Search

Abstract: The nuclide 241Am decays by alpha emission to 237Np. Most of the decays (84.6%) populate the excited level of 237Np with energy of 59.54keV. Digital coincidence counting was applied to standardize a solution of 241Am by alpha–gamma coincidence counting with efficiency extrapolation. Electronic discrimination was implemented with a pressurized proportional counter and the results were compared with two other independent techniques: Liquid scintillation counting using the logical sum of double coincidences in a TDCR array and defined solid angle counting taking into account activity inhomogeneity in the active deposit. The results show consistency between the three methods within a limit of a 0.3%. An ampoule of this solution will be sent to the International Reference System (SIR) during 2009. Uncertainties were analysed and compared in detail for the three applied methods. [Copyright &y& Elsevier]

The breakup of the projectile-like fragments in reactions induced by 6Li beams on a 144Sm target at energies close to the Coulomb barrier has been measured through the coincident detection of the emitted light particles. The emphasis of the measurements and the data analysis were placed in the complete characterization of the α-deuteron breakup mode by means of the identification of the breakup fragments and the determination of the total Q value, relative energy of the breakup products, and the angular distribution of their emission. Within the ranges of these variables covered by the present measurements, the results for the 6Li→d+α mode show a clear dominance of the resonant channel through the 3+ state at 2.186 MeV over other resonant and nonresonant channels. Differential cross sections as a function of the center-of-mass angles of the intermediate binary collision and of the breakup emission, as well as integrated cross sections as a function of energy, have been obtained. The data are compared with those measured for competing processes in the same system and with the results of calculations based on a dynamic classical model that describes noncapture breakup, incomplete fusion, and complete fusion. [ABSTRACT FROM AUTHOR]

The 53 Mn flux onto Earth is a quantity relevant for different extraterrestrial and astrophysical questions. It is a proxy for related fluxes, such as supernova-produced material or interplanetary dust particles. In this work, we performed a first attempt to assess the 53 Mn flux by measuring the 53 Mn/ 10 Be isotopic ratio in a 1400 L sample of molten Antarctic snow by AMS (Accelerator Mass Spectrometry). Using the 10 Be production rate in the atmosphere, an upper limit of 5.5 × 10 3 atoms cm -2 yr -1 was estimated for the deposition of extraterrestrial 53 Mn. This result is compatible with one of the two discrepant values existing in the literature., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The radionuclide (68)Ga is one of the few positron emitters that can be prepared in-house without the use of a cyclotron. It disintegrates to the ground state of (68)Zn partially by positron emission (89.1%) with a maximum energy of 1899.1 keV, and partially by electron capture (10.9%). This nuclide has been standardized in the frame of a cooperation project between the Radionuclide Metrology laboratories from CIEMAT (Spain) and CNEA (Argentina). Measurements involved several techniques: 4πβ-γ coincidences, integral gamma counting and Liquid Scintillation Counting using the triple to double coincidence ratio and the CIEMAT/NIST methods. Given the short half-life of the radionuclide assayed, a direct comparison between results from both laboratories was excluded and a comparison of experimental efficiencies of similar NaI detectors was used instead., (Copyright © 2012 Elsevier Ltd. All rights reserved.)