This book mainly deals with a systematic study on the determination of multi energetic photon interaction parameters at different γ-energies, density and thermal expansion as a function of temperature of 17 alkali halides using γ-ray attenuation technique.
This technique has been applied to alkali halides for the first time to measure thermophysical properties and linear attenuation coefficient as a function of temperature.
The results of experimental determination of attenuation coefficient, density and thermal expansion at high temperatures are presented in this book. The study of photon interaction parameters of these materials at different photon energies has also been included in this book.
Though there are considerable reports on the determination of thermal expansion of alkali halides, but the studies on variation of density and linear attenuation coefficient with temperature are lacking. The knowledge of photon interaction parameters of different materials is very useful in various fields.
Table of Contents
CHAPTER-I INTRODUCTION
1.1. General
1.2. Experimental methods to determine density
1.3. Experimental methods to determine thermal expansion
1.4. A review of earlier work on determination of thermophysical properties of materials
1.5. Interaction of radiation with matter
1.6. Introduction to gamma ray attenuation technique
1.6.1. Gamma ray densitometer
1.7. Gamma ray detection and recording
1.8. Scope of present work
CHAPTER-II EXPERIMENTAL SETUP
2.1. General
2.2. Block diagram
2.3. Principle
2.4. General requirements for the setup
2.4.1. Gamma source
2.4.2. Fabrication
2.4.3. Dimensions of lead and stainless steel items
2.4.4. Accessories fabricated
2.5. Electronic equipment and accessories
2.6. Programmable temperature controlled furnace
2.6.1. General
2.6.2. Programmable controller
2.6.3. Operator interface
2.6.4. Construction of PTC furnace
2.6.5. PTC furnace operation
2.7. Sample preparation and mounting
2.8. Construction of gamma ray densitometer setup
2.9. Installation of gamma ray densitometer setup
2.9.1. Installation
2.9.2. Alignment for good geometry
2.9.3. Standardization of gamma ray densitometer setup
CHAPTER-III MULTI – ENERGETIC PHOTON INTERACTION PARAMETERS OF ALKALI HALIDES
3.1. General
3.1.1. Mass attenuation coefficient
3.1.2. Linear attenuation coefficient
3.1.3. Effective and equivalent atomic number
3.1.4. Electron density
3.1.5. Mean free path
3.1.6. Cross-section
3.2. A review of earlier work
3.3. Objectives
3.4. Theory
3.5. Experimental
3.6. Results and discussion
CHAPTER-IV RESULTS ON THERMOPHYSICAL PROPERTIES OF Li AND Na HALIDES BY γ-RAY ATTENUATION STUDIES
4.1. General
4.2. A review of earlier work
4.3. Sample preparation
4.4. Experimental details
4.5. Results and discussion
4.5.1. LiCl
4.5.2. LiBr
4.5.3. LiF
4.5.4. NaCl
4.5.5. NaBr
4.5.6. NaF
4.5.7. NaI
CHAPTER-V RESULTS ON THERMOPHYSICAL PROPERTIES OF K, Cs AND Rb HALIDES BY γ-RAY ATTENUATION STUDIES
5.1. General
5.2. Sample preparation
5.3. Experimental details
5.4. Results and discussion
5.4.1. KCl
5.4.2. KBr
5.4.3. KF
5.4.4. KI
5.4.5. CsCl
5.4.6. CsBr
5.4.7. CsI
5.4.8. RbCl
5.4.9. RbBr
5.4.10. RbI
CHAPTER-VI SUMMARY & CONCLUSIONS
Research Objectives and Themes
The primary research objective is to systematically investigate and measure thermophysical properties — specifically density and thermal expansion — as well as multi-energetic photon interaction parameters for 17 alkali halides. The research addresses the current lack of data regarding temperature-dependent attenuation coefficients for these materials, utilizing a custom-fabricated gamma-ray densitometer.
- Design and fabrication of a programmable temperature-controlled gamma-ray densitometer.
- Determination of mass and linear attenuation coefficients across varying temperatures.
- Calculation of photon interaction parameters including effective atomic number and electron density.
- Comparative analysis of experimental data with theoretical models and established literature values.
Excerpt from the Book
1.1 General
Density and thermal expansion are fundamental thermophysical properties of solids. The study of temperature dependence of these properties is very important in understanding the temperature variation of other properties like elastic constants, refractive indices, dielectric constants, thermal conductivity, diffusion coefficients and other heat transfer dimensionless numbers.
