CHAPTER ONE

1. INTRODUCTION

1.1 BACKGROUND OF STUDY

German physicist, Wilhelm Conrad Roentgen, , In 1895  discovered radiation which he called X-rays—that could be used to look into the human body. This discovery heralded the medical uses of radiation, which have been expanding ever since. Roentgen was awarded the first Nobel Prize in physics in 1901 in recognition of the extraordinary services he had rendered to humanity. One year after Roentgen’s discovery, Henri Becquerel, a French scientist, put some photographic plates away in a drawer with fragments of a mineral containing uranium. When he developed them, he found to his surprise that they had been affected by radiation.

This phenomenon is called radioactivity and occurs when energy is released from an atom spontaneously and is measured today in units called becquerels (Bq) after Henri Becquerel. Soon afterwards, a young chemist, Marie Skłodowska-Curie, took the research further and was the first to coin the word radioactivity. In 1898, she and her husband Pierre Curie discovered that as uranium gave off radiation, it mysteriously turned into other elements, one of which they called polonium, after her homeland, and another they called radium, the “shining” element.

Today we know that the energy of radiation can damage living tissue, and the amount of energy deposited in living tissue is expressed in terms of a quantity called dose. The radiation dose may come from any radionuclide, or a number of radionuclides, whether they remain outside the body or irradiate it from inside, for example after being inhaled or ingested. Dose quantities are expressed in different ways depending on how much of the body and what parts of it are irradiated, whether one or many persons are exposed, and the length of the period of exposure (e.g. acute exposure). The amount of radiation energy absorbed per kilogram of tissue is called the absorbed dose and is expressed in units called grays (Gy) named after the English physicist and pioneer in radiation biology, Harold Gray. But this does not give the full picture because the same dose from alpha particles can do much more damage than that from beta particles or gamma rays. To compare absorbed doses of different types of radiation, they need to be weighted for their potential to cause certain types of biological damage.

This weighted dose is called the equivalent dose, which is evaluated in units called sieverts (Sv), named after the Swedish scientist Rolf Sievert. One sievert is 1 000 millisieverts, just as one litre is 1 000 millilitres or one meter is 1 000 millimetres. Another consideration is that some parts of the body are more vulnerable than others. For example, a given equivalent dose of radiation is more likely to cause cancer in the lung than in the liver, and the reproductive organs are of particular concern because Harold Gray (1905–1965) Rolf Sievert (1896–1966) 8 of the risk of hereditary effects. Thus, in order to compare doses when different tissues and organs are irradiated, the equivalent doses to different parts of the body are also weighted, and the result is called the effective dose, also expressed in sieverts (Sv). However, the effective dose is an indicator of the likelihood of cancer and genetic effects following lower doses and is not intended as a measure of severity of effects at higher doses. This complex system of radiation quantities is necessary to bring them into a coherent structure, allowing radiation protection experts to record individual doses consistently and comparably, which is of major importance for people working with radiation and who are occupationally exposed.

1. STATEMENT OF THE PROBLEM

Ionizing radiation causes neutral atoms or molecules to acquire either a positive or negative electrical charge. The most commonly known types of ionizing radiation are alpha, beta, gamma, X, and neutron rays. Charged-particle radiation, such as alpha or beta rays, has a direct ionizing effect; whereas neutral radiation, such as X, gamma, or neutron rays, have an indirect ionizing effect, i.e. these radiations first generate charged particles which then have the ionizing effect. This energy can be partly or wholly deposited in a suitable medium and thus produce an effect. The detection and measurement of radiation is based upon the detection and measurement of its effects in a medium, and the history of the emergence of radiation detectors is closely related to the discovery of radiation and radiation effects.

Radioactive material emits ionizing radiation without having been subject to any external influence. The type of radiation emitted and its associated energy is characteristic for the kind of radioactive substance. In many applications of radiation detectors, the object is to measure the energy distribution of the radiation (spectrometry). Although ionizing radiation has been present in nature (cosmic rays, naturally occurring radioactive materials) throughout man's history, it remained unnoticed until less than 100 years ago. Man has no specific sense which could have responded to this kind of radiation and it had not been possible for scientific initiative to develop any instruments that would have amplified a human response to that radiation, as was the case for example in the area of visible light waves (optics)

        It is interesting that the valuable possibilities of the use of X-rays for many purposes, medical and non-medical, became immediately apparent and that during the following year, 1896, over 1000 articles and more than 50 books were published on the subject. Knowledge of the new findings spread along with ignorance and scattered opposition" for instance, it was proposed "to prohibit the use of X-rays in opera glasses at theatres" or "to burn all work on the X-rays and to execute all the discoverers". One company "made a prey of ignorant women by advertising the sale of X-ray-proof underclothing. Finally several research has been carried out on nuclear physics.  But not even a single research has been carried out on measurement of alpha and beta radiation around physics complex.

1. AIMS AND OBJECTIVES OF STUDY

The main aim of the study is to examine measurement of alpha and beta radiation around physics complex. Other specific objectives of the study includes;

1. to determine the relationship between measurement of  alpha and beta radiation around physics complex.
2. to determine the factors affecting measurement of  alpha and beta radiation around physics complex.
3. to determine the extent to which measurement of  alpha and beta radiation has affected physics complex.
4. to proffer possible solutions to problems.

1.4 RESEARCH QUESTIONS

1. What is the relationship between measurement of alpha and beta radiation around physics complex?
2. What are the factors affecting measurement of alpha and beta radiation around physics complex?
3. What is the extent to which measurement of alpha and beta radiation has affected physics complex?
4. What are possible solutions to problems?
   1. SIGNIFICANCE OF STUDY

        The study on measurement of alpha and beta radiation around physic complex will be of immense benefit to the public in the sense that, it will create awareness to the entire public that measurement of alpha and beta is needed in our day to day activities especially in the educational sector physic specifically and this can also be seen in the medical fields, without the help of radiation x-ray films cannot be actualized in other to ascertain  health related issues. It will also educate the public that radiation in alpha and beta is good and at the other angle it hazardous to human health when been expose to rays, like gamma ray which is the most leading causes of cancerous diseases when detected in the hospitals.

        It will also be of added advantage to the government to create awareness to the public on some of the elements on the earth surfaces, instruments and chemicals that should not be use as this will reduced the risk of some people been a victim of dangerous radiation. Finally the study will contribute to the body of existing literature and knowledge to this field of study and basis for further research.

1. SCOPE OF STUDY

        The study on measurement of alpha and beta radiation is limited to physics complex.

1. DEFINITION OF TERMS

Alpha: Is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays.

Beta: β, appear as exponents of the random variable and control the shape of the distribution.

Radiation: Is defined as energy that travels through space or matter in the form of a particle or wave. ... Examples of particulate radiation include alpha particles, protons, beta particles, and neutrons.

Measurement: Refer to ways in which variables/numbers are defined and categorized.