online course, part i : an introduction to radiation

ONLINE COURSE, PART I : AN INTRODUCTION TO RADIATION

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ATOMS protons, neutrons, and electrons. Nucleus All matter is made up of atoms. The different elements are simply made up of atoms with different numbers of protons, neutrons, and electrons. Click on the different particles to learn more about them!

ATOMS protons, neutrons, and electrons. Nucleus All matter is made up of atoms. The different elements are simply made up of atoms with different numbers of protons, neutrons, and electrons. Click on the different particles to learn more about them! Back Protons : Electrical charge : + 1 Interacts with other charged particles Mass : 1.6726 10 -27 kg ~ 1 unit of mass u About the same mass as a neutron Size : 10 -15 meters 100 000 times smaller than the atom! + + + + + + - -

ATOMS protons, neutrons, and electrons. Nucleus All matter is made up of atoms. The different elements are simply made up of atoms with different numbers of protons, neutrons, and electrons. Click on the different particles to learn more about them! Back Neutrons : Electrical charge : 0 Does not interacts with other charged particles Mass : 1.6726 10 -27 kg ~ 1 unit of mass u About the same mass as a proton Size : 10 -15 meters 100 000 times smaller than the atom!

ATOMS protons, neutrons, and electrons. Nucleus All matter is made up of atoms. The different elements are simply made up of atoms with different numbers of protons, neutrons, and electrons. Click on the different particles to learn more about them! Back Electrons : Electrical charge : - 1 Interacts with other charged particles Mass : 9.1 x 10 -31 kg 2000 times less massive than protons and neutrons Size : 10 -18 meters 1000 times smaller than protons and neutrons + + - - - - - -

ATOMS protons, neutrons, and electrons. Nucleus All matter is made up of atoms. The different elements are simply made up of atoms with different numbers of protons, neutrons, and electrons. Click on the different particles to learn more about them! Back Nucleus : Electrical charge : Z (Atomic Number, number of protons) Mass : A (Mass Number, number of protons and neutrons) Size : 10 -14 meters 10 000 times smaller than the atom!

RADIOACTIVITY Unstable Atom Stable! Radiation Nuclear Forces keep the nucleus together. Weak nuclear forces unstable nucleus, needs to release energy Radiation anything emitted from an unstable nucleus Unstable atoms are called a radioactive atom, a radioisotope, or a radionuclide... Radioactive atom, radioisotope, radionuclide

Radiation Unstable Atom Stable! Nuclear Forces keep the nucleus together. Weak nuclear forces unstable nucleus, needs to release energy Radiation anything emitted from an unstable nucleus Unstable atoms are called a radioactive atom, a radioisotope, or a radionuclide Nuclear force: makes nucleons (protons and neutrons) attract Only acts on a very short scale, but powerful on that scale Large nuclei or nuclei with too few neutrons: electromagnetic force greater than the nuclear force, and the nucleus is unstable Nuclear force: makes nucleons (protons and neutrons) attract Only acts on a very short scale, but powerful on that scale Large nuclei or nuclei with too few neutrons: electromagnetic force greater than the nuclear force, and the nucleus is unstable Close RADIOACTIVITY

TYPES OF RADIOACTIVE DECAY A radioactive decay is a process in which the unstable nucleus releases energy. There are several types of radioactive decays. Click on each to lean more about them! Alpha Decay Gamma Decay Neutron Radiation Beta Decay Radioactive Decay

TYPES OF RADIOACTIVE DECAY A radioactive decay is a process in which the unstable nucleus releases energy. There are several types of radioactive decays. Click on each to lean more about them! Alpha Decay Gamma Decay Neutron Radiation Beta Decay Radioactive Decay Alpha Decays : 2 protons and 2 neutrons They are heavy and doubly charged They interact strongly with other charged particles A sheet of paper can stop them If they are ingested, inhaled or absorbed by the skin, they can be very damaging Alpha decays only occur in elements heavier than lead (Z > 82) Back Examples of alpha decays

Uranium-238 4.18 MeV Alpha Thorium-234 Radon-222Radium-226 4.77 MeV Alpha + +... EXAMPLES OF ALPHA DECAY

Uranium-238 4.18 MeV Alpha Thorium-234 Radon-222Radium-226 4.77 MeV Alpha + + This is the isotope of Uranium which contains 238 nucleons (protons and neutrons) Uranium has 92 protons, but can have between 140 and 146 neutrons Atoms with different numbers of neutrons are called isotopes Uranium-238 has 92 protons and 146 neutrons, for a total of 238 nucleons. This is the isotope of Uranium which contains 238 nucleons (protons and neutrons) Uranium has 92 protons, but can have between 140 and 146 neutrons Atoms with different numbers of neutrons are called isotopes Uranium-238 has 92 protons and 146 neutrons, for a total of 238 nucleons.... Close EXAMPLES OF ALPHA DECAY

Uranium-238 4.18 MeV Alpha Thorium-234 Radon-222Radium-226 4.77 MeV Alpha + +... This is the kinetic energy, or energy of motion, of the alpha particle. It is indicative of how much energy this particle can deposit in matter. 1 MeV = 1 000 000 eV 1 eV = 1.6 x 10 -19 J This is the kinetic energy, or energy of motion, of the alpha particle. It is indicative of how much energy this particle can deposit in matter. 1 MeV = 1 000 000 eV 1 eV = 1.6 x 10 -19 J Close EXAMPLES OF ALPHA DECAY

A radioactive decay is a process in which the unstable nucleus releases energy. There are several types of radioactive decays. Click on each to lean more about them! Alpha Decay Gamma Decay Neutron Radiation Beta Decay Radioactive Decay TYPES OF RADIOACTIVE DECAY Beta Decays: Small, charged particles emitted from the nucleus Negative beta : electron Positive beta : positron They interact electrically with other charged particles A layer of plastic or aluminum can stop beta particles Beta radiation occurs when a nucleus changes a neutron into a proton or a proton into a neutron Positive Beta Decay ( + decay) : Negative Beta Decay ( - decay) : p+p+ p+p+ n0n0 n0n0 + - p+p+ n0n0 + - Proton Neutron Electron Positron Examples of Beta Decay Back

Phosphorus-32 Beta particle (electron) Sodium-22 Beta particle (positron) Sulfur-32 Neon-22 + + EXAMPLES OF BETA DECAY

A radioactive decay is a process in which the unstable nucleus releases energy. There are several types of radioactive decays. Click on each to lean more about them! Alpha Decay Gamma Decay Neutron Radiation Beta Decay Radioactive Decay TYPES OF RADIOACTIVE DECAY Gamma decay: Energetic photon liberated from a nucleus No mass or charge, so dont change the nature of the nuclei they are emitted from Typically follow alpha or beta decays Electrically neutral, dont interact as readily with matter Only slowed down or stopped in direct collisions with electrons Thick layers of lead are required to reduce their intensity Example of gamma decays... Back

A radioactive decay is a process in which the unstable nucleus releases energy. There are several types of radioactive decays. Click on each to lean more about them! Alpha Decay Gamma Decay Neutron Radiation Beta Decay Radioactive Decay TYPES OF RADIOACTIVE DECAY Example of gamma decays Gamma decay: Energetic photon liberated from a nucleus No mass or charge, so dont change the nature of the nuclei they are emitted from Typically follow alpha or beta decays Electrically neutral, dont interact as readily with matter Only slowed down or stopped in direct collisions with electrons Thick layers of lead are required to reduce their intensity A photon is an electromagnetic wave A photon is an electromagnetic wave It has a frequency and a wavelength, which dictate its characteristics It has a frequency and a wavelength, which dictate its characteristics Visible light is photons with a certain range of wavelengths Visible light is photons with a certain range of wavelengths Less energetic photons (longer wavelengths) compose radio frequencies, microwaves and infrared light Less energetic photons (longer wavelengths) compose radio frequencies, microwaves and infrared light Higher energy photons comprise UV light, X- rays, and gamma rays. Higher energy photons comprise UV light, X- rays, and gamma rays. Close Back

