Results 201 to 210 of about 42,514 (244)

Visualizing cation vacancies in Ce:Gd3Al2Ga3O12 scintillators by gamma-ray-induced positron annihilation lifetime spectroscopy

Applied Physics Express, 2020
To clarify the existence of cation vacancies in Ce-doped Gd3Al2Ga3O12 (Ce:GAGG) scintillators, we performed gamma-ray-induced positron annihilation lifetime spectroscopy (GiPALS).
K. Fujimori, M. Kitaura, Y. Taira, M. Fujimoto, H. Zen, Shinta Watanabe, K. Kamada, Y. Okano, M. Katoh, M. Hosaka, J. Yamazaki, T. Hirade, Y. Kobayashi, A. Ohnishi   +13 more
semanticscholar   +1 more source

Digital positron lifetime spectroscopy at EPOS

Applied Surface Science, 2008
Abstract As the digital equipment to measure positron lifetimes gets cheaper and more widely used, it is decided that EPOS, the ELBE positron source will sample the signals from the photomultipliers directly and evaluate it online or offline by digital means.
Krille, A., Krause-Rehberg, R., Jungmann, M., Becvar, F., Brauer, G.   +4 more
openaire   +2 more sources

Annihilation Lifetime Spectroscopy Using Positrons from Bremsstrahlung Production

Defect and Diffusion Forum, 2012
A new type of a positron annihilation lifetime spectroscopy (PALS) system has been set up at the superconducting electron accelerator ELBE [ at Helmholtz-Zentrum Dresden-Rossendorf. In contrast to existing source-based PALS systems, the approach described here makes use of an intense photon beam from electron bremsstrahlung which converts through pair ...
Wagner, A., Anwand, W., Butterling, M., Cowan, T. E., Fiedler, F., Kempe, M., Krause-Rehberg, R.   +6 more
openaire   +1 more source

Slow Positron Pulsing System for Variable Energy Positron Lifetime Spectroscopy

Japanese Journal of Applied Physics, 1991
A positron pulsing system has been constructed for variable energy positron lifetime spectroscopy. The system consists of a reflection type chopper, a sub-harmonic prebuncher, and a double harmonic buncher. By operating the system with an intense slow positron beam generated by an electron linac, positron lifetime spectra have been successfully ...
Ryoichi Suzuki, Yoshinori Kobayashi, Tomohisa Mikado, Hideaki Ohgaki, Mitsukuni Chiwaki, Tetsuo Yamazaki Tetsuo Yamazaki, Takio Tomimasu Takio Tomimasu   +6 more
openaire   +1 more source

Positron lifetime spectroscopy in ordered nanoporous polymers

Journal of Polymer Science Part B: Polymer Physics, 2013
ABSTRACTPositron annihilation lifetime spectroscopy (PALS) is a common technique used to characterize the porosity of polymers. Here, we expand its use to the study of ordered nanoporous polymer monoliths. Polystyrene (PS) monoliths with aligned cylindrical pores ranging in diameters from 15 to 35 nm were examined.
Jason Engbrecht, David Green, Marc A. Hillmyer, David Olson, Eric M. Todd   +4 more
openaire   +1 more source

Preparation and positron lifetime spectroscopy of nanocrystalline metals

Nanostructured Materials, 1993
Abstract Nanocrystalline metals prepared by evaporation or sputtering with crytallite condensation and compaction were studied by means of positron lifetime spectroscopy in order to obtain information on structural free volumes in the crystallite interfaces.
R. Würschum, W. Greiner, H.-E. Schaefer
openaire   +2 more sources

Source correction in positron annihilation lifetime spectroscopy

Journal of Physics: Condensed Matter, 1996
The positron lifetimes in a source have been measured. The fraction of positrons annihilated in salt and in the Kapton supporting foils has been determined as a function of the atomic number Z of the sample. All of the experimental results have been compared with calculated values obtained from a computer program based on a Monte Carlo algorithm.
N Djourelov, M Misheva
openaire   +1 more source

Epoxide Moisture Absorption Studied by Positron Lifetime Spectroscopy

Materials Science Forum, 2012
In the last years there have been made several studies, involving many materials, with the aim of trying to explain some physical, chemical and mechanical macroscopic properties of these materials, across the study of the free volumes at the atomic and molecular scale.
J.M.M. Luís, Marco Duarte Naia, Maria Fatima Ferreira Marques, J.J.L. Morais, P.M. Gordo   +4 more
openaire   +1 more source

Amorphous hydrogenated silicon studied by positron lifetime spectroscopy

Applied Physics A Solids and Surfaces, 1986
Hydrogenated amorphous silicon (a-Si:H) prepared by dc glow discharge in silane was investigated by positron lifetime measurements at room temperature. The lifetime spectrum shows considerably longer lifetimes than in simultaneously measured Si single crystals.
H. -E. Schaefer, R. W�rschum, R. Schwarz, D. Slobodin, S. Wagner   +4 more
openaire   +1 more source

Free Volume in Poly(ether imide) Membranes Measured by Positron Annihilation Lifetime Spectroscopy and Doppler Broadening of Annihilation Radiation

Macromolecules, 2018
In order to characterize the free volume of a homologous series all-aromatic poly(ether imide) (PEI) membranes, two positron annihilation techniques were utilized: positron annihilation lifetime spectroscopy (PALS) and Doppler broadening (DB) of ...
Z. Madzarevic, H. Schut, J. Čížek, T. Dingemans   +3 more
semanticscholar   +1 more source