COLOUR CENTRES IN OXIDESEffect of the V- ↔ V= transformation on positron annihilation lifetime spectra in MgO
نویسندگان
چکیده
— Positron annihilation lifetime spectra have been measured in MgO : OD~ containing ~ 20 ppm of isolated cation vacancies produced by electron irradiation. For the V~ <-> V transformation, the intensities of the longer-lived lifetime components were enhanced slightly when the vacancies trapped holes and reduced when holes were released.
منابع مشابه
Positron annihilation lifetime spectroscopy in nickel ferrite and iron oxide nanopowders
In this study, a positron annihilation lifetime spectrometer was set up and its resolution was optimized. The spectrometer is a fast-slow arrangement with time resolution of 250 ps. To obtain lifetime components and their intensities from analyzing positron annihilation lifetime spectrum, the Pascual software is used. Positrons are from a source of radioactive 22NaCl with 20 μCi activity enclos...
متن کاملپایداری سامانه اندازهگیری طول عمر پوزیترون و بررسی نوع و غلظت عیب ناشی از تابش الکترونهای 10 مگا الکترون ولتی بر نمونههای سیلیکونی نوع n و p
Positron annihilation lifetime spectroscopy method with valuation of non-destructive investigation of material, provides information about electron density, defect concentration, type of defects and atoms around the defects. The stability of the system was tested with a source. The time resolution of the whole system has been derived about 365 ps at FWHM. Then n- and p-type silicon samples we...
متن کاملar X iv : q ua nt - p h / 03 03 16 6 v 1 2 7 M ar 2 00 3 Orthopositronium : ’ Annihilation of positron in gaseous neon ’
On the basis of phenomenological model of the orthopositronium annihilation ‘isotope anomaly’ in gaseous neon (lifetime spectra, positrons source Na) the realistic estimation of an additinal mode (∼ 0.2%) of the orthopositronium annihilation is received. PACS: 36.10.Dr, 13.90.+i, 06.09.+v In huge volume of the data on lifetime spectra of annihilation in substance of positrons from β-decay Na Na...
متن کاملua nt - p h / 03 03 16 6 v 2 8 A pr 2 00 3 Orthopositronium : ‘ Annihilation of Positron in Gaseous Neon ’
On the basis of phenomenological model of the orthopositronium annihilation 'isotope anomaly' in gaseous neon (lifetime spectra, positrons source 22 Na) the realistic estimation of an additinal mode (∼0.2%) of the orthopositronium annihilation is received.
متن کاملWater-Vapor Sorption Processes in Nanoporous MgO-Al2O3 Ceramics: the PAL Spectroscopy Study.
The water-vapor sorption processes in nanoporous MgO-Al2O3 ceramics are studied with positron annihilation lifetime (PAL) spectroscopy employing positron trapping and positronium (Ps)-decaying modes. It is demonstrated that the longest-lived components in the four-term reconstructed PAL spectra with characteristic lifetimes near 2 and 60-70 ns can be, respectively, attributed to ortho-positroni...
متن کامل