摘要:

We have observed recently that neutron irradiation at low temperature can induce very strong changes in configurational disorder of glasses. This conclusion has been drawn from enthalpy change diagrams performed near Tg, by differential scanning calorimetry, on amorphous selenium. A progressive change was observed from a stabilized relaxation state to a highly quenched state as a function of the neutron dose. We explain these effects by a local heating process.

ISSN:0033-7579    

DOI:10.1080/00337578208216821

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

For insulators, the relationship between ion implantation and luminescence has been reviewed. Luminescence has been shown to be an important technique in the study of ion implanted layers and implantation mechanisms and the value of implantation doping in producing luminescence centres or devices has been discussed. Some particular topics have been chosen and considered to illustrate the useful relationship between luminescence and implantation. Cathodoluminescence studies have been used to investigate the importance of various implantation parameters in implantation doping. Identification of luminescence centres from post-implantation annealing treatments has led to an understanding of the lattice sites occupied by the implanted ions. The method of using optically-detected magnetic resonance (ODMR) to investigate implanted ions and the damage occurring during implantation has been illustrated by reference to phosphorus implantation in zinc selenide. The significance of depth-resolved cathodoluminescence in implantation studies has been briefly considered. Finally, the advantages of ion implantation in studying the role played by impurities in the radiation dosimeter material LiF are outlined.

ISSN:0033-7579    

DOI:10.1080/00337578208216822

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The annealing of bare thermal oxide on silicon at 400–500°C in a hydrogen bearing gas results in a reduced density of states Nssat the substrate silicon/oxide interface. Treatments of this type have played a role in MOS processing schedules for several years. However, a similar approach applied to large areas (cm2) of poly-silicon coated oxide appears to be less effective in reducing Nss. This may be due to the polysilicon acting as a partially impermeable barrier which tends to starve the substrate/oxide interface of hydrogen.

ISSN:0033-7579    

DOI:10.1080/00337578208216823

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The effect of electron and ion beam irradiation on the SiL vvAuger spectra of SiO2, Si3N4and Si-oxynitride films was measured by the relative intensity of the 92 eV signal, characteristic for the formation of “free” silicon during irradiation. While in Si-oxynitride (O/N = 0.37) the beam effects were almost negligible, some damage was found in Si3N4, but SiO2appeared to be extremely sensitive for electron and ion beam irradiation. By low energy electron loss spectroscopy (ELS) of ion bombarded SiO2and Si3N4films new electron states due to broken Si-O and Si-N bonds could be determined within the band gap of the insulators. The measured energy losses were interpreted by means of electron energy level schemes of the amorphous films.

ISSN:0033-7579    

DOI:10.1080/00337578208216824

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Energetic particles are used for inducing chemical reactions as well as for modifying the properties of materials with regard to their bulk and surface chemical behavior. The effects are partly caused by radiation damage or phase intermixing, partly by the chemical properties of the individual bombarding particles. In this contribution a survey of relevant applications of these techniques is presented:

ISSN:0033-7579    

DOI:10.1080/00337578208216825

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Simple11C-labelled molecules which are formed by hot processes following the14N(p, a)11C nuclear reactions with 13 MeV protons in cyclotron targets are of interest as precursors for the synthesis of11C-radiopharma-ceuticals. Solid targets show the advantage of greater stability against radiolysis and heat and a greater variability of chemical reactions. Frozen ammonia NH3, ammonium halides NH4X (X = F, C1, Br, I), and complex salts such as Co(NH3)eCl3have been studied as matrices. The interaction of recoil carbon atoms with the lattice constituents leads to a very differentiated spectrum of11C containing compounds. Analysis of the system is performed by gas chromatography or high performance liquid chromatography. In contrast to the situation in alkali halides, the carbon atoms react to organic compounds such as11C(NH)2-cyanamide,11CH3NH3+-methylammonium,11CH(NH2)2+-formamidinium and11C(NH2)3+-guanidinium with radiochemical yields of 40%, 80%, 30% and 65%, respectively. Even at 5 K, carbon stabilizes via H-abstraction to CNn-radicals and insertion into N-H bonds. The amount of ammonium ions interacting with the carbon depends strongly on the lattice arrangement. This could be shown by experiments in different lattice structures, using low temperature cryostats. The above mentioned products can be transferred to11C labelled compounds such as pyrimidine-derivatives and barbiturates suited for nuclear medical applications. Moreover, the behaviour of carbon impurities in ionic crystals may serve as a model for the formation of organic compounds in inorganic matter.

ISSN:0033-7579    

DOI:10.1080/00337578208216826

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A selective solar material must absorb most of the solar spectrum, principally the visible light, and reflect the IR light.

ISSN:0033-7579    

DOI:10.1080/00337578208216827

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Information concerning the effect of irradiation on the optical properties of materials in the infrared, sub-mm-and mm-wavelength regions is of increasing importance in fusion plasma diagnostics. The radiation induced transmission loss of a number of materials has therefore been investigated at wavelengths in the ranges 200 nm to 40 μm and 0.23 to 2.0 mm. The samples were irradiated with doses of up to 1010rad in a nuclear reactor. While germanium shows considerable transmission loss at doses as low as 106rad, and the transmission of TPX decreases at 109rad, other materials, e.g. fused quartz and possibly ZnSe, exhibit sufficient radiation hardness for use in fusion plasma diagnostics.

ISSN:0033-7579    

DOI:10.1080/00337578208216828

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0033-7579    

DOI:10.1080/00337578208216829

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0033-7579    

DOI:10.1080/00337578208216830

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor