摘要:

Thermally stimulated luminescence (TSL) and BaS phosphors doped with Cu and Bi has been studied by exciting with γ-rays (Co60) at room temperature (30°C). In all the cases two prominent glow peaks are observed nearly in the same temperature regions (around 200 and 300°C). The decay has been studied by storing the samples in darkness for different lengths of time after excitation. The trapping parameters, viz. trap depth(E)and frequency factor(S), are calculated from all these results which are in good agreement. It is concluded that the distribution of trapped holes in the neighbourhood of impurities and lattice imperfections is responsible for TSL emission.

ISSN:0033-7579    

DOI:10.1080/00337578308228183

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A computer program is described which attempts to simulate closely the actual processes of energy loss, deflections and backscattering of ions in a crystalline solid. Results are reported of calculations for 1 MeV He ions incident on silicon close to a ⟨110⟩ direction, both for an unreconstructed surface and at a surface which has undergone a 2 × 1 reconstruction in a conjugated-chain model. The predicted backscattered spectra differ, but not in any simple way that may be identified with differences in surface structure.

ISSN:0033-7579    

DOI:10.1080/00337578308228184

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

When niechanically polished Ge, Si, GaAs, LiNbOj, Cd-Ga-garnet, fused quartz and glass surfaces are sputtered by low energy ion beam (from 300 to 1200 eV) at an incident angle of 45°, the surfaces are found to exhibit hillock-like features. The influence of ion beam incident angle, energy, dose and target rotation on surface topography have been investigated. The analysesof hillocks by SIMS and AES show that their formation may not be due to impurity contamination caused by redeposition. A mechanism for hillock formation is proposed. This can be expressed by aformula, through which all the results can be successfully explained.

ISSN:0033-7579    

DOI:10.1080/00337578308228185

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

ESR measurements of ion implanted silicon are presented. Silicon wafers implanted with various doses of boron and arsenic ions were investigated. For unannealed samples the defect centre spectrum was established and its dependence on implantation dose was followed. From saturation effects the relation between the relaxation times of various point defects was established. For samples implanted with arsenic ions and annealed ESR signals from arsenic incorporated into the host lattice of the silicon substrate have been found.

ISSN:0033-7579    

DOI:10.1080/00337578308228186

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A peculiarity in the variation of the shape of the dechanneling function with an increase of the tilt angle has been discovered using Rutherford backscattering and characteristic X-ray methods. The discovered effect is due to the known mechanisms of dechanneling and is described qualitatively on the basis of the Focker-Plank equation.

ISSN:0033-7579    

DOI:10.1080/00337578308228187

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The xenon-sensitized photolysis of hydrogen sulphide and ethane has been performed. The rate constant of the excitation transfer from the Xe(3P1) resonance state to hydrogen sulphide and ethane has been measured to be 3 × 10−10and 4 × 10−10cm3-molec−1S−1. On the basis of the dependence of the hydrogen quantum yield on the xenon pressure at different hydrogen sulphide and ethane pressures the three-body decay of the Xe(3P1) state with xenon atoms and hydrogen sulphide or ethane taking a part in the process has been experimentally shown to have a rate constant of approximately 1 × 10−28cm6molec−2S−1. Using Collins-Lee theory confirms the reliability of this high value.

ISSN:0033-7579    

DOI:10.1080/00337578308228188

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The mechanism of the electron capture reactions in the gamma radiolysis of gaseous hydrogen sulphide has been investigated with methyl bromide and hydrogen chloride as the electron scavengers. The yields of methane and hydrogen were measured gas-chromatographically. The measurements were performed at two dose rates and in the presence of butadiene as a sulphur scavenger.

ISSN:0033-7579    

DOI:10.1080/00337578308228189

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The effect of the fluence on the evolution of the distributions of 40 keV nitrogen-ions implanted into iron has been investigated. The distributions were determined by using the15N(p, αγ)12C nuclear resonance reaction at 429 keV. The study shows a considerable reduction in the saturation areal density of ions retained, in relation to the simplest ion collection model. The mean sputtering yield for a 5–1017ions-cm−2fluence has been determined by 2 MeV-4He backscattering. Some experiments of isotopic marking by14N and15N implantations have brought some interesting features concerning the nitrogen distribution and the mixing. Two simple models were designed in order to justify our experimental results, but only one is presented here. This model is based upon a nitrogen outdiffusion linked to chemical reactions under beam.

ISSN:0033-7579    

DOI:10.1080/00337578308228190

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

The attempt of Seeger and Frank1to reinterpret the annealing in recovery Stage III in gold in terms of the mobile single interstitial is discussed. Considering the experimental data of Stage III in irradiated samples and for the annealing stage observed in quenching samples around room temperature, it is concluded that the assignment of the recovery in these two stages to two different elementary defects is unjustified. It is further demonstrated that the interpretation of recovery Stage III by interstitial migration is in conflict with the direct observations of vacancies migrating in this stage and that the interpretation of the recovery measurements in radiation doped gold by the two interstitial model leads to inconsistencies. The attempt to interpret recovery Stage III in gold by interstitial migration must therefore be rejected and the activation energy of 0.71 eV measured for this stage must be attributed to the migration energy of single vacancies.

ISSN:0033-7579    

DOI:10.1080/00337578308228191

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor

摘要:

A variety of intermetallic compounds have been irradiated with high energy ions to determine the criteria for an amorphous transformation. Those compounds with limited compositional range or solubility tend to become amorphous during irradiation, whereas those compounds with wide solubility tend to remain crystalline. This solubility criterion is consistent with the concept that a critical defect density which will result in a greater free energy of the crystal phase than the free energy of the amorphous phase is necessary for the amorphous transformation. This critical defect density is lower in those compounds that become amorphous. The ionicity criterion of Naguib and Kelly does not work for these intermetallic compounds, but the temperature criterion is probably valid and is, in fact, directly related to the proposed solubility criterion.

ISSN:0033-7579    

DOI:10.1080/00337578308228192

出版商:Taylor & Francis Group    

年代:1983

数据来源: Taylor