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71 Cards in this Set
- Front
- Back
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Nucleon |
A constituent particle of the atomic nucleus, either a neutron or proton |
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Nuclide |
A species of an atom characterized by the constitution of its nucleus |
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Isotope |
Nucleus which have the same number of protons but different number of neutrons any nucleus that have the same atomic number but different atomic mass numbers |
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Mass energy equivalence |
Mass and energy are interchangeable Mass May be transformed to energy and vice versa |
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Pair annihilation |
Two particles with mass specifically a positron and a electron collide and are transformed into two rays of electromagnetic energy |
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Mass defect |
The total mass of the atom is less than the sum of the masses of the individual proton and neutron |
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Binding energy |
The energy equivalent of mass defect |
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Binding energy per nucleon |
Binding energy divided by the total number of nucleons in the nucleus |
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Fission |
The splitting of the nucleus into at least two smaller nuclei with an accompanying release of energy |
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Criticality |
The condition in which the neutrons produced by fission are equal to the number of neutrons in a previous generation Neutrons in one generation go on to produce an equal number of fission event |
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Fusion |
The act of combining or fusing two or more atomic nuclei The process of fusing nuclei into a larger nucleus with an accompanying release of energy |
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4 sources of background radiation |
Terrestrial Internal emitters Cosmic Inhaled radionuclides |
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Origin, Radionuclides, variables an contribution to exposure of terrestrial radiation |
Found in soil and rock Uranium and thorium 18 mrem a year |
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Origin, Radionuclides, variables an contribution to exposure of cosmic radiation |
Primary Galactic Cosmic rays and secondary Solar Cosmic rays Decreases with latitude and increases with altitude 30mrem a year |
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Origin, Radionuclides, variables an contribution to exposure of internal emitters |
Intake and ingestion from the food chain K40, Rb87, Ra226, U238, Po210, and C14 30mrem a year |
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Origin, Radionuclides, variables an contribution to exposure of inhaled radionuclides |
Inhaled through air Radon and Thoron <1 mrem a year |
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The four artificially produced radiation |
Nuclear fallout Medical exposure Consumer products Nuclear facilities |
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Magnitude of dose received from Nuclear fall out |
Debris that settles to the earth as a result of nuclear blast <1 mrem a year |
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Magnitude of dose received from Medical exposures |
Diagnostic x-rays: Radiography, fluoroscopic, and photo fluoroscopic Medical radionuclides: nuclear medicine 300 mrem a year
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Magnitude of dose received from Consumer products |
Tv, microwaves, smoke-alarms, watches 12mrem year |
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Magnitude of dose received from Nuclear Facilities |
<1 mrem a year |
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Nuclear stability |
Governed by the particular combination and arrangement of neutrons and protons in a given nucleus |
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Three forces acting in the nucleus |
Gravitational electrostatic nuclear force |
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Gravitational |
Negligible attractive force between all nucleons Relatively long |
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Electrostatic |
Strong repulsive Force between like charged particles Relatively long |
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Nuclear force |
Strong attractive force between all nucleons extremely short |
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How is the neutron to proton ratio related to nuclear stability |
In a stable atom there is a balance between attractive and repulsive forces in the nucleus if the forces do not balance out that item cannot be stable |
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Radioactivity |
The property of certain nuclides of spontaneously Imitating energy from the nucleus in the form of particles and packets of electromagnetic waves |
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Radioactive decay |
The process by which a nucleus spontaneously disintegrates or is transformed by one or more discrete energy steps until a stable state is reached |
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Alpha decay |
Two protons and two neutrons 4 atomic mass units Electric charge of +2 |
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Beta minus decay |
A nuclide that has an excessive number of neutrons will usually decay by changing a neutron into a proton through an emission of negatively charged particle High neutron to proton ratio |
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Positron decay |
Low neutron to proton ratio |
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Electron capture |
Low neutron to proton ratio |
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Gamma |
Electromagnetic radiation it is energy photon |
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For unique aspects associated with the decay of radioactive nuclide |
Modes of decay types of a emission Energies of the mission involved rate of decay |
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Artificial radioactivity |
Man-made nuclear reactions Produce radionuclides generally revert to stability in only a few decay steps Activation and Fission products decay by Beta or positron a mission or by orbital electron capture |
