摘要 :
By operating an antineutrino detector of simple design during several fuel cycles, we observed long term changes in antineutrino flux that result from the isotopic evolution of a commercial pressurized water reactor. Measurements ...
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By operating an antineutrino detector of simple design during several fuel cycles, we observed long term changes in antineutrino flux that result from the isotopic evolution of a commercial pressurized water reactor. Measurements made with simple antineutrino detectors of this kind offer an alternative means for verifying fissile inventories at reactors, as part of International Atomic Energy Agency and other reactor safeguards regimes.
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摘要 :
The possibility of neutron and neutrino detection using water Cherenkov detectors doped with gadolinium holds the promise of constructing very large high-efficiency detectors with wide-ranging application in basic science and nati...
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The possibility of neutron and neutrino detection using water Cherenkov detectors doped with gadolinium holds the promise of constructing very large high-efficiency detectors with wide-ranging application in basic science and national security. This study addresses a major concern regarding the feasibility of such detectors: the transparency of the doped water to the ultraviolet Cherenkov light. We report on experiments conducted using a 19-m water transparency measuring instrument and associated material test tank. Sensitive measurements of the transparency of water doped with 0.2% GdCl_3 at 337,400 and 420 nm were made using this instrument. These measurements indicate that the use of GdCl_3 in stainless steel constructed water Cherenkov detectors is problematic.
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摘要 :
We present a new method to search for 0-v ββ decay in ~(136)Xe, the Ionization Imaging Chamber. This concept is based on 3-D track reconstruction by detection of ionization, without avalanche gain, in a novel time projection cha...
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We present a new method to search for 0-v ββ decay in ~(136)Xe, the Ionization Imaging Chamber. This concept is based on 3-D track reconstruction by detection of ionization, without avalanche gain, in a novel time projection chamber (TPC) geometry. The rejection efficiency of external charged particle backgrounds is optimized by the realization of a maximal, fully active, closed, and ex post facto variable fiducial surface. Event localization within the fiducial volume and detailed event reconstruction mitigate external neutral particle backgrounds; larger detectors offer higher rejection efficiencies. Energy resolution at the Q-value of 2.5 MeV is expected to be better than 1% FWHM, reducing the potential impact of allowed 2-v ββ decays. Scaling from ～25 kg prototype to 1000 + kg target mass is graceful. A new possible methodology for the identification of the daughter barium nucleus is also described. Published by Elsevier B.V.
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摘要 :
A concept for detecting the presence of special nuclear material (~(235)U or ~(239)Pu) concealed in intermodal cargo containers has been developed, studied, and recent performance results are described. It is based on interrogatio...
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A concept for detecting the presence of special nuclear material (~(235)U or ~(239)Pu) concealed in intermodal cargo containers has been developed, studied, and recent performance results are described. It is based on interrogation with a pulsed beam of 3-7 MeV neutrons that produce fission events and subsequent detection of their β-delayed neutron emission or β-delayed high-energy γ-radiation reveals the presence of fissionable material. Fission product β-delayed γ-rays above 3 MeV are nearly 10 times more abundant than β-delayed neutrons and are distinct from natural radioactivity and from nearly all of the induced activity in a normal cargo. Detector backgrounds and potential interferences with the fission signature radiation have been identified and quantified. Their impact on detection sensitivity is relatively minor and can be addressed readily. Components of a simple laboratory prototype have been assembled, tested with the most challenging cargo threat scenarios, and results compared to computer simulations. Preliminary results will be presented.
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