperature changes as a consequence of a Meissner transition of the molybdenum-gold film in the magnetic field applied by the superconducting circuit used to bias the detector. We compare measurements of MPT heat capacity and thermal conductance, derived from UV photon pulse data, to our model predictions for the thermodynamic properties of the sensor and for the electron cooling obtained by quasiparticle recombination. Our data on electron cooling power is also relevant to the operation of other superconducting detectors, such as Microwave Kinetic Inductance Detectors.

superconductivity↗