Transcript Slide 1
Nuclear Science Merit Badge Workshop For the Boy Scouts of America by The Pennsylvania State University, American Nuclear Society Student Section Spring 2005 Welcome The Radiation Science and Engineering Center at Penn State Graphic by Vaughn Whisker & Breazeale Nuclear Reactor Basic Safety Rules No food, drinks or gum outside of designated areas No cell phones or pagers No cameras If you need to leave the group for any reason first ask an ANS member to escort you. Each group will have at least one member assigned to wear a dosimeter. A dosimeter is a small device to measure radiation exposure. If you read the dosimeter now it will read zero. At the end of the day it should also read zero because we are not going to take you anywhere we expect there to be significant radiation exposure. Requirement #1 Let’s Get Started ALARA Alpha Particle Atom Background Beta Particle Contamination Curie (Ci) Becquerel (Bq) Gamma Ray Half-life Ionization Quark Isotope Neutron Nuclear Energy Nuclear Reactor Particle Accelerator Rad Gray (Gy) Radiation Radioactivity Radon (Rn) Rem Sievert (Sv) X-Ray ALARA As Low As Reasonably Achievable This is the principle by which the nuclear industry operates. The goal is to minimize the radiation exposure of workers. ALARA: TIME DISTANCE SHIELDING Alpha Particle (alpha ray, alpha radiation) An electrically charged particle made of two protons and two neutrons. These are thrown off by many radioactive materials, including uranium and radium. An alpha particle is identical to the nucleus of a helium atom. Symbol: Atom The smallest piece of an element. They are made up of protons, neutrons, and electrons and the number of protons determines the kind. Background Radiation The ionizing radiation always present in nature from cosmic rays or from radioactive materials in the air, water, food, ground, building materials, and some consumer products. Beta Particle (beta ray, beta radiation) An electrically charged particle thrown off by many radioactive materials. If is a free moving electron and possesses the smallest negative charge found in nature. Beta particles come out of radioactive atoms at high speeds. Symbol: ß Contamination Radioactive material deposited or dispersed in materials or places where it is not wanted. Curie (Ci) A measure of the rate at which radioactive material throws off particles or radiation. It is named in honor of the French chemists, Marie and Pierre Curie. One curie is equal to the activity in one gram of radium. Becquerel (Bq) The SI (metric) unit of radioactivity in a material. One Bq measures one disintegration per second. Gamma Rays (gamma radiation) A form of ionizing radiation energy (the same as X-rays) given off when the nucleus of some radioactive materials disintegrate. Symbol: Half-life The amount of time it takes for one half of a group of radioactive atoms to decay. Symbol: (t1/2) Ionization A process by which atoms lose one or more electrons and are left with a positive electrical charge. Some atoms gain an electron and are negatively charged. Radiation hitting clouds (or groups) of atoms changes some of them into ions, some positive and some negative. Quark A sub-nuclear, fundamental particle of matter that makes up protons and neutrons. quark Flavor Mass (GeV/e2) Electric charge(e) u up 0.004 +2/3 d down 0.008 -1/3 c Charm 1.5 +2/3 s Strange 0.15 -1/3 t top 176 +2/3 b bottom 4.7 -1/3 Isotope Atoms of the same chemical element having the same number of protons (the same atomic number) but with a different number of neutrons (different atomic weights). Some isotopes are radioactive (radioisotopes) and some are not (stable). Neutron A basic atomic particle, having no electrical charge, found in the nucleus of atoms. It has an atomic weight of one. Nuclear Energy Energy released when the nucleus of an atom splits (fission), joins with another nucleus (fusion), or disintegrates (radiation). Nuclear energy is the most exact terms to describe the energy produced in a nuclear reactor. Nuclear Reactor A device in which a nuclear fission chain reaction takes place. Particle Accelerator An electric device for speeding up electrically charged particles such as electrons and protons. These are then used for smashing into atoms at high speeds. This allows scientists to study the particles and forces that make up atoms. RAD A unit of measure of how much radiation energy something absorbs when exposed to a radiation source. Gray (Gy) The SI (metric) equivalent of a rad. One gray is equal to 100 rads. Radiation The energetic particles or rays thrown out by radioactive elements or produced by X-ray machines. The best term for atomic radiation is ionizing radiation, because sound waves, light waves, and radio waves are also kinds of radiation. Ionizing Alpha () Beta (b) Gamma () X-Rays Neutrons Non-Ionizing Radio waves Microwaves Infrared Ultraviolet Visible Light Radioactivity The throwing out of charged particles or gamma rays from the nucleus of the atom. Some elements are naturally radioactive, while others can be made radioactive by squeezing extra neutrons into the nucleus. Radon (Rn) A heavy radioactive gas given off by rocks containing radium (or thorium). Rn-222 is the main isotope. Rem A unit describing the intensity of radiation, the type of radiation, and the effect on the body. Sievert (Sv) The SI equivalent of the rem. One sievert is equal to 100 rem. X-ray Radiation produced inside a vacuum tube when highspeed electrons hit a metal target. When these rays pass through an object, they give a shadow picture of the denser portions. They must be used carefully because of their ability to ionize atoms in the body. Requirement #1 We Covered: ALARA Alpha Particle Atom Background Beta Particle Contamination Curie (Ci) Becquerel (Bq) Gamma Ray Half-life Ionization Quark Isotope Neutron Nuclear Energy Nuclear Reactor Particle Accelerator Rad Gray (Gy) Radiation Radioactivity Radon (Rn) Rem Sievert (Sv) X-Ray