摘要:

The damage produced by energetic ion implantation (100 keV < E < l MeV) in AgCl (single crystals or thin films) is mainly due to the Ag+sublattice. At liquid nitrogen temperature (LNT), the photographic process being blocked, the main defects created are identified as silver clusters. Their formation is analysed by means of the study of optical absorption spectra; this method permits cluster characterization with respect to elastic collision energy.

ISSN:0033-7579    

DOI:10.1080/00337578208223003

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Thermoluminescence (TL) and deformation luminescence (DL) studies in KC1 γ-irradiated at room temperature are reported. The roles that F-centres and their higher conglomerates on the one hand, and V2- and V3-centres as recombination centres on the other hand, play in these processes are specified. Two peaks at 2.5 eV and 3 eV are observed in the emission spectra of both TL and DL. The close relationship between TL and DL is confirmed.

ISSN:0033-7579    

DOI:10.1080/00337578208223004

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Rare earth doping of CaF2produces material which gives strong thermoluminescence signals. In an attempt to separate the influence of impurity and intrinsic defects CaF2has been implanted with ions of Ce, Dy, Mn, Ca and F. Comparisons are made with chemically doped samples and the effect of thermal treatments have been made in all cases. The cerium and dysprosium ions influence both the shallow charge trapping levels, which determine the temperature of the glow peaks, and the recombination sites which control the photon spectra.

ISSN:0033-7579    

DOI:10.1080/00337578208223005

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Thermal treatment of CaF2has a significant influence on the number and intensity of the peaks seen by thermo-luminescence. A combination of ion implants and anneal cycles leads to the conclusion that the 90°C glow peak is derived from a defect of a substitutional trivalent impurity (e.g. Ce+3) linked to an interstitial fluorine ion. Perturbations of this centre by other defects modify the centre and the glow peak temperature is raised to 110°C.

ISSN:0033-7579    

DOI:10.1080/00337578208223006

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Mechanisms of the defect creation in alkali halides induced by electronic excitation, suggested within these three decades, are surveyed, emphasizing how they are related to the overall yield of defect creation in solids. The experimental and theoretical studies which are critical check points for proposed mechanisms are discussed in detail. It is pointed out that the processes of localization of the wave functions of the electrons and holes and the conversion of localized electronic energy to the motion of the lattice atoms should be understood. The mechanisms of the dynamic motion of atoms to which the electronic energy is imparted and of the stabilization of the primary products, the neutral interstitials and vacancies in the halogen sublattice, are also discussed.

ISSN:0033-7579    

DOI:10.1080/00337578208223007

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

By means of the coherent states technique the interaction of local modes of imperfections in alkali halide crystals with charged particles emerging from an ion avalanche is investigated. The energy obtained by an imperfection and that lost by a particle on unit way due to the interaction are evaluated. Part of the excess energy of the mode relaxes through phonon processes, a smaller part of the energy is emitted by the crystal on the local mode frequency. This way during the interaction the local mode emits infrared radiation; an estimate is given concerning the intensity of this radiation. This intensity has a well-defined peak at the velocity of particles being in resonance with the local mode frequency. Using different local centres some information can be obtained about the velocity distribution of particles inside the crystal during irradiation.

ISSN:0033-7579    

DOI:10.1080/00337578208223008

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The present paper reports on experiments performed on X-ray coloured KC1 single crystals by means of dislocation photoconduction. This method makes use of the internal electric field developing in ionic crystals due to charged dislocations during their deformation. The effect of previous illuminations in the visible region on the photocurrent produced by VUV-light was also investigated, a memory effect and changes of the sign of the photocurrents were found under suitable conditions. It was shown that using visible light of high enough intensity the direction of the photocurrent produced by it also changes sign. The problems involved in the dislocation photoconduction method are discussed.

ISSN:0033-7579    

DOI:10.1080/00337578208223009

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The implantation of 230 keV carbon ions into alkali halide single crystals AX (A=Na, K, Rb, Cs; X=F, CI, Br, I) at temperatures T ⩽ 77 K gives rise to intensive, highly resolved, optical absorption bands in the visible region (2.3-2.8 eV, peak half width ∼0.004 eV). They resemble very much the Swan band system of matrix isolated C2. The influence of the matrix on the fine structure of the absorption bands is discussed. These carbon-centres are formed to a lesser extent or not at all when implanting at 200 K and 300 K, respectively. They bleach out at room temperature. Radiochemical experiments at room temperature with carbon atoms stemming from the11C(ρ, α)11C-nuclear reaction in BN/AX mixtures show the formation of carbon compounds such as CX4, CX3H, CX2H2, CXH3and CH4. Thus, the primarily formed C2-aggregate or C-X intermediates which are stable at T ⩽ 77 K, at higher temperature are gradually transformed to stable carbon-halogen compounds. The reactions of matrix isolated carbon upon dissolving the ionic crystals are of interest for the labelling of organic compounds with11C

ISSN:0033-7579    

DOI:10.1080/00337578208223010

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

(Paper presented in preliminary form at the meeting of the Fachgruppe Nuklearchemie der GDCh, September 22-26, 1980, Jülich, and at the III Simposio sobre Química Nuclear, Radioquímica y Química de Radiaciones, December 8-10, 1980, México, D.F.).

ISSN:0033-7579    

DOI:10.1080/00337578208223011

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

MgO single crystals implanted with Au+ions (180 keV, 6 1016-1017ions cm−2) and annealed at temperatures between 25°C and 1100°C, have been analysed—by optical spectrophotometry—by Rutherford back-scattering (to confirm the effective presence and to study the distribution profile of Au atoms), and by TEM and X-ray diffraction (to identify the phases precipitated by thermal treatment).

ISSN:0033-7579    

DOI:10.1080/00337578208223012

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor