| 1. |
- Meixner, Margaret, et al.
(författare)
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Overview of the Origins Space telescope: Science drivers to observatory requirements
- 2018
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE. - 0277-786X .- 1996-756X. ; 10698
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Konferensbidrag (refereegranskat)abstract
- The Origins Space Telescope (OST) mission concept study is the subject of one of the four science and technology definition studies supported by NASA Headquarters to prepare for the 2020 Astronomy and Astrophysics Decadal Survey. OST will survey the most distant galaxies to discern the rise of metals and dust and to unveil the co-evolution of galaxy and blackhole formation, study the Milky Way to follow the path of water from the interstellar medium to habitable worlds in planetary systems, and measure biosignatures from exoplanets. This paper describes the science drivers and how they drove key requirements for OST Mission Concept 2, which will operate between ∼5 and ∼600 microns with a JWST sized telescope. Mission Concept 2 for the OST study optimizes the engineering for the key science cases into a powerful and more economical observatory compared to Mission Concept 1.
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| 2. |
- Jacobsson Svärd, Staffan, 1972-, et al.
(författare)
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Gamma-ray Emission Tomography: Modelling and evaluation of partial-defect testing capabilities
- 2014
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Assessment of gamma emission tomography (GET) for spent nuclear fuel verification is the task in IAEA MSP project JNT1955. In line with IAEA Safeguards R&D plan 2012-2023, the aim of this effort is to “develop more sensitive and less intrusive alternatives to existing NDA instruments to perform partial defect tests on spent fuel assemblies prior to transfer to difficult to access storage". The current viability study constitutes the first phase of three, with evaluation and decision points between each phase. Two verification objectives have been identified; (1) counting of fuel pins in tomographic images without any a priori knowledge of the fuel assembly under study, and (2) quantitative measurements of pin-by-pin properties, e.g. burnup, for the detection of anomalies and/or verification of operator-declared data.Previous measurements performed in Sweden and Finland have proven GET highly promising for detecting removed or substituted fuel pins (i.e. partial defects) in BWR and VVER-440 fuel assemblies even down to the individual fuel pin level. The current project adds to previous experiences by pursuing a quantitative assessment of the capabilities of GET for partial defect detection, across a broad range of potential IAEA applications, fuel types, and fuel parameters. A modelling and performance-evaluation framework has been developed to provide quantitative GET performance predictions, incorporating burn-up and cooling-time calculations, Monte Carlo radiation-transport and detector-response modelling, GET instrument definitions (existing and notional) and tomographic reconstruction algorithms, which use recorded gamma-ray intensities to produce cross-sectional images of the source distribution in the fuel assembly or conclusive pin-by-pin data. The framework also comprises image-processing algorithms and performance metrics that recognize the inherent trade-off between the probability of detecting missing pins and the false-alarm rate. Here, the modelling and analysis framework is described and preliminary results are presented.
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| 3. |
- White, Timothy A., et al.
(författare)
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Passive Tomography for Spent Fuel Verification: Analysis Framework and Instrument Design Study
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The potential for gamma emission tomography (GET) to detect partial defects within a spent nuclearfuel assembly is being assessed through a collaboration of Support Programs to the InternationalAtomic Energy Agency (IAEA). In the first phase of this study, two safeguards verification objectiveshave been identified. The first is the independent determination of the number of active pins that arepresent in the assembly, in the absence of a priori information. The second objective is to providequantitative measures of pin-by-pin properties, e.g. activity of key isotopes or pin attributes such ascooling time and relative burnup, for the detection of anomalies and/or verification of operator-declareddata. The efficacy of GET to meet these two verification objectives will be evaluated across a range offuel types, burnups, and cooling times, and with a target interrogation time of less than 60 minutes.The evaluation of GET viability for safeguards applications is founded on a modelling and analysisframework applied to existing and emerging GET instrument designs. Monte Carlo models of differentfuel types are used to produce simulated tomographer responses to large populations of “virtual” fuelassemblies. Instrument response data are processed by a variety of tomographic-reconstruction andimage-processing methods, and scoring metrics specific to each of the verification objectives aredefined and used to evaluate the performance of the methods. This paper will provide a description ofthe analysis framework and evaluation metrics, example performance-prediction results, and describethe design of a “universal” GET instrument intended to support the full range of verification scenariosenvisioned by the IAEA.
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