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Associated Particle Imaging (API) is a nuclear technique that allows for the nondestructive determination of 3D isotopic distributions. The technique is based on the detection of the alpha particles associated with the neutron emitted in the deuteriumtritium (DT) fusion reaction, which provides information regarding the direction and time of the emitted 14 MeV neutron. Inelastic neutron scattering leads to characteristic gamma-ray emission from certain isotopes, for example 12C, that can be correlated with the neutron interaction location. An API system consisting of a sealed-type neutron generator, gamma detectors, and a position-sensitive alpha detector is under development for the nondestructive quantification of carbon distribution in soils. This paper describes the design of the alpha detector, detector response simulations, and first experimental results. The alpha detector consists of an Yttrium Aluminum Perovskite (YAP) scintillator mounted on the inside of a neutron generator tube. The scintillation light propagates through a sapphire window to a position-sensitive photomultiplier tube mounted on the outside. The 16 × 16 output signals are connected through a resistive network for a 4-corner readout. The four readout channels are amplified, filtered, and then digitized for the calculation of the alpha interaction in the detector. First test results demonstrate that an excellent alpha position resolution, better than the 1mm FWHM required by the application, can be achieved with this detector design.

Associated Particle Imaging (API) is a nuclear technique that allows for the nondestructive determination of 3D isotopic distributions. The technique is based on the detection of the alpha particles associated with the neutron emitted in the deuteriumtritium (DT) fusion reaction, which provides information regarding the direction and time of the emitted 14 MeV neutron. Inelastic neutron scattering leads to characteristic gamma-ray emission from certain isotopes, for example 12C, that can be correlated with the neutron interaction location. An API system consisting of a sealed-type neutron generator, gamma detectors, and a position-sensitive alpha detector is under development for the nondestructive quantification of carbon distribution in soils. This paper describes the design of the alpha detector, detector response simulations, and first experimental results. The alpha detector consists of an Yttrium Aluminum Perovskite (YAP) scintillator mounted on the inside of a neutron generator tube. The scintillation light propagates through a sapphire window to a position-sensitive photomultiplier tube mounted on the outside. The 16 × 16 output signals are connected through a resistive network for a 4-corner readout. The four readout channels are amplified, filtered, and then digitized for the calculation of the alpha interaction in the detector. First test results demonstrate that an excellent alpha position resolution, better than the 1mm FWHM required by the application, can be achieved with this detector design.

The database at http://www.radiopurity.org is the world's largest public database of material radio-purity mea-surements. These measurements are used by members of the low-background physics community to build experiments that search for neutrinos, neutrinoless double-beta decay, WIMP dark matter, and other exciting physics. This paper summarizes the current status and the future plan of this database.

The Majorana Collaboration is searching for the neutrinoless double-beta decay of the nucleus 76Ge. The Majorana Demonstrator is an array of germanium detectors deployed with the aim of implementing background reduction techniques suitable for a tonne scale 76Ge-based search (the LEGEND collaboration). In the Demonstrator, germanium detectors operate in an ultra-pure vacuum cryostat at 80 K. One special challenge of an ultra-pure environment is to develop reliable cables, connectors, and electronics that do not significantly contribute to the radioactive background of the experiment. This paper highlights the experimental requirements and how these requirements were met for the Majorana Demonstrator, including plans to upgrade the wiring for higher reliability in the summer of 2018. Also described are requirements for LEGEND R&D efforts underway to meet these additional requirements.

The Majorana Collaboration is searching for the neutrinoless double-beta decay of the nucleus 76Ge. The Majorana Demonstrator is an array of germanium detectors deployed with the aim of implementing background reduction techniques suitable for a tonne scale 76Ge-based search (the LEGEND collaboration). In the Demonstrator, germanium detectors operate in an ultra-pure vacuum cryostat at 80 K. One special challenge of an ultra-pure environment is to develop reliable cables, connectors, and electronics that do not significantly contribute to the radioactive background of the experiment. This paper highlights the experimental requirements and how these requirements were met for the Majorana Demonstrator, including plans to upgrade the wiring for higher reliability in the summer of 2018. Also described are requirements for LEGEND R&D efforts underway to meet these additional requirements.

Time-resolved experimental techniques are increasingly abundant at storage ring facilities. Recent developments in accelerator technology and beamline instrumentation allow for simultaneous operation of high-intensity and timing-based experiments. The MAX IV facility is a state-of-the-art synchrotron light source in Lund, Sweden, that will come into operation in 2016. As many storage ring facilities are pursuing upgrade programs employing strong-focusing multibend achromats and passive harmonic cavities (HCs) in high-current operation, it is of broad interest to study the accelerator and instrumentation developments required to enable timing-based experiments at such machines. In particular, the use of hybrid filling modes combined with pulse picking by resonant excitation or pseudo single bunch has shown promising results. These methods can be combined with novel beamline instrumentation, such as choppers and instrument gating. In this paper we discuss how these techniques can be implemented and employed at MAX IV.

The maximum entropy principle is a powerful tool for solving underdeterminedinverse problems. This paper considers the problem of discretizing a continuousdistribution, which arises in various applied fields. We obtain theapproximating distribution by minimizing the Kullback-Leibler information(relative entropy) of the unknown discrete distribution relative to an initialdiscretization based on a quadrature formula subject to some momentconstraints. We study the theoretical error bound and the convergence of thisapproximation method as the number of discrete points increases. We prove that(i) the theoretical error bound of the approximate expectation of any boundedcontinuous function has at most the same order as the quadrature formula westart with, and (ii) the approximate discrete distribution weakly converges tothe given continuous distribution. Moreover, we present some numerical examplesthat show the advantage of the method and apply to numerically solving anoptimal portfolio problem.