Novel telescope-mounted spectral calibration source for the CFHT

1998 ◽  
Author(s):  
Barney L. Magrath ◽  
Robin Arsenault ◽  
Gregory A. Barrick ◽  
Pierre Martin ◽  
Bernt Grundseth ◽  
...  
Keyword(s):  
Calibration Source ◽  
Spectral Calibration

Helium gas jet spectral calibration of acoustic emission transducers and systems

1976 ◽  
Vol 54 (17) ◽  
pp. 1824-1830 ◽  
Author(s):  
S. L. McBride ◽  
T. S. Hutchison
Keyword(s):  
Acoustic Emission ◽  
Structural Response ◽  
Gas Jet ◽  
Spectral Information ◽  
Mechanical Contact ◽  
Calibration Source ◽  
Response Mapping ◽  
Spectral Calibration ◽  
Helium Gas ◽  
Produce System

The excitation and spectral calibration of acoustic emission systems using a helium gas jet is shown to produce system independent acoustic emission spectral information. The calibration source makes no mechanical contact with the specimen or structure under investigation and can be conveniently used for specimen or structural response mapping.

Calibration Source for Electron Cyclotron Emission Measurements

1990 ◽  
Vol 29 (Part 1, No. 9) ◽  
pp. 1824-1828 ◽  
Author(s):  
Kazuo Kawahata ◽  
Mizuki Sakamoto ◽  
Junji Fujita ◽  
Hiroshi Matsuo ◽  
Kiyomi Sakai
Keyword(s):  
Electron Cyclotron ◽  
Electron Cyclotron Emission ◽  
Calibration Source ◽  
Cyclotron Emission

scholarly journals Spectral Calibration Requirements of Radio Interferometers for Epoch of Reionisation Science with the SKA

2016 ◽  
Vol 33 ◽  
Author(s):  
Cathryn M. Trott ◽  
Randall B. Wayth
Keyword(s):  
Thermal Noise ◽  
Spectral Response ◽  
Order Term ◽  
Spectral Characteristics ◽  
Primary Beam ◽  
Noise Power ◽  
Science Data ◽  
Spectral Calibration ◽  
Fourth Order Term ◽  
Complete Frequency

AbstractSpectral features introduced by instrumental chromaticity of radio interferometers have the potential to negatively impact the ability to perform Epoch of Reionisation and Cosmic Dawn (EoR/CD) science. We describe instrument calibration choices that influence the spectral characteristics of the science data, and assess their impact on EoR/CD statistical and tomographic experiments. Principally, we consider the intrinsic spectral response of the antennas, embedded within a complete frequency-dependent primary beam response, and instrument sampling. The analysis is applied to the proposed SKA1-Low EoR/CD experiments. We provide tolerances on the smoothness of the SKA station primary beam bandpass, to meet the scientific goals of statistical and tomographic (imaging) of EoR/CD programs. Two calibration strategies are tested: (1) fitting of each fine channel independently, and (2) fitting of annth-order polynomial for each ~ 1 MHz coarse channel with (n+1)th-order residuals (n= 2, 3, 4). Strategy (1) leads to uncorrelated power in the 2D power spectrum proportional to the thermal noise power, thereby reducing the overall sensitivity. Strategy (2) leads to correlated residuals from the fitting, and residual signal power with (n+1)th-order curvature. For the residual power to be less than the thermal noise, the fractional amplitude of a fourth-order term in the bandpass across a single coarse channel must be < 2.5% (50 MHz), < 0.5% (150 MHz), < 0.8% (200 MHz). The tomographic experiment places constraints on phase residuals in the bandpass. We find that the root-mean-square variability over all stations of the change in phase across any fine channel (4.578 kHz) should not exceed 0.2 degrees.

Acoustic calibration source for photoacoustic detection cells

1985 ◽  
Vol 57 (8) ◽  
pp. 1786-1788
Author(s):  
Edward P. C. Lai ◽  
Becky L. Chan
Keyword(s):  
Calibration Source ◽  
Photoacoustic Detection ◽  
Acoustic Calibration

scholarly journals A large-area blackbody for in-flight calibration of an infrared interferometer deployed on board a long-duration balloon for stratospheric research

2018 ◽  
Vol 11 (8) ◽  
pp. 4757-4762 ◽  
Author(s):  
Friedhelm Olschewski ◽  
Christian Monte ◽  
Albert Adibekyan ◽  
Max Reiniger ◽  
Berndt Gutschwager ◽  
...  
Keyword(s):  
Temperature Scale ◽  
Environmental Research ◽  
Large Area ◽  
Atmospheric Measurements ◽  
Calibration Source ◽  
Aperture Diameter ◽  
International Temperature Scale ◽  
International Temperature ◽  
Long Duration ◽  
Better Than

Abstract. The deployment of the imaging Fourier Transform Spectrometer GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) on board a long-duration balloon for stratospheric research requires a blackbody for in-flight calibration in order to provide traceability to the International Temperature Scale (ITS-90) to ensure comparability with the results of other experiments and over time. GLORIA, which has been deployed onboard various research aircraft such as the Russian M55 Geophysica or the German HALO in the past, shall also be used for detailed atmospheric measurements in the stratosphere up to 40 km altitude. The instrument uses a two-dimensional detector array and an imaging optics with a large aperture diameter of 36 mm and an opening angle of 4.07∘ × 4.07∘ for infrared limb observations. To overfill the field of view (FOV) of the instrument, a large-area blackbody radiation sources (125 mm × 125 mm) is required for in-flight calibration. In order to meet the requirements regarding the scientific goals of the GLORIA missions, the radiance temperature of the blackbody calibration source has to be determined to better than 100 mK and the spatial temperature uniformity shall be better than 150 mK. As electrical resources on board a stratospheric balloon are very limited, the latent heat of the phase change of a eutectic material is utilized for temperature stabilization of the calibration source, such that the blackbody has a constant temperature of about −32 ∘C corresponding to a typical temperature observed in the stratosphere. The Institute for Atmospheric and Environmental Research at the University of Wuppertal designed and manufactured a prototype of the large-area blackbody for in-flight calibration of an infrared interferometer deployed on board a long-duration balloon for stratospheric research. This newly developed calibration source was tested under lab conditions as well as in a climatic and environmental test chamber in order to verify its performance especially under flight conditions. At the PTB (Physikalisch-Technische Bundesanstalt), the German national metrology institute, the spatial radiance distribution of the blackbody was determined and traceability to the International Temperature Scale (ITS-90) has been assured. In this paper the design and performance of the balloon-borne blackbody (BBB) is presented.

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