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  • 1
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    Determination of Lateral Diffusivity in Single Pixel X-ray Absorbers with Implications for Position Dependent Excess Broadening (2005)
    In:  Other Sources
    Details
    Publication Date: 2019-07-18
    Description: An ideal microcalorimeter is characterized by a constant energy resolution across the sensor's dynamic range. Any dependence of pulse shape on the position within the absorber where an event occurs leads to a degradation in resolution that is linear with event s energy (excess broadening). In this paper we present a numerical simulation that was developed to model the variation in pulse shape with position based on the thermal conductivity within the absorber and between the absorber, sensor, and heat bath, for arbitrarily shaped absorbers and sensors. All the parameters required for the simulation can be measured from actual devices. We describe how the thermal conductivity of the absorber material is determined by comparing the results of this model with data taken from a position sensitive detector in which any position dependent effect is purposely emphasized by making a long, narrow absorber that is read out by sensors on both end. Finally, we present the implications for excess broadening given the measured parameters of our X-ray microcalorimeters.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: LTD 11; Jul 31, 2005 - Aug 05, 2005; Tokyo; Japan
    Format: text
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  • 2
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    Thermodynamic Performance of the 3-Stage ADR for the Astro-H Soft X-Ray Spectrometer Instrument (2015)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Soft X-ray Spectrometer (SXS) instrument[1] on Astro-H[2] will use a 3-stage ADR[3] to cool the microcalorimeter array to 50 mK. In the primary operating mode, two stages of the ADR cool the detectors using superfluid helium at 1.20 K as the heat sink[4]. In the secondary mode, which is activated when the liquid helium is depleted, the ADR uses a 4.5 K Joule-Thomson cooler as its heat sink. In this mode, all three stages operate together to continuously cool the (empty) helium tank and singleshot cool the detectors. The flight instrument - dewar, ADR, detectors and electronics - were integrated in 2014 and have since undergone extensive performance testing. This paper presents a thermodynamic analysis of the ADR's operation, including cooling capacity, heat rejection to the heat sinks, and various measures of efficiency.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: GSFC-E-DAA-TN27442 , Cryogenics (ISSN 0011-2275); 74; 24-30
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  • 3
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    Flow Property Measurement Using Laser-Induced Fluorescence in the NASA Ames Interaction Heating Facility (2011)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The spectroscopic diagnostic technique of two photon absorption laser-induced fluorescence (TALIF) of atomic species has been applied to single-point measurements of velocity and static temperature in the NASA Ames Interaction Heating Facility (IHF) arc jet. Excitation spectra of atomic oxygen and nitrogen were recorded while scanning a tunable dye laser over the absorption feature. Thirty excitation spectra were acquired during 8 arc jet runs at two facility operating conditions; the number of scans per run varied between 2 and 6. Curve fits to the spectra were analyzed to recover their Doppler shifts and widths, from which the flow velocities and static temperatures, respectively, were determined. An increase in the number of independent flow property pairs from each as-measured scan was obtained by extracting multiple lower-resolution scans. The larger population sample size enabled the mean property values and their uncertainties for each run to be characterized with greater confidence. The average plus or minus 2 sigma uncertainties in the mean velocities and temperatures for all 8 runs were plus or minus 1.4% and plus or minus 11%, respectively.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: ARC-E-DAA-TN2704 , 49th Aerospace Sciences Meeting and Exhibit; Jan 04, 2011 - Jan 07, 2011; Orlando, FL; United States
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  • 4
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    Predicted Ice Shape Formations on a Boundary Layer Ingesting Engine Inlet (2019)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Computational ice shapes were generated on the boundary layer ingesting engine nacelle of the D8 Double Bubble aircraft. The computations were generated using LEWICE3D, a well-known CFD icing post processor. A 50-bin global drop diameter discretization was used to capture the collection efficiency due to the direct impingement of water onto the engine nacelle. These discrete results were superposed in a weighted fashion to generate six drop size distributions that span the Appendix C and O regimes. Due to the presence of upstream geometries, i.e. the fuselage nose, the trajectories of the water drops are highly complex. Since the ice shapes are significantly correlated with the collection efficiency, the upstream fuselage nose has a significant impact on the ice accretion on the engine nacelle. These complex trajectories are caused by the ballistic nature of the particles and are thus exacerbated as particle size increases. Shadowzones are generated on the engine nacelle, and due to the curvature of the nose of the aircraft the shadowzone boundary moves from lower inboard to upper outboard as particle size increases. The largest particle impinging one the engine nacelle from the 50-bin discretization was the 47 um drop diameter. As a result, the MVD greater than 40 um Appendix O conditions were characterized by extremely low collection efficiency on the engine nacelle for these direct impingement simulations.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: GRC-E-DAA-TN66779 , International Conference on Icing of Aircraft, Engines, and Structures; Jun 17, 2019 - Jun 21, 2019; Minneapolis, MN; United States
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  • 5
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    Microbiological Validation of the IVGEN System (2013)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: The principal purpose of this report is to describe a validation process that can be performed in part on the ground prior to launch, and in space for the IVGEN system. The general approach taken is derived from standard pharmaceutical industry validation schemes modified to fit the special requirements of in-space usage.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: GRC-E-DAA-TN7775 , NASA/CR-2013-216500 , E-18638
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  • 6
