Radiation Protection Course PDF

# Radiation Protection Course ## Neutron Sources - **Neutron Generator** - *D-D Reaction* emits neutron with (2 MeV) - *D-T Reaction* emits neutron with (14 MeV) - $2_1H + 2_1H → 3_2He + 1_0n$ - $3_1H + 2_1H → 4_2He + 1_0n$ - **Neutron Fluence Rate** - The intensity of a n...

# Radiation Protection Course ## Neutron Sources - **Neutron Generator** - *D-D Reaction* emits neutron with (2 MeV) - *D-T Reaction* emits neutron with (14 MeV) - $2_1H + 2_1H → 3_2He + 1_0n$ - $3_1H + 2_1H → 4_2He + 1_0n$ - **Neutron Fluence Rate** - The intensity of a neutron source is usually described by the fluence rate. - This is often and incorrectly referred to as the flux. - The neutron fluence rate (N) is the number of neutrons that pass through a specified area per unit time. - Commonly employed units for this quantity are n/cm2/s (i.e., cm-2 s-1). - The direction of the neutrons is irrelevant. ## X-rays - **X-Ray Production** - The higher the atomic number of the X-ray target, the higher the yield, the higher the electron energy the higher the higher electron energy the higher the X-ray energy. - The higher the energy of the incident electron, the higher is the X-ray energy. - X-ray decrease with increasing X-ray energy. - **X-Rays** - These are photons with low energy, in the range 120 eV to 120 keV. - They have a shorter wavelength than UV rays and longer than gamma rays. - X-radiation is also called Röntgen radiation. - Named after Wilhelm Conrad Roentgen, the discoverer of its existence, and the man who named it X-radiation. The "X" standing for an unknown type of radiation. ## Gamma radiation - **Gamma radiation** is electromagnetic radiation (gamma rays) of extremely high frequency, and thus high - **Gamma decay** occurs when a nucleus transitions from an excited state to a lower energy state by emitting a gamma ray. ## Beta radiation - This consists of a stream of electrons or positrons - **A Beta Particle,** also called beta ray or beta radiation (symbol β), is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay. There are two forms of beta decay, β- decay and β+ decay. ## Alpha radiation - This type of radiation does not consist of photons but rather, particles, more specifically He²+ particles, i.e. Helium nuclei. - **Alpha Particles,** also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be produced in other ways. - Alpha particles are named after the first letter in the Greek alphabet, α. The symbol for the alpha particle is α or α²+. - Because they are identical to helium nuclei, they are also sometimes written as 42He2+, indicating a helium ion with a +2 charge (missing its two electrons). - If the ion gains electrons from its environment, the alpha particle becomes a normal (electrically neutral) helium atom 42He. ## What is Radiation? - **Radiation:** Radiation is energy travelling through space. - Sunshine is one of the most familiar forms of radiation. - It delivers energy, light, heat and suntans. - While enjoying and depending on it, we control our exposure to it. - Beyond ultraviolet radiation from the sun, there are higher-energy kinds of radiation which are used in medicine and which we all get in low doses from space, from the air, and from the earth and rocks. - Collectively we can refer to these kinds of radiation as lonizing Radiation. - It can cause damage to matter, particularly living tissue. - At high levels it is therefore dangerous, so it is necessary to control our exposure. ## The Atom - All matter is made up of atoms. - Atoms are the smallest component of an element, comprised of three particles: protons, neutrons, and electrons. - The atom is mostly empty space and neutral protons, and neutrons in the nucleus. - The number of electrons is equal to the number of protons. - Electrons in space around the nucleus. - Extremely small. One teaspoon of water has 3 times as many atoms as the Atlantic Ocean has teaspoons of water. | Particle | Symbol | Mass (kg) | Energy (MeV) | Charge | |---|---|---|---|---| | Proton | p | 1.672 * 10^-27 | 938.2 | + | | Neutron | n | 1.675 * 10^-27 | 939.2 | 0 | | Electron | e | 0.911 * 10^-30 | 0.511 | - | ## Standard nuclear notation > mass number (A = Z + N) (N = # of neutrons) > AX > atomic number (Z = # of protons) ## Let's Practice - How many protons are in 11H? - How many neutrons are in 73Li ? - How many protons are in 178O ? - How many neutrons are in 41H? ## The Nucleus - It is the central part of an atom. - It is composed of Protons and Neutrons joining together. - It contains most of the mass of the atom. - Proton and Neutron have almost the same mass. - The number of Protons in the nucleus is called Atomic Number (Z). - The total number of Protons and Neutrons in the nucleus is called