Vacancies in thermal equilibrium in Nb

Conference · Sat Jun 01 04:00:00 EDT 1985

OSTI ID:5426014

Nielsen, B; Lynn, K G; Hurst, J; Vehanen, A; Schultz, P J

We have measured the diffusion of positrons in Nb(110) in the temperature range from 300K to 2450K utilizing a variable energy positron beam. The purpose was to study the vacancy formation. However, no significant sign of vacancy trapping was observed. This could be due to a high detrapping rate caused by a low positron binding energy or due to a high vacancy formation enthalpy H/sub IV//sup F/. The last possibility is consistent with recent studies of the vacancy migration and with calculation of the positron binding energy. In this case we find the H/sub IV//sup F/ > 3 eV.

• Research Organization: Brookhaven National Lab., Upton, NY (USA); Helsinki Univ. (Finland). Dept. of Physics; Western Ontario Univ., London (Canada)
• DOE Contract Number: AC02-76CH00016
• OSTI ID: 5426014
• Report Number(s): BNL-36699; CONF-850169-18; ON: DE85014832
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
640303 -- Atomic
Molecular & Chemical Physics-- Positronium
Muonium
& Muonic & Mesic Atoms & Molecules
74 ATOMIC AND MOLECULAR PHYSICS
COLLISIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELEMENTS
HIGH TEMPERATURE
MEDIUM TEMPERATURE
METALS
NIOBIUM
PHYSICAL RADIATION EFFECTS
POINT DEFECTS
POSITRON COLLISIONS
RADIATION EFFECTS
TRANSITION ELEMENTS
TRAPPING
VACANCIES
VERY HIGH TEMPERATURE