Measurement Of Background Radiation
(A Case Study Of Iperindo Town, Osun State)
The measurement of background radiation is a critical aspect of assessing the ambient radiation levels in a given environment. Background radiation refers to the ionizing radiation that is constantly present in our surroundings, originating from natural sources such as cosmic rays, radon gas, and radioactive materials in the Earth’s crust. It plays a fundamental role in radiation protection and nuclear safety. Scientists employ various instruments and methodologies to gauge background radiation, including dosimeters, Geiger-Muller counters, and scintillation detectors. These tools enable the quantification of radiation levels, aiding in the identification of potential radiation hazards and ensuring compliance with safety standards in nuclear facilities, medical settings, and general public spaces. Regular monitoring of background radiation is indispensable for safeguarding human health and the environment, contributing to the broader field of radiation safety and risk assessment.
Humans are exposed to radiation in their environment with or without their consent; and the exposure to natural background radiation is an unpreventable event on earth. This present study has measured the background radiation in Iperindo town as a result of mining activities from the surrounding goldmine using the Radiation scanner 500VBR. In each location, at least 5 readings were taken in order to ensure reliability of data. The mean absorbed dose rate in air was estimated to be 165.30±22.02 nGy/hr. The Annual Effective Dose rate was found to be 0.301±0.040 mSv/yr while the Excess Lifetime Cancer Risk was gotten as (1.201±0.160) x10-3. The details of the Research procedure and estimation of values are presented and analysed in this work. This work can be used as a baseline research data for further research work, serving as reference for dosimetry in the event of futuristic action against the menace of harmful radiation.
CERTIFICATION
DEDICATION
ACKNOWLEDGEMENT
ABSTRACT
LIST OF FIGURES
LIST OF TABLES
TABLE OF CONTENTS
CHAPTER ONE 1
INTRODUCTION 1
1.1 Background of Study 1
1.2 Aim of Study 2
1.3 Objectives of Study 3
1.4 Justification of Study 3
CHAPTER TWO 4
LITERATURE REVIEW 4
2.1 Theory 4
2.2 Types of Radiation 5
2.2.1 Non-ionizing Radiation 5
2.2.2 Ionizing Radiation 6
2.3 Types of Ionizing Radiation 7
2.3.1 Alpha Particles 7
2.3.2 Beta Particles 7
2.3.3 Gamma rays 7
2.3.4 X-rays 8
2.4 Sources of Ionizing Radiation 8
2.4.1 Natural Sources 8
2.4.1.1 Air 8
2.4.1.2 Cosmic Radiation 11
2.4.1.3 Food and Water 12
2.4.1.4 Terrestrial Sources 13
2.5 Man-Made Sources 13
2.5.1 Medical Treatment 14
2.5.2 Consumer Products 16
2.5.3 Occupational exposure 16
2.5.3.1 Gold Mining 17
2.6 Radiation Exposure 18
2.7 Measuring Background Radiation 19
2.7.1 Measuring Effective Radiation 19
2.7.2 Measuring Radiation Exposure 19
2.8 Radiation Detection Devices 20
2.9 Uses of Radiation 24
2.9.1 Medical Uses 24
2.9.2 Academic and Scientific Applications 25
2.9.3 Industrial Uses 26
2.9.4 Nuclear Power Plants 28
2.10 Review of Related Work 29
CHAPTER THREE 32
RESEARCH METHODOLOGY 32
3.1 Study Area 32
3.2 Choice of Site 36
3.3 Measuring Instrument 36
3.4 Research Procedure 38
3.5 Quantities to be Derived 38
CHAPTER FOUR 40
RESULTS AND DISCUSSION 40
4.1 Measurements Taken in Counts per Minute. 40
4.2 Absorbed Dose Rate in Iperindo Town 40
4.3 Annual Outdoor Effective Dose Equivalent in Iperindo 40
4.4 Excess Lifetime Cancer Risk (ELCR) 41
CHAPTER FIVE 46
CONCLUSION AND RECOMMENDATION 46
5.1 Conclusion 46
5.2 Recommendation 46
REFERENCES 47
INTRODUCTION
1.1 Background of Study
Radiation is a phenomenon that has existed way back before the world’s development and advancement in technology and has continued to evolve with mankind. This Phenomenon is generally defined as the transfer of energy in form of waves or sub-atomic particles (Garg, 2016). In our daily activities, we are exposed to a range of naturally occurring radiation either from cosmic rays, from radioactive substances (such as electronic devices or fruits), or from naturally occurring radiation in our bodies.
Some naturally occurring radioactive materials in the earth are Radium, Radon, Thorium, Uranium and Potassium, some of which exist in our blood and bones. Man-made radiation also exists through medical applications, consumer goods, and the operation of the nuclear power industry. Man-made radiation is also used in the treatment of Cancer and other diseases. (Milan et al, 2015)
Radiation is not entirely harmful as some kinds of radiation (such as Light, Radio, and Microwave) are very important parts of human life and living. For the purpose of this research work, a lot of focus will be placed on the harmful radiation known as Nuclear Background Radiation.
