Mr. Max Reiniger Profile

Max Reiniger

at Physikalisch-Technische Bundesanstalt

SPIE Involvement:

Author

Publications (2)

Proceedings Article | 11 October 2018 Presentation

The spectral and radiometric calibration of the ENMAP onboard calibration assembly (OBCA) (Conference Presentation)

Christian Monte, Max Reiniger, Christoph Baltruschat, Ingmar Müller, Richard Wachter, Ludger Wilkens, Felix Theml, Gavin Staton, Dieter Richard Taubert, Jörg Hollandt

Proceedings Volume 10785, 1078510 (2018) https://doi.org/10.1117/12.2325750

KEYWORDS: Calibration, Spectral calibration, Radio optics, Sensors, Environmental monitoring, Satellites, Imaging systems, Optical spheres, Halogens, Lamps

Read Abstract +

The Environmental Mapping and Analysis Program (EnMAP) is a German hyperspectral satellite mission to monitor and characterize the Earth’s environment. The EnMAP payload, the Hyper Spectral Imager (HSI) features an on-board calibration assembly (OBCA) which is designated to provide the optical radiation to monitor the instrument radiometric and spectral ‎stability during the ‎mission lifetime. The assembly comprises two integrating spheres in twin configuration equipped with several different optical radiation sources. The large ‎sphere made of white diffuse reflecting material is dedicated for radiometric stability ‎measurements, while the ‎small sphere, made of rare-earth doped diffuse reflecting material, is dedicated for spectral stability checks. ‎The ‎OBCA utilizes two types of optical radiation sources: ‎tungsten halogen lamps and white light LEDs. Here we report on the spectral and radiometric calibration of the OBCA qualification and flight model in the Reduced Background Calibration Facility 2 (RBCF2) of Physikalisch-Technische Bundesanstalt (PTB) [1]. The demanding requirements were to perform a calibration in air and in vacuum with an uncertainty of less than 2% with a spectral resolution of 0.1 nm over a wavelength range from 400 nm to 2500 nm not exceeding an operating time of 40 h for the halogen lamps and 100 h for the LEDs. Furthermore, a precise mapping of the OBCA exit aperture of size 2 mm by 24 mm with 1 mm sampling diameter had to be performed. For that purposes PTB developed a calibration procedure based on spectral comparisons of the OBCA with respect to dedicated vacuum radiance standards with an FTS in three wavelength ranges which were covered by three beamsplitter detector combinations. A dedicated imaging optics was designed transforming the F:3 opening of the OBCA to the F:8 opening ratio of the FTS and providing also the required small sampling area. Before and after their application, the dedicated vacuum qualified radiance standards were calibrated against the primary standards of PTB and corrected for the transition from air to vacuum and back to account for possible drifts of the sources. By this procedure a spectral and radiometric calibration of the OBCA traceable to the SI was achieved with the aspired uncertainties. [1] C. Monte et al, The new Reduced Background Calibration Facility 2 for Detectors, Cameras and Sources at the Physikalisch-Technische Bundesanstalt, Sensors, Systems, and Next-Generation Satellites SPIE 2018

Proceedings Article | 11 October 2018 Presentation

The new reduced background calibration facility 2 for infrared detectors, cameras and sources at the Physikalisch-Technische Bundesanstalt (Conference Presentation)

Christian Monte, Max Reiniger, Christoph Baltruschat, Albert Adibekyan, Berndt Gutschwager, Robert Häfner, Jörg Hollandt

Proceedings Volume 10785, 107850Z (2018) https://doi.org/10.1117/12.2325690

KEYWORDS: Calibration, Sensors, Black bodies, Cameras, Infrared radiation, Liquids, Infrared sensors, Standards development, Temperature metrology, Fourier transforms

Read Abstract +

Physikalisch-Technische Bundesanstalt (PTB) designed a new calibration facility, the Reduced Background Calibration Facility 2 (RBCF2) as the successor of the Reduced Background Calibration Facility (RBCF) [1] and brought it recently into operation. It provides traceable calibrations of space based infrared remote sensing experiments in terms of radiation temperature and spectral radiance. Traceable measurements from space require the use of calibrated stable detector systems and / or source based calibration standards on board of the satellites. In any case they should be calibrated under space like conditions to ensure traceability with the smallest possible uncertainty. The RBCF2 enables therefore the calibration of radiators and detectors and cameras under cryogenic and / or vacuum conditions. The integration of the instruments under test into the RBCF2 can be done under ISO 5 clean room conditions. The general concept of the RBCF2 is to connect different sources in the source chamber and detectors in the detector chamber via a liquid nitrogen cooled beam line. Source and detector chamber also incorporate cooling facilities. Translation units in both chambers enable the RBCF2 to compare and calibrate different sources and detectors with stable comparison instruments at cryogenic temperatures and under a common vacuum. Reference sources for comparisons are dedicated vacuum variable temperature blackbodies, the vacuum medium temperature blackbody (VMTBB, 150 °C to 430 °C), the vacuum low temperature blackbody (VLTBB, -173 °C to 177 °C), the liquid operated blackbody (LBB, -80 °C to 80 °C), the large area heatpipe blackbody (LAHBB, -60 °C to 50 °C) featuring a radiating diameter of 250 mm, the liquid nitrogen blackbody (LNBB, -196 °C) and calibrated vacuum integrating sphere radiators for UV-VIS and SWIR applications. The radiation temperatures of the reference blackbodies and the radiance of the integrating sphere radiators are traceable to the ITS-90 via the primary standards of PTB. Using the calibrated vacuum infrared standard radiation thermometer (VIRST) [2] direct calibrations of sources in terms of radiation temperature in the wavelength range from 8 µm to 14 µm can also be performed. The radiation of the reference sources and the sources under test can also be imaged on a vacuum Fourier-Transform Spectrometer (FTS) to allow spectrally resolved measurements. The FTS covers the wavelength range from 0.4 µm to 1000 µm. Here several detectors are employed, ranging from photomultipliers to liquid helium cooled bolometers. The different reference blackbodies enable measurements with respect to at least two reference temperatures, simultaneously. Hereby disturbances in the IR by background radiation resulting from inside the FTS can be effectively compensated. Sources can be also spatially mapped and characterized for the lateral distribution of their spectral radiance [3]. The flexible design of the facility allows also large aperture camera characterizations and modifications for customer needs and the measurement of directional spectral emissivities over a wide temperature and wavelength range [4]. [1] C. Monte, B. Gutschwager, J. Hollandt, The Reduced Background Calibration Facility for Detectors and Radiators at the Physikalisch-Technische Bundesanstalt, Sensors, Systems, and Next-Generation Satellites XIII, SPIE, 2009, 7474, 747414 [2] B. Gutschwager, J. Hollandt, T. Jankowski, R. Gärtner, A Vacuum Infrared Standard Radiation Thermometer at the PTB, International Journal of Thermophysics, 29, 330-340, 2008 [3] C. Monte, B. Gutschwager, A. Adibekyan, M. Kehrt, A. Ebersoldt, F. Olschewski, J. Hollandt, Radiometric calibration of the in-flight blackbody calibration system of the GLORIA interferometer Atmospheric Measurement Techniques, 2014, 7, 13-27 [4] A. Adibekyan, C. Monte, M. Kehrt, B. Gutschwager, J. Hollandt, Emissivity measurement under vacuum from 4 µm to 100 µm and from -40 °C to 450 °C at PTB, International Jounal of Thermophysics, 2015, 36, 283-289

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Keywords/Phrases

Search In:

Publication Years