This paper presents a new gamma-gamma coincidence spectrometer to measure the radioactivity in environmental samples. This system, called Leda, is made of 2 HPGe and 1 NaI(Tl). The different analysis channels (single, in coincidence or in anti-coincidence) possible thanks to the digital electronics are described. Results obtained with environmental samples are shown. Despite its low efficiency, this method improves the detection limits for all emitters due to its very low background, and thus decreases the counting time.
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http://dx.doi.org/10.1016/j.apradiso.2016.12.049 | DOI Listing |
Appl Radiat Isot
March 2023
STUK-Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881 Helsinki, Finland.
A novel Compton suppression device has been developed at the Radiation and Nuclear Safety Authority of Finland to improve the sensitivity of measurements in the Gamma Laboratory. It utilizes γ-γ anticoincidence, but operates as a full coincidence system. Specific software has been developed for the sorting, visualization and analysis of list mode data produced by the multi-detector list-mode devices in the Gamma Laboratory.
View Article and Find Full Text PDFPhys Rev Lett
October 2020
Department of Physics, University of Oslo, N-0316 Oslo, Norway.
The cascading 3.21 and 4.44 MeV electric quadrupole transitions have been observed from the Hoyle state at 7.
View Article and Find Full Text PDFPhys Rev Lett
February 2020
Irfu, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France.
The low-lying energy spectrum of the extremely neutron-deficient self-conjugate (N=Z) nuclide _{44}^{88}Ru_{44} has been measured using the combination of the Advanced Gamma Tracking Array (AGATA) spectrometer, the NEDA and Neutron Wall neutron detector arrays, and the DIAMANT charged particle detector array. Excited states in ^{88}Ru were populated via the ^{54}Fe(^{36}Ar,2nγ)^{88}Ru^{*} fusion-evaporation reaction at the Grand Accélérateur National d'Ions Lourds (GANIL) accelerator complex. The observed γ-ray cascade is assigned to ^{88}Ru using clean prompt γ-γ-2-neutron coincidences in anticoincidence with the detection of charged particles, confirming and extending the previously assigned sequence of low-lying excited states.
View Article and Find Full Text PDFAppl Radiat Isot
December 2019
Department of Subatomic Physics, iThemba Laboratory for Accelerator Based Sciences (iThemba LABS), South Africa.
Traditionally, activity concentrations of naturally occurring radioactive materials (NORMs) are measured using a gamma-ray spectrometer with a single detector shielded with lead. In this measurement, a gamma-ray spectrometer comprising an array of four LaBr:Ce detectors without shielding was used. This spectrometer allowed for measurement in singles and coincidence (gamma-gamma) modes.
View Article and Find Full Text PDFPhys Rev Lett
February 2019
Physics Division, Argonne National Laboratory, Argonne, Illinois 60439, USA.
Detection of nuclear-decay γ rays provides a sensitive thermometer of nova nucleosynthesis. The most intense γ-ray flux is thought to be annihilation radiation from the β^{+} decay of ^{18}F, which is destroyed prior to decay by the ^{18}F(p,α)^{15}O reaction. Estimates of ^{18}F production had been uncertain, however, because key near-threshold levels in the compound nucleus, ^{19}Ne, had yet to be identified.
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