Neon-22* Sodium-22 Beta particle Gamma ray Neon-22 Unstable Stable! EXAMPLE OF GAMMA DECAY

A radioactive decay is a process in which the unstable nucleus releases energy. There are several types of radioactive decays. Click on each to lean more about them! Alpha Decay Gamma Decay Neutron Radiation Beta Decay Radioactive Decay TYPES OF RADIOACTIVE DECAY Neutron radiation : Neutrons are not emitted on their own from an unstable nucleus During nuclear fission, several neutrons can be ejected They only interact with particles through direct collisions They deposit a lot of energy in collisions with single protons There are many single protons in water (hydrogen) The tissue in our body is made of 60% water Neutrons therefore deposit a lot of energy in our body Good shields : Thick layers of water, preferably heavy water Other materials heavy in hydrogen (e.g. concrete, paraffin) Example of neutron radiation Back...

A radioactive decay is a process in which the unstable nucleus releases energy. There are several types of radioactive decays. Click on each to lean more about them! Alpha Decay Gamma Decay Neutron Radiation Beta Decay Radioactive Decay TYPES OF RADIOACTIVE DECAY Neutron radiation : Neutrons are not emitted on their own from an unstable nucleus During nuclear fission, several neutrons can be ejected They only interact with particles through direct collisions They deposit a lot of energy in collisions with single protons There are many single protons in water (hydrogen) The tissue in our body is made of 60% water Neutrons therefore deposit a lot of energy in our body Good shields : Thick layers of water, preferably heavy water Other materials heavy in hydrogen (e.g. concrete, paraffin) Example of neutron radiation Back Heavy water is water in which the hydrogen atoms are made up of a proton and a neutron, instead of simply a proton. This hydrogen isotope is called deuterium. Heavy water is used in CANDU reactors. Close

Fission fragment Photon Neutron EXAMPLE OF NEUTRON RADIATION

Radiation with enough energy can knock electrons out of their orbits Alpha and beta particles strip electrons from their orbit through electric interactions Photons can give all or a fraction of their energy to electrons, liberating them from their orbit Both types of interactions result in a positive and negative piece of atom : ions Neutral Atom Positive Ion Negative Ion Replay! IONIZATION

Neutral Atom Negative Ion Positive Ion Radiation with enough energy can knock electrons out of their orbits Alpha and beta particles strip electrons from their orbit through electric interactions Photons can give all or a fraction of their energy to electrons, liberating them from their orbit Both types of interactions result in a positive and negative piece of atom : ions IONIZATION

IONIZING AND NON-IONIZING RADIATION Ionizing Radiation : radiation which can create ions Alpha, beta, gamma and X-rays are always ionizing Ions travelling through your body can break DNA and cells Poor repairs of the DNA and cells can lead to cancer. Non-ionizing radiation : photons not energetic enough to create ions Will not produce breaks in your cells and DNA, and should not lead to cancers related to radiation exposure. Radio waves MicrowavesVisible Light Infrared light Non-Ionizing Rad.... Click on the types of non- ionizing radiation to learn more!

Radio waves MicrowavesVisible Light Infrared light Non-Ionizing Rad. Click on the types of non- ionizing radiation to learn more! Ionizing Radiation : radiation which can create ions Alpha, beta, gamma and X-rays are always ionizing Ions travelling through your body can break DNA and cells Poor repairs of the DNA and cells can lead to cancer. Non-ionizing radiation : photons not energetic enough to create ions Will not produce breaks in your cells and DNA, and should not lead to cancers related to radiation exposure. X-rays are photons Very energetic Produced when electrons lose energy, e.g. when electrons interact with matter, notably with other electrons. Close IONIZING AND NON-IONIZING RADIATION

