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Multicoincidence radionuclide analysis systems consisting of light-charged-particle detectors operating in coincidence with photon spectrometers are being developed to improve the sensitivity of radionuclide analysis in field applications. Requiring charged-particle/photon coincidence provides active shielding from environmental photon sources, and mapping photon–photon events into a coincidence plane can remove photon spectroscopy interferences. List-mode data acquisition and flexible hardware design ensures that the most sensitive coincidence schemes involving β, atomic electron, γ and X-ray emissions can be used for radionuclide quantification. System hardware design and preliminary measurement data are discussed. A centerpiece component of this project, the development of analysis tools and data libraries required to perform automated multicoincidence analysis, is also described. [Copyright &y& Elsevier]

Abstract: A p-type semi-coaxial HPGe detector has been segmented by cutting, with a diamond saw, and etching four circumferential grooves through the Li-diffused dead layer. The degree of segmentation was tested using a well-collimated low-energy gamma-ray source. An analysis cut that rejected events depositing energy in more than one segment was applied to an energy interval of 2038±5keV, the region of interest (Qββ ) for 76Ge 0νββ decay experiments. This segmentation cut resulted in a reduction of the Compton continuum of 59%. [Copyright &y& Elsevier]

Abstract: The spectral analysis of simultaneously observed photons in separate detectors may provide an invaluable tool for radioisotope identification applications. A general recursive method to determine the activity of an isotope from the observed coincidence signature rate is discussed. The method coherently accounts for effects of true coincidence summing within a single detector and detection efficiencies. A verification of the approach with computer simulations is also discussed. [Copyright &y& Elsevier]

Abstract: A high-purity germanium (HPGe) crystal was operated in liquid argon (LAr) as a Compton-suppressed radiation spectrometer. Spectroscopic quality resolution of less than 1% of the full-width half-maximum of full energy deposition peaks was demonstrated. The construction of the small apparatus used to obtain these results is reported. The design concept is to use the LAr bath to both cool the germanium crystal to operating temperatures and act as a scintillating veto. The scintillation light from the LAr can veto cosmic rays, external primordial radiation, and gamma radiation that does not fully deposit within the germanium crystal. This technique was investigated for its potential impact on ultra-low-background gamma-ray spectroscopy. This work is based on a concept initially developed for future germanium-based neutrinoless double-beta decay experiments. [Copyright &y& Elsevier]