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    Consolidated Laser-Induced Fluorescence Diagnostic Systems for the NASA Ames Arc Jet Facilities (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The spectroscopic diagnostic technique of two photon absorption laser-induced fluorescence (TALIF) of atomic species for non-intrusive arc jet flow property measurement was first implemented at NASA Ames in the mid-1990s. Use of TALIF expanded at NASA Ames and to NASA Johnson's arc jet facility in the late 2000s. In 2013-2014, NASA combined the agency's large-scale arc jet test capabilities at NASA Ames. Concurrent with that effort, the agency also sponsored a project to establish two comprehensive LIF diagnostic systems for the Aerodynamic Heating Facility (AHF) and Interaction Heating Facility (IHF) arc jets. The scope of the project enabled further engineering development of the existing IHF LIF system as well as the complete reconstruction of the original AHF LIF system. The updated LIF systems are identical in design and capability. They represent the culmination of over 20 years of development experience in transitioning a specialized laboratory research tool into a measurement system for large-scale, high-demand test facilities. This paper documents the overall system design from measurement requirements to implementation. Representative data from the redeveloped AHF and IHF LIF systems are also presented.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: ARC-E-DAA-TN31766 , AVIATION 2016; Jun 13, 2016 - Jun 17, 2016; Washington, DC; United States
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  • 7
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    Consolidated Laser-Induced Fluorescence Diagnostic Systems for the NASA Ames Arc Jet Facilities (2016)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The spectroscopic diagnostic technique of two photon absorption laser-induced fluorescence (TALIF) of atomic species for non-intrusive arc jet flow property measurement was first implemented at NASA Ames in the mid-1990s. Use of TALIF expanded at NASA Ames and to NASA Johnsons arc jet facility in the late 2000s. In 2013-2014, NASA combined the agency's large-scale arc jet test capabilities at NASA Ames. Concurrent with that effort, the agency also sponsored a project to establish two comprehensive LIF diagnostic systems for the Aerodynamic Heating Facility (AHF) and Interaction Heating Facility (IHF) arc jets. The scope of the project enabled further engineering development of the existing IHF LIF system as well as the complete reconstruction of the original AHF LIF system. The updated LIF systems are identical in design and capability. They represent the culmination of over 20 years of development experience in transitioning a specialized laboratory research tool into a measurement system for large-scale, high-demand test facilities. This paper documents the overall system design from measurement requirements to implementation. Representative data from the redeveloped AHF and IHF LIF systems are also presented.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: ARC-E-DAA-TN32590 , AIAA AVIATION 2016; Jun 13, 2016 - Jun 17, 2016; Washington, DC; United States
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  • 8
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    Operation of an ADR Using Helium Exchange Gas as a Substitute for a Failed Heat Switch (2014)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Soft X-ray Spectrometer (SXS) is one of four instruments on the Japanese Astro-H mission, which is currently planned for launch in late 2015. The SXS will perform imaging spectroscopy in the soft X-ray band (0.3-12 keV) using a 6 6 pixel array of microcalorimeters cooled to 50 mK. The detectors are cooled by a 3-stage adiabatic demagnetization refrigerator (ADR) that rejects heat to either a superfluid helium tank (at 1.2 K) or to a 4.5 K Joule-Thomson (JT) cryocooler. Four gas-gap heat switches are used in the assembly to manage heat flow between the ADR stages and the heat sinks. The engineering model (EM) ADR was assembled and performance tested at NASA/GSFC in November 2011, and subsequently installed in the EM dewar at Sumitomo Heavy Industries, Japan. During the first cooldown in July 2012, a failure of the heat switch that linked the two colder stages of the ADR to the helium tank was observed. Operation of the ADR requires some mechanism for thermally linking the salt pills to the heat sink, and then thermally isolating them. With the failed heat switch unable to perform this function, an alternate plan was devised which used carefully controlled amounts of exchange gas in the dewar's guard vacuum to facilitate heat exchange. The process was successfully demonstrated in November 2012, allowing the ADR to cool the detectors to 50 mK for hold times in excess of 10 h. This paper describes the exchange-gas-assisted recycling process, and the strategies used to avoid helium contamination of the detectors at low temperature.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: GSFC-E-DAA-TN23729 , Cryogenics; 64; 207-212
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  • 9
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    Pumping and Depressurizing of Insulation Materials (2010)
    In:  CASI
    Details
    Publication Date: 2019-07-12
    Description: The Fluids Testing and Technology Branch is a group that researches and tests efficient ways to use various Cryogenic Fluids, such as Liquid Nitrogen or Liquid Helium, in ground and space systems. Their main goal is to develop new technologies involving Cryogenic temperatures as well as making sure the existing technologies are understood. During my time here a lot of insulation testing has been done which is where insulation systems are tested for cryogenic systems that are in space for long durations.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: KSC-2010-216
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  • 10
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    Determination of Complex Microcalorimeter Parameters with Impedance Measurements (2005)
    In:  Other Sources
    Details
    Publication Date: 2019-07-18
    Description: The proper understanding and modeling of a microcalorimeter s response requires the accurate knowledge of a handful of parameters, such as C, G, alpha, . . . . While a few of these, such 8s the normal state resistance and the total thermal conductance to the heat bath (G) are directly determined from the DC IV characteristics, some others, notoriously the heat capacity (C) and alpha, appear in degenerate combinations in most measurable quantities. The case of a complex microcalorimeter, i.e. one in which the absorber s heat capacity is connected by a finite thermal impedance to the sensor, and subsequently by another thermal impedance to the heat bath, results in an added ambiguity in the determination of the individual C's and G's. In general, the dependence of the microcalorimeter s complex impedance on these parameters varies with frequency. This variation allows us to determine the individual parameters by fitting the prediction of the microcalorimeter model to the impedance data. We describe in this paper our efforts at characterizing the Goddard X-ray microcalorimeters. Using the parameters determined with this method we them compare the pulse shape and noise spectra predicted by the microcalorimeter model to data taken with the same devices.
    Keywords: Fluid Mechanics and Thermodynamics
    Type: LTD 11; Jul 31, 2005 - Aug 05, 2005; Tokyo; Japan
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