Click on the types of non- ionizing radiation to learn more! IONIZING AND NON-IONIZING RADIATION Ionizing Radiation : radiation which can create ions Alpha, beta, gamma and X-rays are always ionizing Ions travelling through your body can break DNA and cells Poor repairs of the DNA and cells can lead to cancer. Non-ionizing radiation : photons not energetic enough to create ions Will not produce breaks in your cells and DNA, and should not lead to cancers related to radiation exposure. Radio waves MicrowavesVisible Light Infrared light Non-Ionizing Rad. Microwaves : Less energetic than visible light Optimal wavelength (size) to transfer energy to water Analogous to pushing a kid on a swing If you are not at the right place, you are wasting a lot of energy Placing yourself at the end of the natural motion of the swing will allow for a maximal push Back O HH

Ionizing Radiation : radiation which can create ions Alpha, beta, gamma and X-rays are always ionizing Ions travelling through your body can break DNA and cells Poor repairs of the DNA and cells can lead to cancer. Non-ionizing radiation : photons not energetic enough to create ions Will not produce breaks in your cells and DNA, and should not lead to cancers related to radiation exposure. IONIZING AND NON-IONIZING RADIATION Radio waves MicrowavesVisible Light Infrared light Non-Ionizing Rad. Radio waves MicrowavesVisible Light Infrared light Non-Ionizing Rad. Click on the types of non- ionizing radiation to learn more! Radiowaves : Radiofrequencies are not ionizing They therefore do not break DNA strands and cells in our bodies Regardless, many research projects have investigated if there is a link between cell phone use and brain cancer. So far, the results have NOT shown a link For more information on these topics, consult the following pages : Health Canada : www.hc-sc.gc.ca/hl-vs/iyh-vsv/prod/cell-eng.phpwww.hc-sc.gc.ca/hl-vs/iyh-vsv/prod/cell-eng.php World Health Organization : www.who.int/mediacentre/factsheets/fs193/en/www.who.int/mediacentre/factsheets/fs193/en/ Back

Radio waves Click on the types of non- ionizing radiation to learn more! IONIZING AND NON-IONIZING RADIATION Ionizing Radiation : radiation which can create ions Alpha, beta, gamma and X-rays are always ionizing Ions travelling through your body can break DNA and cells Poor repairs of the DNA and cells can lead to cancer. Non-ionizing radiation : photons not energetic enough to create ions Will not produce breaks in your cells and DNA, and should not lead to cancers related to radiation exposure. MicrowavesVisible Light Infrared light Non-Ionizing Rad. Visible Light : Did you know your eyes are sensitive to as few as 5 to 9 photons? Heres some literature if you are interested : http://www.desy.de/user/projects/Physics/Quantum/see_a_photon.html Back

Radio waves MicrowavesVisible Light Infrared light Non-Ionizing Rad. Click on the types of non- ionizing radiation to learn more! IONIZING AND NON-IONIZING RADIATION Ionizing Radiation : radiation which can create ions Alpha, beta, gamma and X-rays are always ionizing Ions travelling through your body can break DNA and cells Poor repairs of the DNA and cells can lead to cancer. Non-ionizing radiation : photons not energetic enough to create ions Will not produce breaks in your cells and DNA, and should not lead to cancers related to radiation exposure. MicrowavesVisible Light Infrared light Non-Ionizing Rad. Infrared Light: Our eyes cannot see infrared photons, but our body can still sense them Infrared light is essentially heat Slightly less energetic than red light Reason why oven elements glow red Courtesy NASA/JPL-Caltech Electromagnetic Spectrum Energy Increasing Back

SUMMARY The atom is made up of a small nucleus at its centre, with electrons orbiting around it. The nucleus, in turn, is made up of protons and neutrons. An unstable nucleus will try to become stable by undergoing radioactive decay. During this process, different types of particles can be emitted: alpha, beta or gamma. During fission, neutrons can also be emitted X-rays are not produced by unstable particles, but by electrons losing energy. Ionization is the process of creating ions, in other words breaking up an electrically neutral atom or molecule into a positive component and a negative one. Alpha, beta, gamma and X-ray radiation are always ionizing. Examples of non- ionizing radiation are radiowaves, microwaves, visible light, and infrared light.

