The resources devoted to interdicting special nuclear materials have increased considerably over the last several years in step with growing efforts to counter nuclear proliferation and nuclear terrorism. This changing landscape has led to a large amount of research and development that aims to improve the effectiveness of technology now deployed worldwide. Interdicting special nuclear materials is most commonly addressed by detecting and characterizing emitted gamma rays, but modest signature emissions can be obscured by attenuating material and must be differentiated from large and highly variable environmental background emissions. It is a daunting technical challenge to identify special nuclear materials via gamma-ray detection, but a host of new detection technologies is now emerging. This challenge motivates our review of special nuclear material signatures, the physics of detection approaches, emerging technologies, and performance metrics. The use of benchmark gamma-ray sources aids our discussion.
Revision Log and Approvals Front-end Electronics for Unattended Measurement (FEUM): Prototype Test Plan Rev. No. Date Describe Changes Pages Changed 0 11/25/14 Original Issue 1 5/20/15 Removed references to use of charge injector-Arbitrary Waverform Generator (AWG) to be use instead Removed quantitative aspects of Test 3 (Pulse Shape). Added reference AWG waveforms to Section 3. Removed ground loop noise susceptibility test (Test 22) Various edits for clarity Removed Test 9 (impedance measurements) Performance targets recalculated and updated in section 1.2 Deleted references to performing NGAM verification Added Appendix B (original IAEA specifications for FEUM) in place of original appendix B (Charge Injector Technical Specifications) Updated the digital summing test procedure Removed Test 21, Conducted EMI Susceptibility Various
The objective of the Majorana Experiment is to study neutrinoless double beta decay (0νββ) with an effective Majorana-neutrino mass sensitivity below 50 meV in order to characterize the Majorana nature of the neutrino, the Majorana mass spectrum, and the absolute mass scale. An experimental study of the neutrino mass scale implied by neutrino oscillation results is now technically within our grasp. This exciting physics goal is best pursued using the well-established technique of searching for 0νββ of 76 Ge, augmented with recent advances in signal processing and detector design. The Majorana Experiment will consist of a large mass of 76 Ge in the form of high-resolution intrinsic germanium detectors located deep underground within a low-background shielding environment. Observation of a sharp peak at the ββ endpoint will quantify the 0νββ half-life and thus the effective Majorana mass of the electron neutrino. In addition to the modest R&D program, we present here an overview of the entire project in order to help put in perspective the scope, the low level of technical risk, and the readiness of the Collaboration to immediately begin the undertaking.
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