The modern understanding of ionizing radiation got its start in 1895 with Wilhelm Roentgen. In the process of conducting various experiments in applying currents to different vacuum tubes, he discovered that, despite covering one tube in a screen to block light, there seemed to be rays penetrating through to react with a barium solution on a screen he had placed nearby. After several experiments, including taking the first photo (of his wife’s hand and skeletal structure) with the new rays, he named them “X-Rays” temporarily as a designation of something unknown, and the name stuck.
This discovery was followed in 1896 by Henri Becquerel’s discovery that uranium salts gave off similar rays naturally. Though originally thinking that the rays were given off by phosphorescent uranium salts after prolonged exposure to the sun, he eventually abandoned this hypothesis. Through further experimentation including non-phosphorescent uranium, he instead came to recognize that it was the material itself that gave off the rays.
Although it was Henri Becquerel that discovered the phenomenon, it was his doctoral student, Marie Curie, who named it: radioactivity. She would go on to do much more pioneering work with radioactive materials, including the discovery of additional radioactive elements: thorium, polonium, and radium. She was awarded the Nobel Prize twice, once alongside Henri Becquerel and her husband Pierre in Physics for their work with radioactivity, and again years later in Chemistry for her discovery of radium and polonium. She also conducted pioneering work in radiology, developing and deploying mobile X-ray machines for the battlefields of World War I.
She died in 1934 of aplastic anaemia, probably developed from extended exposure to various radioactive materials, the dangers of which were only really understood long after most of her exposure had occurred. In fact, her papers (and even her cookbook) are still highly radioactive and many are considered unsafe to handle, stored in shielded boxes and requiring protective equipment to safely review.
1.2 Aim of Study
The aim of this study is to measure the natural background radiation level that arises as a result of the gold mine in Iperindo area of Osun State.
1.3 Objectives of Study
The specific objectives are:
I. to obtain data for absorbed dose rate by taking readings measured in Counts per minute at specific locations in Iperindo town.
II. to compute the mean outdoor effective dose equivalent and compare it with the dose limit stipulated by International Standards.
III. to use the obtained data from the mean outdoor effective dose to determine the health effect on the people residing in Iperindo town as a result of exposure to background nuclear radiation from the surrounding Gold mine.
1.4 Justification of Study
This project research is enhanced and motivated, for the purpose of creating awareness, thereby improving and even saving the lives of people, in Iperindo Town (On a small scale) and Nigeria as a whole.
Over the years, Radiation has evolved with man and technology. This evolution has seemed helpful in many areas and in several cases, dangerous. The occurrence of radiation presented as a biological risk has demonstrated the need to assess the potential risk associated with living close to a goldmine site.
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Measurement Of Background Radiation:
Background radiation refers to the ionizing radiation that is constantly present in our environment, coming from various natural and human-made sources. It is essential to measure background radiation to assess its potential health risks and ensure that radiation exposure levels are within safe limits. Here are some common methods and instruments used to measure background radiation:
- Geiger-Muller (GM) Counters: GM counters are widely used handheld devices for measuring background radiation. They work by detecting ionization events caused by radiation and producing audible clicks or electronic signals for each event. The rate of clicks or counts per unit of time indicates the radiation level. These counters are sensitive to various types of ionizing radiation, including alpha, beta, and gamma radiation.
- Scintillation Detectors: Scintillation detectors use special materials (scintillators) that emit flashes of light (scintillation) when they interact with ionizing radiation. Photomultiplier tubes or photodiodes then convert the light into electrical signals, which are used to measure radiation levels. Scintillation detectors are often used for more precise measurements and can discriminate between different types of radiation.
- Ionization Chambers: Ionization chambers are instruments that measure the number of ion pairs produced when radiation interacts with a gas-filled chamber. The electrical current produced is proportional to the radiation dose rate. Ionization chambers are commonly used for environmental and medical radiation measurements.
- Dosimeters: Dosimeters are wearable devices used to measure an individual’s cumulative radiation exposure over a period of time. They are often used by radiation workers to ensure they do not exceed their allowable radiation dose limits. Some dosimeters use materials that change color or undergo chemical reactions when exposed to radiation, and others use electronic components to record the dose.
- Environmental Monitoring Stations: These are fixed installations equipped with various radiation detectors to continuously monitor background radiation levels in a specific area. They are often used near nuclear facilities, in cities, or in regions with naturally occurring radioactive materials.
- Radon Detectors: Radon is a naturally occurring radioactive gas that can accumulate in buildings and pose a health risk. Radon detectors are specialized instruments used to measure radon levels in indoor environments.
- Neutron Detectors: Neutron detectors are used to measure neutron radiation, which is common in some industrial and nuclear settings. Boron trifluoride (BF3) detectors and helium-3 detectors are examples of instruments used for neutron detection.
- Radiation Survey Meters: These handheld devices are used for quick assessments of radiation levels in a specific area. They are commonly used by emergency responders and personnel working in nuclear facilities to ensure safe working conditions.
- Spectrometers: Radiation spectrometers are used to identify and quantify the specific types of radiation present in a given environment. Gamma-ray spectrometers, for example, can identify the energy levels of gamma radiation, helping to determine the sources of radiation.
When measuring background radiation, it’s essential to consider the specific types of radiation, such as alpha, beta, and gamma radiation, as well as the energy levels and potential sources in the environment. This information helps assess radiation risks and ensure safety standards are met.