Density of a material is its mass per unit volume. In finding out the density of a material determination of the mass is straight forward. Its physical state, whether it is a single piece or fine powder the difficulty is in determination of its volume. Hence, a number of methods have evolved for the determination of density. Thermal expansion of solids is due to the dimensional changes in a solid induced by an increase in temperature. When a solid material is heated, the atoms vibrate with increased amplitudes. The un-harmonic increase in the amplitudes results in the displacement of the effective mean positions of the atoms. This results in an increase in the separation between the atoms, causing the material to expand, hence dimensions of the material increase. If the material does not go through a phase change, the expansion can be easily related to the temperature change. The linear coefficient of thermal expansion (α) describes the relative change in length of a material per degree increase in temperature as shown in the following equation,
Chapter Summaries
CHAPTER-I INTRODUCTION: Provides the fundamental concepts of thermophysical properties and reviews existing experimental methods for their determination.
CHAPTER-II EXPERIMENTAL SETUP: Describes the design, fabrication, and calibration of the custom-built gamma-ray densitometer and the programmable temperature-controlled furnace.
CHAPTER-III MULTI – ENERGETIC PHOTON INTERACTION PARAMETERS OF ALKALI HALIDES: Explains the theoretical framework and parameters like mass attenuation, atomic cross-sections, and effective atomic numbers used in the study.
CHAPTER-IV RESULTS ON THERMOPHYSICAL PROPERTIES OF Li AND Na HALIDES BY γ-RAY ATTENUATION STUDIES: Presents the experimental results and temperature-dependent analysis for Lithium and Sodium halide samples.
CHAPTER-V RESULTS ON THERMOPHYSICAL PROPERTIES OF K, Cs AND Rb HALIDES BY γ-RAY ATTENUATION STUDIES: Details the findings and temperature-dependent behavior for Potassium, Cesium, and Rubidium halides.
CHAPTER-VI SUMMARY & CONCLUSIONS: Synthesizes the main research findings and concludes that the gamma-ray attenuation technique is a reliable, non-invasive method for these specific thermophysical studies.
Keywords
Gamma-ray attenuation, Densitometry, Alkali halides, Thermophysical properties, Thermal expansion, Mass attenuation coefficient, Effective atomic number, Photon interaction, Solid state physics, PTC furnace, Schottky defects, Electron density, Experimental physics
Frequently Asked Questions
What is the primary focus of this research?
The research focuses on the experimental determination of thermophysical properties, such as density and thermal expansion, and photon interaction parameters for 17 different alkali halide materials at high temperatures using a gamma-ray attenuation technique.
Which materials were studied?
The study investigated 17 alkali halides, including various salts of Lithium (LiCl, LiBr, LiF), Sodium (NaCl, NaBr, NaF, NaI), Potassium (KCl, KBr, KF, KI), Cesium (CsCl, CsBr, CsI), and Rubidium (RbCl, RbBr, RbI).
What is the main goal of the experimental setup?
The goal was to design and build a robust gamma-ray densitometer with a programmable temperature-controlled (PTC) furnace capable of reaching 1300 K, allowing for non-contact, high-precision measurements of solid-phase samples.
How is the attenuation coefficient measured?
The attenuation coefficient is measured by recording gamma-ray counts through a sample at various temperatures. By comparing these counts to reference counts without the sample, the physical parameters can be derived using the Beer-Lambert law.
What is the significance of the "Effective Atomic Number"?
The effective atomic number acts as a crucial parameter in radiation physics to characterize complex composite materials, helping researchers predict how these materials will interact with and shield radiation in medical and industrial applications.
Which scientific method is employed?
The work utilizes the gamma-ray attenuation technique, which uses gamma-beam probes to measure material characteristics without requiring direct thermal or physical contact with the sample during heating.
How does temperature affect the density of the studied samples?
The research observes that density generally decreases as temperature increases, a trend attributed largely to the creation of thermally generated Schottky defects in the crystalline structure.
Are the experimental results consistent with existing data?
Yes, the measured data for coefficients of thermal expansion and other parameters show good agreement with theoretical calculations and existing literature, providing strong validation for the custom-built experimental setup.
- Citar trabajo
- Mashusudhan Rao A.S. (Autor), 2014, Gamma-Ray Densitometry, Múnich, GRIN Verlag, https://www.grin.com/document/535416
