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Title: The multi-scattering model for calculations of positron spatial distribution in the multilayer stacks, useful for conventional positron measurements

The spatial distribution of positrons emitted from radioactive isotopes into stacks or layered samples is a subject of the presented report. It was found that Monte Carlo (MC) simulations using GEANT4 code are not able to describe correctly the experimental data of the positron fractions in stacks. The mathematical model was proposed for calculations of the implantation profile or positron fractions in separated layers or foils being components of a stack. The model takes into account only two processes, i.e., the positron absorption and backscattering at interfaces. The mathematical formulas were applied in the computer program called LYS-1 (layers profile analysis). The theoretical predictions of the model were in the good agreement with the results of the MC simulations for the semi infinite sample. The experimental verifications of the model were performed on the symmetrical and non-symmetrical stacks of different foils. The good agreement between the experimental and calculated fractions of positrons in components of a stack was achieved. Also the experimental implantation profile obtained using the depth scanning of positron implantation technique is very well described by the theoretical profile obtained within the proposed model. The LYS-1 program allows us also to calculate the fraction of positrons which annihilatemore » in the source, which can be useful in the positron spectroscopy.« less
Authors:
 [1] ;  [2] ;  [1]
  1. Institute of Nuclear Physics PAN, ul. Radzikowskiego 152, 31-342 Kraków (Poland)
  2. (Poland)
Publication Date:
OSTI Identifier:
22218162
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 114; Journal Issue: 7; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
97 MATHEMATICAL METHODS AND COMPUTING; ABSORPTION; ANNIHILATION; BACKSCATTERING; COMPUTER CODES; DEPTH; EMISSION; LAYERS; MATHEMATICAL MODELS; MONTE CARLO METHOD; POSITRONS; RADIOISOTOPES; SIMULATION; SPATIAL DISTRIBUTION; SPECTROSCOPY; STACKS