Development of accelerator-based {gamma}-ray-induced positron annihilation spectroscopy technique

Journal Article · Wed Jun 01 04:00:00 EDT 2005 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1925769· OSTI ID:20711720

Selim, F A; Wells, D P; Harmon, J F; Williams, J ^[1]

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1. Department of Physics, Idaho State University, Pocatello, Idaho 83209 (United States)

Accelerator-based {gamma}-ray-induced positron annihilation spectroscopy performs positron annihilation spectroscopy by utilizing MeV bremsstrahlung radiation generated from an accelerator (We have named the technique 'accelerator-based {gamma}-ray-induced PAS', even though 'bremsstrahlung' is more correct here than '{gamma} rays'. The reason for that is to make the name of the technique more general, since PAS may be performed by utilizing MeV {gamma} rays emitted from nuclei through the use of accelerators as described later in this article and as in the case of positron lifetime spectroscopy [F.A. Selim, D.P. Wells, and J.F. Harmon, Rev. Sci. Instrum. 76, 033905 (2005)].) instead of using positrons from radioactive sources or positron beams. MeV {gamma} rays create positrons inside the materials by pair production. The induced positrons annihilate with the material electrons emitting a 511-keV annihilation radiation. Doppler broadening spectroscopy of the 511-keV radiation provides information about open-volume defects and plastic deformation in solids. The high penetration of MeV {gamma} rays allows probing of defects at high depths in thick materials up to several centimeters, which is not possible with most of the current nondestructive techniques. In this article, a detailed description of the technique will be presented, including its benefits and limitations relative to the other nondestructive methods. Its application on the investigation of plastic deformation in thick steel alloys will be shown.

• OSTI ID: 20711720
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 11 Vol. 97; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNIHILATION
BREMSSTRAHLUNG
CRYSTAL DEFECTS
DOPPLER BROADENING
GAMMA RADIATION
KEV RANGE 100-1000
MEV RANGE 01-10
NONDESTRUCTIVE TESTING
PLASTICITY
POSITRON BEAMS
POSITRONS
SPECTROSCOPY
STEELS