Радиационно-индуцированные изменения оптических, электрических и механических свойств стекол, диэлектриков и полупроводников

• Автор: Мохамед Арафат Мохамед Ахмед Адави
• Шифр специальности: 01.04.07
• Научная степень: Докторская
• Год защиты: 2001
• Место защиты: Дубна
• Количество страниц: 149 с. : ил

CONTENT
INTRODUCTION.
1. INTERACTION OF RADIATION WITH MATTER
1.1 The effect of gamma-rays interaction with matter
1.2 Effect of neutron irradiation on matter
1.3 The effect of heavy ion irradiation
1.4 Sputtering
2. EXPERIMENTAL SET-UP
2.1 Irradiation of materials on various sources
2.2 Methods for studying the properties of materials " in situ " and at post irradiation measurements
3. RESULTS
INFLUENCE OF NEUTRON AND GAMMA IRRADIATION ON THE PROPERTIES OF MATERIALS
3.1 Polyethylene samples
3.2 Alkali-silicate glass samples
3.3 Borosilicate samples
3.4 Polyvinyl alcohol samples
3.5 The effect of gamma irradiation on the microhardness of PVA
3.6 Mixed field effect on polyvinyl alcohol samples
3.7 Polytetrafluoroethylene samples.
3.8 Germanium doped sulphur samples (GeS).
4. INFLUENCE OF HEAVY ION IRRADIATION ON DIELECTRIC AND SEMICONDUCTOR.
4.1 The influence of heavy ion irradiation on the track formation in boron doped and natural diamond.
4.2 Damage formation in silicon irradiated with heavy ions

4.3. The influence of heavy ion irradiation on the surface phenomena in stainless steel

4.3.1 Formation of needle structure
4.3.2 The model of behaviour of stainless steel under swift heavy ion irradiation
CONCLUSION
ACKNOWLEDGMENT
REFERENCES

1. Introduction.
Although and despite of the great achievements in the releam of radiation physics some central problems are not yet satisfactory solved in this field, at least on the practical level. Among these problems the most challenging one is connected with the radiation effect on materials. As it is commonly known irradiation has different effects on matter and the result of irradiation depends sometimes quite significantly upon both the nature of the irradiated material, the sort of the ionizing radiation used, and the dose and intensity, too. Of great importance are also the conditions of irradiation, firstly the temperature and other outer macroscopic parameter. Besides, different materials react differently on the same radiation and up to now we have not any general theoretical approach to the process, except for some qualitative suggestions to predict, on the practical level, the results of such treating. Consequently we now need to investigate all materials being of interest. Such a task is difficult to carry out as being expensive, very time consuming and necessary effort should be made to investigate materials of strategic or of significant application. Such materials belonging to this class are widely used in nuclear industry, space technology, microelectronics, nano-technology etc. The appearance of the relevant research leads to the development of a new direction of investigation in the field of solid-state physics called solid-state radiation physics. This direction has fundamental scientific, cognitive value as well as wide practical, in particular technological applications. The creation of new materials and the modification of materials properties are carried out using different kinds of nuclear radiation: gamma rays, neutrons, light and heavy ions at low and high energies. Besides, a series of materials are broadly applied as radiation detectors. Therefore, it is of great practical meaning to understand what phenomena take place when irradiating the materials in order to predict the final effects and changes of their

evaporation (sputtering) under the influence of heavy ion irradiation. Furthermore, an attempt has been made to establish the criterion, which governs this effect.
2.2 Methods for studying the properties of materials " in situ " and at post irradiation measurements - The optical properties
This study has been achieved by carrying out spectrophotometric measurements. For this purpose the optical absorption and the optical transmission were measured within the wavelength range 200-900 nm (UV/Visible). The measurements were carried out by means of a Lambda-3 double beam (UV/Visible) Perkin Elmer spectrophotometer having wavelength range 190-900 nm (USA made) [106]. The optical density was then calculated from the received data. This quantity was then plotted as a function of the absorbed radiation dose at a certain wavelength. See for instance figure 7 or 17. Such functional dependence was then fitted by an approximated formula (20), which can easily characterize it, and if needed, the absorbed dose is to be easily determined from this formula.
- The electrical properties
The DC resistivity represents a significant part of the electrical characteristics and therefore, it was measured in the present work. A DC four contact bridge is used to measure the resistivity of our samples. For this purpose, the electrodes were fixed to the samples by using special silver paste in order to ensure good contact. The measurements of the potential drop between these contacts were carried out by using a USA made Keithely-616 electrometer see for example reference [ 107]. The DC electric resistivity of the samples was measured at temperatures ranging from 303 K and up to 353 K and at different doses of radiation. The logarithm of the measured value of the resistivity was then drawn as a