Nuclear Physics

Nuclear Physics terms

1. Absorbed dose Energy imparted to a body by radiation, measured per unit mass (kg) of tissue.
2. Absorber The component of a solar thermal collector that absorbs solar radiation and converts it to heat, or, as in a solar photovoltaic device, the material that…
3. activity The number of transformations that take place each second in a given amount of radioactive material.
4. Alpha Particle A positively charged particle, indistinguishable from a helium atom nucleus and consisting of two protons and two neutrons.
5. Alpha particle (alpha radiation, alpha ray) A positively charged particle (a Helium-4 nucleus) made up of two neutrons and two protons.
6. alpha radiation Same as alpha particle.
7. Atom A particle of matter indivisible by chemical means. It is the fundamental building block of elements.
8. Atomic number The number assigned to each element on the basis of the number of protons found in the element's nucleus.
9. Atomic weight (atomic mass) Approximately the sum of the number of protons and neutrons found in the nucleus of an atom.
10. Background Radiation Filling all space, e.g. the radiation from the early, hot universe.
11. becquerel The special name for the unit that expresses a measure of activity. One becquerel corresponds to one disintegration per second of any radionuclide.
12. beta particle A high-speed electron or positron, emitted in radioactive decay.
13. Beta particle (beta radiation, beta ray) An electron of either positive charge (ß+) or negative charge (ß-), which has been emitted by an atomic nucleus or neutron in the process of a…
14. Contamination To make impure, infected, corrupt, etc, by contact with or addition of something; to pollute something.
15. COW A radioisotope generator system.
16. curie A unit of radioactivity, equal to the amount of a radioactive isotope that decays at the rate of 3.7 x 1010 disintegrations per second.
17. Curie (Ci) (Ci) The basic unit used to describe the intensity of radioactivity in a sample of material.
18. Daughter A nucleus formed by the radioactive decay of a different (parent) nuclide.
19. Decay (radioactive) The change of one radioactive nuclide into a different nuclide by the spontaneous emission of alpha, beta, or gamma rays, or by electron capture.
20. Decontamination The removal of radioactive contaminants by cleaning and washing with chemicals.
21. Density The average number of people, families, or housing units on one unit of land. Density is also expressed as dwelling units per acre.
22. dermal uptake The transfer of a contaminant from air, water, or soil into or through the outer skin layer; considered an exposure route in an exposure assessment.
23. developmental and reproductive effects Effects caused by some physical, chemical, or biological agent, such as radiation, to the formation and development of a fetus, that results in one or…
24. Displacement Displacement is the replacement of a U.S. worker by an H-1B worker in an essentially equivalent job and occurs within the period beginning 90 days before…
25. dissociation A chemical process by means of which a change in physical condition causes a molecule to split into simple groups of atoms, single atoms, or ions.
26. dose The amount of medicine taken, or radiation given, at one time.
27. dose assessment The process by which uptake and dose of a toxic substance are identified and quantified.
28. dose equivalent An absorbed dose that is adjusted or weighted to account for the potential of different radiations with the same damage.
29. Electromagnetic Radiation (ee-LEK-troh-mag-NEH-tik ray-dee-AY-shun) Low-energy radiation that comes from the interaction of electric and magnetic fields.
30. Electron A sub-atomic particle that has a negative electric charge.
31. Electron capture A radioactive decay process in which an orbital electron is captured by and merges with the nucleus.
32. Eluant Washing solution (The solution that is introduced into the cow).
33. Eluate The washings obtained by elution (the solution that comes out of the cow).
34. Elute To separate by washing (to milk).
35. Excitation The power required to energize the magnetic field of a generator.
36. Excited state The state of an atom or nucleus when it possesses more than its normal energy. The excess energy is usually released eventually as a gamma ray.
37. exposure Contact of an organism with a chemical, radiological, or physical agent.
38. exposure assessment The process by which contact with a toxic substance is identified and quantified.
39. Fission The splitting of heavier atomic nuclei into lighter ones. In the case of heavy atoms (e.g., uranium, plutonium), this will release energy.
40. Fission products Nuclei formed by the fission of heavy elements. They are of medium atomic weight and almost all are radioactive. Examples: strontium-90, cesium-137.
41. gamma radiation Electromagnetic radiation emitted by radioactive decay and having energies in a range from ten thousand (104) to ten million (107) electron volts.
42. Gamma Ray A type of high-energy radiation that is different from an x-ray.
43. Geiger counter A Geiger-Müller detector and measuring instrument. It contains a gas-filled tube which discharges electrically when ionizing radiation passes through it…
44. Generator A device for converting mechanical energy to electrical energy.
45. gray The special name for the unit that expresses a measure of absorbed dose. One gray corresponds to an energy deposition of one joule per kg of living tissue.
46. Half-life The time in which half the atoms of a particular radioactive nuclide disintegrate. The half-life is a characteristic property of each radioactive isotope.
47. Health physics That science devoted to recognition, evaluation, and control of all health hazards from ionizing radiation.
48. heritable genetic effects Genetic damage caused by an external agent such as radiation, which manifests itself in the gene carrier and is capable of being passed on to succeeding…
49. Induced Radioactivity Radioactivity that is created by bombarding a substance with neutrons in a reactor or with charged particles produced by particle accelerators.
