Study of the equilibrium vacancy ensemble in aluminum using 1D- and 2D-angular correlation of annihilation radiation
One- and two-dimensional angular correlation of positron-electron annihilation radiation (1D and 2D-ACAR) data have been obtained between 293 and 903 K for single crystals of aluminum. The peak counting rates vs temperature, which were measured using the 1D-ACAR technique, provide a model independent value for the temperature dependence of the positron trapping probability. Using these results it is possible to strip out the Bloch state contribution from the observed 2D-ACAR surfaces and then compare the resulting defect ACAR surfaces to calculated 2D-ACAR surfaces for positrons annihilating from the Bloch, monovacancy, and divacancy-trapped states. The result of this comparison is that the presence of an increasing equilibrium divacancy population is consistent with the observed temperature dependence of ACAR data at high temperature in Al and that the present results when compared to earlier studies on Al indicate that the ratio of the trapping rates at divacancies and monovacancies is of order two.
- Research Organization:
- Argonne National Lab., IL (USA); Brandeis Univ., Waltham, MA (USA). Dept. of Physics; Lawrence Livermore National Lab., CA (USA); Reactor Research Centre, Kalpakkam (India)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6037089
- Report Number(s):
- UCRL-92349; CONF-850169-2; ON: DE85008967
- Resource Relation:
- Conference: 7. international conference on positron annihilation, New Delhi, India, 6 Jan 1985
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALUMINIUM
VACANCIES
ANNIHILATION
ELECTRONS
MONOCRYSTALS
POSITRONS
ANTILEPTONS
ANTIMATTER
ANTIPARTICLES
BASIC INTERACTIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
ELECTROMAGNETIC INTERACTIONS
ELEMENTARY PARTICLES
ELEMENTS
FERMIONS
INTERACTIONS
LEPTONS
METALS
POINT DEFECTS
360102* - Metals & Alloys- Structure & Phase Studies