QUIZ 1. All types of radiation are dangerous and exposure to them can lead to cancer. True False

1. All types of radiation are dangerous and exposure to them can lead to cancer. True False Wrong. The minimum energy required for ionization is 34 eV. Any radiation from photons with energies below that cannot ionize matter, therefore cannot break atoms in your body, kill cells, or induce mutations. Examples of radiation which do not cause damage are visible light, infrared light, microwaves and radiofrequencies. Try again! QUIZ

1. All types of radiation are dangerous and exposure to them can lead to cancer. True False Good ! The minimum energy required for ionization is 34 eV. Any radiation from photons with energies below that cannot ionize matter, therefore cannot break atoms in your body, kill cells, or induce mutations. Examples of unharmful radiation are visible light, infrared light, microwaves and radiofrequencies. Continue QUIZ

2. Beta particles are : Bundles of energy, also known as photons Made up of two protons and two neutrons, in other words the nucleus of Helium Small, charged particles. Examples are electrons and positrons. Neutral hadrons, the most common being neutrons QUIZ

2. Beta particles are : Bundles of energy, also known as photons Made up of two protons and two neutrons, in other words the nucleus of Helium Small, charged particles. Examples are electrons and positrons. Neutral hadrons, the most common being neutrons Wrong. Gamma rays are photon. Beta particles arent. Try again! QUIZ

2. Beta particles are : Bundles of energy, also known as photons Made up of two protons and two neutrons, in other words the nucleus of Helium Small, charged particles. Examples are electrons and positrons. Neutral hadrons, the most common being neutrons Wrong. Those are alpha particles. QUIZ Try again!

2. Beta particles are : Bundles of energy, also known as photons Made up of two protons and two neutrons, in other words the nucleus of Helium Small, charged particles. Examples are electrons and positrons. Neutral hadrons, the most common being neutrons Good ! Remember, electrons have a negative charge, and positrons are the electrons anti- particle. In other words, they have the same mass and size than electrons, but they have an opposite charge. They are positive. Continue QUIZ

Made up of two protons and two neutrons, in other words the nucleus of Helium 2. Beta particles are : Bundles of energy, also known as photons Small, charged particles. Examples are electrons and positrons. Neutral hadrons, the most common being neutrons Wrong. QUIZ Try again!

3. Ionization : Can be produced by alpha and beta particles Results in two ions, ions being charged particles or molecules Is not produced by visible light and microwaves All of the above QUIZ

3. Ionization : Can be produced by alpha and beta particles Results in two ions, ions being charged particles or molecules Is not produced by visible light and microwaves All of the above QUIZ Youre right, but its not the complete answer... Ill give you another chance! Try again!

3. Ionization : Can be produced by alpha and beta particles Results in two ions, ions being charged particles or molecules Is not produced by visible light and microwaves All of the above QUIZ Good ! Ionization is the process of creating ions. Alpha and beta particles are always ionizing. Photons, on the other hand, have to be energetic enough to knock electrons out of orbit in order to be ionizing. Gamma Rays and X-Rays are ionizing, but visible light, microwaves, radiowaves and infrared light are examples of photons which arent energetic enough to ionize matter. Continue

4. Fission: Is the splitting of an atom Typically results in the emission of protons Only happens with Uranium atoms Is typically created by bombarding atoms with photons QUIZ

Only happens with Uranium atoms Typically results in the emission of protons Is the splitting of an atom Good ! Fission is used in nuclear power plants to produce power. The fission is induced by the bombardment of Uranium, Plutonium or Thorium nuclei by neutrons. When fission occurs, large amounts of energy are released. Continue QUIZ Is typically created by bombarding atoms with photons 4. Fission:

Is the splitting of an atom Typically results in the emission of protons Only happens with Uranium atoms Is typically created by bombarding atoms with photons Wrong. The main products of fission, along with the fission fragments and photons, are neutrons, not protons Try again! QUIZ 4. Fission:

Is the splitting of an atom Typically results in the emission of protons Only happens with Uranium atoms Is typically created by bombarding atoms with photons Wrong. Many large atoms can undergo fission, especially when bombarded with neutrons. For example, plutonium and thorium can also be used in fission reactions in nuclear reactors. QUIZ 4. Fission: Try again!