50. ingestion Taking into the body by mouth.
51. inhalation In medicine, refers to the act of taking a substance into the body by breathing.
52. Ion An atom or molecule that has lost or gained one or more electrons and has become electrically charged as a result.
53. ionizing radiation (I-uh-NYZ-ing RAY-dee-AY-shun) A type of radiation made (or given off ) by x-ray procedures, radioactive substances, rays that enter the Earth's…
54. Irradiate Application of radiation from a source (heat, light, Xrays) to a structure or organism.
55. isomer One of two or more compounds that have the same chemical formula but different arrangements of the atoms within the molecules and that may have different…
56. Isometric transition A mode of radioactive decay where a nucleus goes from a higher to a lower energy state. The mass number and the atomic number are unchanged.
57. isotope (I-soh-tope) A form of a chemical element in which the atoms have the same number of protons (part of the nucleus of an atom) but with a different number…
58. K-capture The capture by an atom's nucleus of an orbital electron from the first K-shell surrounding the nucleus.
59. KEV One thousand electron volts.
60. MeV One million electron volts.
61. Microcurie (µCi) (µCi) One millionth of a curie (3.7 x 104 disintegrations per second).
62. Milk To elute a cow.
63. Minigenerator A trademark of Union Carbide Corporation that is used to identify radioisotope generator systems for educational use.
64. model See Exhibit.
65. monitor (MAH-nih-ter) In medicine, to regularly watch and check a person or condition to see if there is any change.
66. Neutrino A lepton with no electric charge. Neutrinos participate only in weak and gravitational interactions and are therefore very difficult to detect.
67. Neutron A baryon with electric charge zero; it has the basic structure of two down quarks and one up quark (held together by gluons).
68. Nuclear reactor A device in which a fission chain reaction can be initiated, maintained, and controlled.
69. Nucleon Proton or neutron, part of atomic nucleus.
70. Nucleonics The science, technology, and application of nuclear energy.
71. Nucleus (NOO-klee-us) In biology, the structure in a cell that contains the chromosomes.
72. Nuclide Any species of atom that exists for a measurable length of time. A nuclide can be distinguished by its atomic weight, atomic number, and energy state.
73. Parent A radionuclide that decays to another nuclide which may be either radioactive or stable.
74. Photon A photon is both a wave and a particle. A beam of light is composed of these particles.
75. Probability The chance that an event occurs. It is usually expressed as a percent. Zero percent denotes impossibility, while 100% denotes certainty.
76. Proton A small, positively charged particle of matter found in the atoms of all elements.
77. RAD Radiation Absorbed Dose. The basic unit of an absorbed dose of ionizing radiation.
78. Radiation (RAY-dee-AY-shun) Energy released in the form of particle or electromagnetic waves.
79. Radioactive dating A technique for estimating the age of an object by measuring the amounts of various radioisotopes in it.
80. Radioactive Waste Materials left over from making nuclear energy. Radioactive waste can living organisms if it is not stored safely.
81. Radioactivity The spontaneous decay of disintegration of an unstable atomic nucleus accompanied by the emission of radiation.
82. radioisotope (RAY-dee-oh-I-suh-tope) An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable.
83. Radionuclide (RAY-dee-oh-NOO-klide) An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable.
84. Rate meter An electronic instrument that indicates, on a meter, the number of radiation induced pulses per minute from radiation detectors such as a Geiger-Muller…
85. relative biological effectiveness (RBE) (RBE) An adjustment factor used to adjust an absorbed dose to account for its relative potential to do damage in biological tissue.
86. Risk The possibility of loss; the uncertainty of future returns.
87. risk assessment a scientifically based process consisting of the following steps: i) hazard identification; ii) hazard characterization; iii) exposure assessment; and iv)…
88. sampling The process of digitizing analog information to identify relevant information.
89. Scaler An electronic instrument for counting radiation induced pulses from radiation detectors such as a Geiger-Muller tube.
90. Scintillation counter An instrument that detects and measures gamma radiation by counting the light flashes (scintillations) induced by the radiation.
91. Secular equilibrium A state of parent-daughter equilibrium which is achieved when the half-life of the parent is much longer than the half-life of the daughter.
92. Shielding A protective barrier, usually a dense material, which reduces the passage of radiation from radioactive materials to the surroundings.
93. sievert (Sv) (Sv) A unit for expressing the equivalent magnitude of an absorbed dose which has been adjusted by a factor that expresses the relative tissue damage potential…
94. Source Any place or object from which air pollutants are released. Sources that are fixed in space are stationary sources and sources that move are mobile…
95. Spill The accidental release of radioactive materials.
96. Stable Non-radioactive.
97. tracer A substance (such as a radioisotope) used in imaging procedures.
98. transformation (TRANZ-for-MAY-shun) In medicine, the change that a normal cell undergoes as it becomes malignant.
99. Transmutation The transformation of one element into another by a nuclear reaction.
100. transport To move or be conveyed from one place to another. In the context of environmental contamination, a contaminant is transported from one location to another…