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von Ballmoos P.,Roche Holding AG | Alvarez J.,IEEC CSIC | Barriere N.,University of California at Berkeley | Boggs S.,University of California at Berkeley | And 18 more authors.
Experimental Astronomy | Year: 2012

DUAL will study the origin and evolution of the elements and explores new frontiers of physics: extreme energies that drive powerful stellar explosions and accelerate particles to macroscopic energies; extreme densities that modify the laws of physics around the most compact objects known; and extreme fields that influence matter in a way that is unknown on Earth. The variability of these extreme objects requires continuous all-sky coverage, while detailed study demands an improvement in sensitivity over previous technologies by at least an order of magnitude. The DUAL payload is composed of an All-Sky Compton Imager (ASCI), and two optical modules, the Laue-Lens Optic (LLO) and the Coded-Mask Optic (CMO). The ASCI serves dual roles simultaneously, both as an optimal focal-plane sensor for deep observations with the optical modules and as a sensitive true all-sky telescope in its own right for all-sky surveys and monitoring. While the optical modules are located on the main satellite, the All-Sky Compton Imager is situated on a deployable structure at a distance of 30 m from the satellite. This configuration not only permits to maintain the less massive payload at the focal distance, it also greatly reduces the spacecraft-induced detector background, and, above all it provides ASCI with a continuous all-sky exposure. © 2012 Springer Science+Business Media B.V.


Von Ballmoos P.,Roche Holding AG | Alvarez J.,IEEC CSIC | Barriere N.,Space science Laboratory | Boggs S.,Space science Laboratory | And 18 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

DUAL will study the origin and evolution of the elements and explores new frontiers of physics: extreme energies that drive powerful stellar explosions and accelerate particles to macroscopic energies; extreme densities that modify the laws of physics around the most compact objects known; and extreme fields that influence matter in a way that is unknown on Earth. The variability of these extreme objects requires continuous all-sky coverage, while detailed study demands an improvement in sensitivity over previous technologies by at least an order of magnitude. The DUAL payload is composed of an All-Sky Compton Imager (ASCI), and two optical modules, the Laue-Lens Optic (LLO) and the Coded-Mask Optic (CMO). The ASCI serves dual roles simultaneously, both as an optimal focal-plane sensor for deep observations with the optical modules and as a sensitive true all-sky telescope in its own right for all-sky surveys and monitoring. While the optical modules are located on the main satellite, the All-Sky Compton Imager is situated on a deployable structure at a distance of 30 m from the satellite. This configuration not only permits to maintain the less massive payload at the focal distance, it also greatly reduces the spacecraft-induced detector background, and, above all it provides ASCI with a continuous all-sky exposure. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).


Takagi H.,Japan National Institute of Environmental Studies | Houweling S.,Netherland Institute for Space Research | Houweling S.,Institute of Marine and Atmospheric Research Utrecht | Andres R.J.,Oak Ridge National Laboratory | And 20 more authors.
Geophysical Research Letters | Year: 2014

We investigated differences in the five currently-available datasets of column-integrated CO2 concentrations (XCO2) retrieved from spectral soundings collected by Greenhouse gases Observing SATellite (GOSAT) and assessed their impact on regional CO2 flux estimates. We did so by estimating the fluxes from each of the five XCO2 datasets combined with surface-based CO2 data, using a single inversion system the five XCO2 datasets are available in raw and bias-corrected versions, and we found that the bias corrections diminish the range of the five coincident values by ∼30% on average the departures of the five individual inversion results (annual-mean regional fluxes based on XCO2-surface combined data) from the surface-data-only results were close to one another in some terrestrial regions where spatial coverage by each XCO2 dataset was similar the mean of the five annual global land uptakes was 1.7-±-0.3 GtC yr-1, and they were all smaller than the value estimated from the surface-based data alone. Key Points Differences in five recent satellite-based CO2 datasets were investigated Influence of CO2 data differences on surface CO2 flux estimation was assessed Impact on flux estimates varies with number density of available data © 2014. American Geophysical Union. All Rights Reserved.

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