Is the splitting of an atom Typically results in the emission of protons Only happens with Uranium atoms Is typically created by bombarding atoms with photons Wrong. To induce fission, heavy isotopes are bombarded with neutrons, not photons. QUIZ 4. Fission: Try again!

5. The nucleus of Iodine-131 (53 protons, 78 neutrons) is unstable. To become stable, it changes one of its neutrons into a proton, becoming Xenon-131 (54 protons, 77 neutrons). What kind of particle is emitted from this decay? Alpha Positive beta particle (positron) Negative beta particle (electron) X-Ray QUIZ

X-Ray 5. The nucleus of Iodine-131 (53 protons, 78 neutrons) is unstable. To become stable, it changes one of its neutrons into a proton, becoming Xenon-131 (54 protons, 77 neutrons). What kind of particle is emitted from this decay? Alpha Positive beta particle (positron) Negative beta particle (electron) QUIZ Wong X-rays are created by the slowing down of electrons, not through radioactive decay. Try again!

X-Ray 5. The nucleus of Iodine-131 (53 protons, 78 neutrons) is unstable. To become stable, it changes one of its neutrons into a proton, becoming Xenon-131 (54 protons, 77 neutrons). What kind of particle is emitted from this decay? Alpha Positive beta particle (positron) Negative beta particle (electron) QUIZ Wrong. In alpha decays, the nucleus which decays looses two protons and two neutrons. Here, we only gain 1 proton and lose 1 neutron. Try again!

X-Ray 5. The nucleus of Iodine-131 (53 protons, 78 neutrons) is unstable. To become stable, it changes one of its neutrons into a proton, becoming Xenon-131 (54 protons, 77 neutrons). What kind of particle is emitted from this decay? Alpha Positive beta particle (positron) Negative beta particle (electron) QUIZ Wrong. This was a tricky question. In decays, you have to make sure that mass and charge are conserved. If a neutron, which is neutral in charge, turns into a proton, all of a sudden youve got an extra positive charge that didnt exist before. You therefore have to eject an electron, so a negative charge from the nucleus, to balance this out. (though I just gave you the answer!) Try again!

5. The nucleus of Iodine-131 (53 protons, 78 neutrons) is unstable. To become stable, it changes one of its neutrons into a proton, becoming Xenon-131 (54 protons, 77 neutrons). What kind of particle is emitted from this decay? Alpha Positive beta particle (positron) Negative beta particle (electron) Good ! In decays, you have to make sure that mass and charge are conserved. If a neutron, which is neutral in charge, turns into a proton, all of a sudden youve got an extra positive charge that didnt exist before. You therefore have to eject an electron, so a negative charge from the nucleus, to balance this out. Continue QUIZ X-Ray

Learn more : Take the second part of this online course, Radiation and Our Surroundings, which you can also find at radiationsafety.ca/online-courses. Visit our website to view our list of Professional Certificate Courses, Radiation Safety Awareness Courses, and Employee Radiation Safety Training Courses : radiationsafety.ca/workplace/education-and-training- servicesradiationsafety.ca/workplace/education-and-training- services Contact our Training Coordinator, Tara Hargreaves, at th radiationsafety ca. If you have comments or questions regarding this course, please send them to me, Claire, at ccohalan radiationsafety ca. Acknowledgements THE END

The Radiation Safety Institute of Canada wishes to express its appreciation to the following contributors of this online course : Claire Cohalan Tara Hargreaves Justin McKinnon Don Bell Reza Moridi Brian Bjorndal Ian Watson ACKNOWLEDGMENTS

online course, part i : an introduction to radiation

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different particles

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