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  • ELECTRONICS AND ELECTRICAL ENGINEERING  (3)
  • infrared detectors  (2)
  • 1
    Electronic Resource
    Electronic Resource
    An adiabatic demagnetization refrigerator for infrared bolometers (1981)
    Springer
    International journal of infrared and millimeter waves 2 (1981), S. 1083-1096 
    Details
    ISSN: 1572-9559
    Keywords: refrigeration ; infrared detectors ; bolometers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Adiabatic demagnetization refrigerators have been built and installed in small portable liquid helium cryostats to test the feasibility of this method of cooling infrared bolometric detectors to temperatures below 0.3K. Performance has been achieved which suggests that bolometer temperatures of 0.2K can be maintained for periods of ∼60 hours. Applications to sensitive infrared detection from ground based telescopes and space satellites are discussed. Design data are given which permit the evaluation of refrigerator performance for a variety of design parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01007075
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Improved fabrication techniques for infrared bolometers (1983)
    Springer
    International journal of infrared and millimeter waves 4 (1983), S. 689-706 
    Details
    ISSN: 1572-9559
    Keywords: infrared detectors ; composite bolometers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Techniques are described for producing improved infrared bolometers from doped germanium. Ion implantation and sputter metalization have been used to make ohmic electrical contacts to Ge:Ga chips. This method results in a high yield of small monolithic bolometers with very little lowfrequency noise. When one of these chips is used as the thermometric element of a composite bolometer, it must be bonded to a dielectric substrate. The thermal resistance of the conventional epoxy bond has been measured and found to be undesirably large. A procedure for soldering the chip to a metalized portion of the substrate is described which reduced this resistance. The contribution of the metal film absorber to the heat capacity of a composite bolometer has been measured. The heat capacity of a NiCr absorber at 1.3K can dominate the bolometer performance. A Bi absorber has significantly lower heat capacity. A low-temperature blackbody calibrator has been built to measure the optical responsivity of bolometers. A composite bolometer system with a throughput of ∼0.1 sr cm2 has been constructed using our new techniques. In negligible background, it has an optical NEP of $$3.6 \cdot 10^{ - 15} W/\sqrt {Hz}$$ at 1.0K with a time constant of 20 ms. The noise in this bolometer is white above 2.5 Hz and is somewhat below the value predicted by thermodynamic equilibrium theory. It is in agreement with calculations based on a recent nonequilibrium theory.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01009690
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    Paper (German National Licenses)
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  • 3
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    Parametric amplification and oscillation at 36 GHz using a point-contact Josephson junction (1977)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: The paper reports observation of doubly degenerate parametric amplification and oscillation at 36 GHz from a single point-contact Josephson junction. The experimental results agree qualitatively with theoretical calculations based on the resistively shunted junction model. The estimated noise temperature of an amplifier with 11 dB net gain is consistent with zero, but has an upper limit of 50 K. Attempts to observe parametric amplification in the singly degenerate mode with a pump frequency of 72 GHz were not successful.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics; 48; Mar. 197
    Format: text
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    NASA TECHNICAL REPORTS
  • 4
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    Near millimeter wave bandpass filters (1981)
    In:  Other Sources
    Details
    Publication Date: 2011-08-18
    Description: The properties of bandpass filters for broadband photometry are reported in the 3-12/cm frequency range. The filters are based on a combination of capacitive grids deposited on thick Mylar substrates and are designed to have very high out-of-band rejection. Low frequencies are blocked by a thick grill that consists of a hexagonal grid of circular holes in a thick metal plate.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Applied Optics; 20; Apr. 15
    Format: text
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    NASA TECHNICAL REPORTS
  • 5
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    Accurate experimental and theoretical comparisons between superconductor-insulator-superconductor mixers showing weak and strong quantum effects (1988)
    In:  Other Sources
    Details
    Publication Date: 2019-07-12
    Description: A systematic study of the gain and noise in superconductor-insulator-superconductor mixers employing Ta based, Nb based, and Pb-alloy based tunnel junctions was made. These junctions displayed both weak and strong quantum effects at a signal frequency of 33 GHz. The effects of energy gap sharpness and subgap current were investigated and are quantitatively related to mixer performance. Detailed comparisons are made of the mixing results with the predictions of a three-port model approximation to the Tucker theory. Mixer performance was measured with a novel test apparatus which is accurate enough to allow for the first quantitative tests of theoretical noise predictions. It is found that the three-port model of the Tucker theory underestimates the mixer noise temperature by a factor of about 2 for all of the mixers. In addition, predicted values of available mixer gain are in reasonable agreement with experiment when quantum effects are weak. However, as quantum effects become strong, the predicted available gain diverges to infinity, which is in sharp contrast to the experimental results. Predictions of coupled gain do not always show such divergences.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: Journal of Applied Physics (ISSN 0021-8979); 63; 2479-249
    Format: text
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    NASA TECHNICAL REPORTS
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