Search NASA⌕ Search

SEARCH · Search NASA

Results for “TES”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Progress on Background-Limited Membrane-Isolated TES Bolometers for Far-IR/Submillimeter Spectroscopy

To determine the lowest attainable phonon noise equivalent power (NEP) for membrane-isolation bolometers, we fabricated and measured the thermal conductance of suspended Si3N4 beams with different geometries via a noise thermometry technique. We measured beam cross-sectional areas ranging from 0.35 x 0.5 (micro)m(sup 2) to 135 x 1.0 (micro)m(sup 2) and beam lengths ranging from (micro)m to 8300 (micro)m. The measurements directly imply that membrane-isolation bolometers are capable of reaching a phonon noise equivalent power (NEP) of 4 x 10(sup -20)W/Hz(sup 1)/O . This NEP adequate for the Background-Limited Infrared-Submillimeter Spectrograph (BLISS) proposed for the Japanese SPICA observatory, and adequate for NASA's SAFIR observatory, a 10-meter, 4 K telescope to be deployed at L2. Further, we measured the heat capacity of a suspended Si 3N 4 membrane and show how this result implies that one can make membrane-isolation bolometers with a response time which is fast enough for BLISS.

submillimeter spectrometer↗
NASA NTRS2007

Modelling of TES X-ray Microcalorimeters with a Novel Absorber Design

Our development of a novel x-ray absorber design that has enabled the incorporation of high-conductivity electroplated gold into our absorbers has yielded devices that not only have achieved breakthrough performance at 6 keV, but also are extraordinarily well modelled. We have determined device parameters that reproduce complex impedance curves and noise spectra throughout transition. Observed pulse heights, decay time and baseline energy resolution were in good agreement with simulated results using the same parameters. In the presentation, we will show these results in detail and we will also show highlights of the characterization of our gold/bismuth-absorber devices. We will discuss possible improvement of our current devices and expected performance of future devices using the modelling results.

Iyomoto, Naoko↗
NASA NTRS2011

Global Multi-Year O3-CO Correlation Patterns from Models and TES Satellite Observations

The correlation between measured tropospheric ozone (O3) and carbon monoxide (CO) has been used extensively in tropospheric chemistry studies to explore the photochemical characteristics of different regions and to evaluate the ability of models to capture these characteristics. Here, we present the first study that uses multi-year, global, vertically resolved, simultaneous and collocated O3 and CO satellite (Tropospheric Emission Spectrometer) measurements, to determine this correlation in the middle/lower free troposphere for two different seasons, and to evaluate two chemistry-climate models. We find results that are fairly robust across different years, altitudes and timescales considered, which indicates that the correlation maps presented here could be used in future model evaluations. The highest positive correlations (around 0.8) are found in the northern Pacific during summer, which is a common feature in the observations and the G-PUCCINI model. We make quantitative comparisons between the models using a single-figure metric (C), which we define as the correlation coefficient between the modeled and the observed O3-CO correlations for different regions of the globe. On a global scale, the G-PUCCINI model shows a good performance in the summer (C =0.71) and a satisfactory performance in the winter (C = 0.52). It captures midlatitude features very well, especially in the summer, whereas the performance in regions like South America or Central Africa is weaker. The UKCA model (C = 0.46/0.15 for July-August/December-January on a global scale) performs better in certain regions, such as the tropics in winter, and it captures some of the broad characteristics of summer extratropical correlations, but it systematically underestimates the O3-CO correlations over much of the globe. It is noteworthy that the correlations look very different in the two models, even though the ozone distributions are similar. This demonstrates that this technique provides a powerful global constraint for understanding modeled tropospheric chemical processes. We investigated the sources of the correlations by performing a series of sensitivity experiments. In these, the sign of the correlation is, in most cases, insensitive to removing different individual emissions, but its magnitude changes downwind of emission regions when applying such perturbations. Interestingly, we find that the O3-CO correlation does not solely reflect the strength of O3 photochemical production, as often assumed by earlier studies, but is more complicated and may reflect a mixture of different processes such as transport.

Voulgarakis, A.↗
NASA NTRS2016

Performance of Backshort-Under-Grid Kilopixel TES Arrays for HAWC+

We present results from laboratory detector characterizations of the first kilopixel BUG arrays for the High- resolution Wideband Camera Plus (HAWC+) which is the imaging far-infrared polarimeter camera for the Stratospheric Observatory for Infrared Astronomy (SOFIA). Our tests demonstrate that the array performance is consistent with the predicted properties. Here, we highlight results obtained for the thermal conductivity, noise performance, detector speed, and first optical results demonstrating the pixel yield of the arrays.

Staguhn, J. G.↗
NASA NTRS2019

Extended Line Spread Function of TES Microcalorimeters with Au/Bi Absorbers

Microcalorimeters have the potential to provide line shapes well-described by a single Gaussian broadening term of few-eV width. This attribute makes the detectors especially well suited for x-ray astrophysics observations; however, low-level non-Gaussian broadening terms are expected and must be characterized. These terms depend on the composition of the x-ray absorber, the detailed x-ray absorption physics, the device thermalization processes, and the incident x-ray energy. Here we present the first measurements targeted at understanding the extended line-spread function (LSF) of x-ray microcalorimeter pixels under development for the X-ray Integral Field Unit (XIFU) on the Athena X-ray Observatory. These pixels are comprised of Mo/Au transition-edge sensors (TESs) with overhanging electroplated Au/Bi absorbers. We measured the line shapes using monochromatic x-ray sources with < 1 eV width at several x-ray energies (0.85, 0.93, 1.25, 1.5, 5.4, and 8.0 keV) across the instrument bandpass (0.3-12 keV) and modeled the line profiles. These results are compared to the extended LSF of the Hitomi microcalorimeter pixels that used HgTe absorbers.

Superconducting devices↗