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Title: Thermal conductivity changes upon neutron transmutation of {sup 10}B doped diamond

{sup 10}B doped p-type diamond samples were subjected to neutron transmutation reaction using thermal neutron flux of 0.9 × 10{sup 13} cm{sup −2} s{sup −1} and fast neutron flux of 0.09 × 10{sup 13} cm{sup −2} s{sup −1}. Another sample of epilayer grown on type IIa (110) single crystal diamond substrate was subjected to equal thermal and fast neutron flux of 10{sup 14} cm{sup −2} s{sup −1}. The defects in the diamond samples were previously characterized by different methods. In the present work, thermal conductivity of these diamond samples was determined at room temperature by transient thermoreflectance method. The thermal conductivity change in the samples as a function of neutron fluence is explained by the phonon scattering from the point defects and disordered regions. The thermal conductivity of the diamond samples decreased more rapidly initially and less rapidly for larger neutron fluence. In addition, the thermal conductivity in type IIb diamond decreased less rapidly with thermal neutron fluence compared to the decrease in type IIa diamond subjected to fast neutron fluence. It is concluded that the rate of production of defects during transmutation reaction is slower when thermal neutrons are used. The thermal conductivity of epilayer of diamond subjected to highmore » thermal and fast neutron fluence is associated with the covalent carbon network in the composite structure consisting of disordered carbon and sp{sup 2} bonded nanocrystalline regions.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Materials Science and Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)
  2. Nuclear Engineering, North Carolina State University, Raleigh, North Carolina 27695 (United States)
  3. Code 6174, Naval research Laboratory, Washington, District of Columbia 20375 (United States)
Publication Date:
OSTI Identifier:
22314338
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; BORON 10; COMPARATIVE EVALUATIONS; COVALENCE; DEFECTS; DIAMONDS; DOPED MATERIALS; FAST NEUTRONS; MONOCRYSTALS; NANOSTRUCTURES; NEUTRON FLUENCE; PHONONS; POINT DEFECTS; SCATTERING; SUBSTRATES; TEMPERATURE RANGE 0273-0400 K; THERMAL CONDUCTIVITY; THERMAL NEUTRONS; TRANSMUTATION