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Why are fission products unstable |
The nuclear fragments directly resulting from fission invariably have too large a proportion of neutrons to protons for stability and consequently tend to achieve stability by beta minus emissions |
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The three natural occurring radioactive families and the products of each |
Uranium 238 series thorium 232 series uranium 235 actinium series Decay to lead |
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Curie |
That amount of radioactive material that will produce 3.7 e10 disintegrates per second |
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Becquerel |
Quantity of a radioactive material in which one atom is transformed per second or undergoes one disintegration per second |
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Specific activity |
The activity per Unit mass of a radioactive substance and is reported in units such as curies per gram CI/g or becquerels per kilogram BQ/KG |
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Half life |
The time that is required for the activity present to be reduced to 1/2 |
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Activity, time of decay and radiological half-life formula |
At=a0e(1/2)t/t1/2 |
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Exposure |
The measure of the ability of photons to produce ionization in the Air Roentegen |
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Absolute dose |
Units of those measure the amount of radiation energy absorbed or deposited per unit of mass |
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Equivalent dose |
Calculated as the absorbed dose multiplied by the quality factor which relates the relative risk from the type of radiation absorbed to the risk from the same dose of X or gamma radiation |
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Radiation weighting factor |
The modifying factor used to calculate the equivalent dose from average tissue or organ absorbed dose That absorb dose multiplied by the appropriate radiation weighting factor |
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Roentgen |
Exposure |
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Rad |
100 ergs of energy in one gram of any material |
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No equilibrium |
The half-life of the parent is shorter than that of the daughter that you never reach a state of equilibrium |
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When two or more light nuclei combine to form a large nucleus in fusion this changes the |
Binding wnergy |
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A neutron or proton in a nucleus may be called a |
Nucleon |
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The total binding energy of a nucleus divided by the total number of nucleons in the nucleus is the |
Binding energy per nucleon |
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The process in which two or more nuclei combine to form a larger nucleus is called |
Fusion |
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The binding energy per nucleon is average energy which must be added in order to remove |
A nucleon from a nucleus |
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The two elements who’s radionuclides are generally considered to be the greatest contributor of those equivalent from natural terrestrial background radiation sources are |
Uranium Thorium |
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The radionuclide generally considered to be the greatest contributor of dose from internal emitters as part of natural background radiation source is |
Potassium 40 |
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The average dose to the general population of the US from all combined medical exposures as part of man-made background radiation sources is approximately how many mrem a year |
53 |
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The factor which contributes the greatest variability in dose from natural terrestrial background radiation is |
Geology |
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When two or more light nuclei combine to form a large nucleus in fusion this changes the |
Binding energy |
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How many rems equal 1 Sievert |
100 rem |
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Each radionuclide has unique qualities of |
Rate of decay type and energy of decay |
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Which is an aspect associated with the radioactive decay of a specific radionuclide |
Modes of decay |
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Rem |
The quantity of ionizing radiation whose biological affect in man is equal to that produced by one roentgen of x-rays or gamma radiation the Dose equivalent in rem is numerically equal to that absorb those in rad multiplied by the quality factor Rem = radxQ |
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Sievert |
The SI the derived unit of dose equivalence equal to the absorbed dose in grays multiplied by the quality factor sievert= grayxQ 1Sv=100 rem |
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Parent |
The nucleus before the decay or transformation |
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Daughter |
The nucleus after the decay |
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Decay chain |
The various steps from parent to daughter that trace to stability a series of transmutations from parent to stable daughter |
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Equilibrium |
That amount of activity being produced is the same as amount that is decaying |
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Secular equilibrium |
The half-life of the parent is very much longer than a half life of the daughter the majority of the activity will be contributed by the parentAs more of the parent nuclear decay is the amount of activity contributed by the daughter will increase when in equilibrium the activity of the daughter is equal to the activity of the parents |
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Transient equilibrium |
The half-life of other parent is longer than that of the daughter but not very long in a freshly purified parent fraction the daughter activity build up then decays with the same rate of decay as the parent |
