Positron annihilation lifetime spectroscop

MacQueen R.C., Granata R.D. (1996), A positron annihilation lifetime spectroscopic study of the corrosion protective properties of epoxy coatings . Prog. Org. Coat., 28, 97-112. 

Many spectroscopic methods, such as atomic absorption, Auger, electron spin resonance, Fourier transform infrared, laser photopyroelectrie effect, mass, Mossbauer, near infrared, nuclear magnetic resonance, positron annihilation lifetime, Raman, time-of-flight secondary mass, x-ray, x-ray photoelectron, and UV were used in various studies of PVC. The relevance and usefulness of these methods is discussed in detail elsewhere. ... 

Joshi, J. M., Sodaye, H. S., Pujari, P. K., SrisaUa, S., and Bajpal, M. B., Positron annihilation spectroscopic investigation of Al-pUlaredmontmorillonites, Catal. Lett., 51,109-112 (1998). Kansy, J., Microcomputer program for analysis of positron annihilation lifetime spectra, Nucl. 

Other optical and spectroscopic techniques are also important, including positron annihilation lifetime spectroscopy, spectroscopic ellip-sometry, confocal Raman spectroscopy, and photoluminescence spectroscopy. Surface-enhanced Raman spectroscopy has been made tunable using gold nanorods and strain control on elastomeric PDMS substrates. ... 

Chapter 6 deals with theoretical and experimental developments in the physical aging of polymer blends. In particular, aging data for polymer blends are reviewed and compared to the relevant homopolymer data. The past and present phenomenological, empirical and molecular models of aging are discussed. Enthalpic, volume, and mechanical relaxation, positron annihilation lifetime spectroscopy and other spectroscopic and scattering techniques are also considered. Then, specific examples on aging of blends are presented in systems where the effects of intermolecular interactions are important Finally, complex behaviors of aging of phase separated blends are considered. 

A broad overview of traditional methods and recent developments in experimental positron spectroscopy is presented. A discussion of the generation and detection of positrons and their annihilation radiation is followed by a survey of techniques used for positron lifetime measurement, Doppler broadening spectroscopy and angular correlation of annihilation radiation, and the opportunities presented by combining these methods (e.g. in age-momentum correlation) and/or extending their capabilities by the use of monoenergetic positron beams. Novel spectroscopic and microscopic techniques using positron beams are also described. 

A new spectroscopic method for the characterization of surface vacancy clusters is a combination of positron lifetime spectroscopy, which determines the size of vacancy clusters, and coincidence Doppler broadening of annihilation radiation, which gives information on where vacancy clusters are located [5, 6]. If these clusters are located on the surface of gold nanoparticles, namely the interface between the particle and host matrix, the surroundings of the clusters should include both particle atoms and the matrix atoms. Doppler broadening of annihilation radiation (DBAR) with two-detector coincidence should be able to reveal these atomic constituents, and therefore elucidate the location of vacancy clusters. 

The positron lifetime experiments were carried out with a fast-slow coincidence ORTEC system with a time resolution of about 230 ps full width at half maximum. A 5mCi source of Na was sandwiched between two identical samples, and the total count was one million. The temperature-dependent Doppler broadening energy spectroscopic (DBES) spectra were measured using an HP Ge detector at a counting rate of approximately 800 cps. The energy resolution of the solid-state detector was 1.5 keV at 0.511 MeV (corresponding to positron 2y annihilation peak). The total... 

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