Mass Number (A). - **Protons** - Proton is positively charged particle. - The atomic number (Z) is the "ID Card" of the element. - **Neutrons** - Neutron carry NO electrical charge “neutral particle” - **Electrons** - negative electrical charge. ## The Nucleus - **Nucleons** - particles found in the nucleus of an atom - neutrons - protons - **Atomic Number (Z)** - number of protons in the nucleus - **Mass Number (A)** - sum of the number of protons and neutrons - **Isotopes** - atoms with identical atomic numbers but different mass numbers - **Nuclide** - each unique atom. ## Definitions **a- Isotopes** - Group of nuclei having same Z, such as 23592U, 23892U and 23992U. The nuclides of a chemical element may have more than one isotope. **b- Nucleon** - It is either a proton or a neutron; i-e a particle inside the nucleus. **c- Nuclide** - It is a specific nucleus with a given number of protons, P or Z and number of neutron number, N. **d- Isobars** - They are nuclides having the same mass number A. ## Wave-Particle Duality - $E=mc^2$ - $E=hf$ - $c=λf$ - $E=h\frac{c}{λ}$ ## Binding Energy - **Binding energy:** amount of energy required to separate a particle from a system of particles or to disperse all the particles of the system. - The binding energy depends on the shell, and on the element, increasing as the atomic number increases. ## Definitions **e- Isotones** - They are a group of nuclides having the same neutron number, N. **f- Isomers** - They are nuclides having same Z and A. They are remaining in excited states longer than 10^-6 second (1 µs). In this case the parent and daughter nuclei are having same Z and A. while the mass of the parent is greater than that of the daughter. An example, Ba-137 m is 2.552 minutes of life time and is usually denoted by either m (meta) or *. The Cs- 137 is a radioactive source (T = 30.17y) emits β-- particles to an isomeric state in Ba-137. **g- Mirror Nuclei** - Two nuclides having same A; the value of P in one of them equals to N in the other (Li4 and Be3) and the energy level diagrams of them are very similar. ## Ionizing vs. Non-Ionizing Radiations **Non-lonizing Radiation** - A radiation that is not as energetic as ionizing radiation and cannot remove electrons from atoms or molecules. - Examples: light, **Ionizing Radiation** - A radiation that has sufficient energy to remove electrons from atoms or molecules as it passes through matter. - Ionizing - Alpha - Beta - Gamma - X-Rays - Neutrons - Non-Ionizing - Radio waves - Microwaves - Infrared - Visible Light - Ultraviolet (UV) ## Rad - The Rad (radiation absorbed dose) is used to measure the amount of radiation absorbed by an object or person which reflects the amount of energy that radioactive sources deposit in materials through which they pass. - An absorbed dose of 1 rad means that 1 gram of material absorbed 100 ergs of energy. - 1Rad=100 ergs/g (10-2 Gy) - Where the erg (joule) is a unit of energy, and the gram (kilogram) is a unit of mass. The related international system unit is the gray (Gy), where 1 Gy is equivalent to 100 rad. ## Roentgen (R) - The Rontgen (R or r) is the unit of dose of electromagnetic radiation exposure or intensity. It is equal to the radiation intensity that will create 2.08×10^9 ion pairs in a cubic centimeter of air that is. - 1R = 2.08 × 10^9 ion pairs/cm³ - The official definition, however, is in terms of electric charge per unit mass of air: - 1R=2.58 × 10^-4 C/kg - The charge refers to the electrons liberated by ionization. ## Units of Radiation - **Radiologic units** include: - Roentgen - Rad - Rem - Curie - Electron volt ## Electron Volt - **Electron Volt (eV)** is the amount of energy by the charge of a single electron moved across an electric potential difference of one volt: - *1.602 × 10^-19 J* - **One electron volt** is equal to: - *J* ## Curie - **Curie (Ci):** The original unit used to express the decay rate of a sample of radioactive material. - **One Curie:** is that quantity of material in which 3.7x10^10 atoms disintegrate every second (3.7x10^10 Becquerel, Bq). ## Rem - The rem (Roentgen equivalent man) is the traditional unit of dose equivalent (DE) or occupational exposure. It is used to express the quantity of radiation received by radiation workers. ## Equivalent Dose - The equivalent dose is expressed in a measure called the sievert (Sv). - The weighted absorbed dose is called equivalent dose. - $H_T=\sum_R D_{T,R}W_R$ - $H_T$ = Equivalent dose to tissue T - $D_{T,R}$ = Dose to tissue T because of radiation R - $W_R$ = radiation weighting factor - 1 sievert = 100 rem. - Because the rem is a relatively large unit, typical equivalent dose is measured in millirem (mrem), 10^-3 rem, or in microsievert (µSv), 10^-6 Sv. - 1 mrem = 10 µSv.