Aralık 30th, 2009 | 
Author: Energetic Quanta: Gamma-Rays
Gamma rays…
- Are emitted from the nucleus to trim excess energy.
- Tend to carry higher energies than X-rays, but this does not have to be the case
For example, after a larger energy decay particle (e.g. a beta particle) is emitted, the nucleus may still be slightly unstable (i.e., the atom remains in an isomeric or excited state). Emission of a gamma ray provides a means to lose a smaller amount of excess energy.
Important examples of gamma emitters: potassium-40, cobalt-60, cesium-137, and technetium-99m
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| Simplified electromagnetic spectrum with relative wavelength scale. Photons in the spectrum of visible light are energized at 2 to 3 eV. Contrast this with the energies carried by X-rays and gamma rays – ranging from thousands to millions of electron-volts. |
Category: medicine, radiation biology, radiology | 
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No Comments »Energetic Quanta: X-rays & Gamma-Rays
Gamma rays and X-rays are types of photons…
- That represent pure electromagnetic energy
- That progress at the speed of light
- That may pass through all human tissues unimpeded and unchanged
- Having no mass or charge, are neither attracted to nor repulsed by charged particles
- Gamma-rays originate from the nucleus
- X-rays originate from electron clouds
Category: medicine, radiation biology, radiology | Tags: &, *, all, and, are, at, attracted, by, charge, charged, clouds, electromagnetic, electron, energetic, Energetic Quanta: X-rays & Gamma-Rays, energy, from, Gamma-rays, Gamma-Rays Gamma, Having, human, light, mass., may, neither, no, nor, nucleus, of, or, originate, particles, pass, photons…, progress, pure, quanta., rays, represent, repulsed, speed, that, the, through, tissues., to, types, unchanged, unimpeded, X-rays | No Comments »Energetic Quanta: Beta Particles
Beta Particles…
- Are smaller (1/2000 the size of proton) and less energetic than alpha particles
- Have negative charge
- Are created when a neutron transmutates into a proton
- Are emitted during decay of iodine-131, phosphorus-32, carbon-14, and strontium-90
Category: medicine, radiation biology, radiology | Tags: (1/2000, (proton, *, a, Alpha, and, are, Beta, carbon-14, charge, created, Decay, during, emitted, energetic, Energetic Quanta: Beta Particles, have, into, iodine-131, less, negative, neutron, of, particles, Particles Beta, particles…, phosphorus-32, quanta., size, smaller, strontium-90, than, the, transmutates, When | No Comments »Energetic Quanta: Neutrons
Neutrons…
- Are uncharged particles
- May carry significant kinetic energy (”Fast Neutrons”)
- May collide with a nuclear proton, causing its ejection (”Recoil Protons”)
- Produce biologically-important ionizations and excitations via such energetic recoil protons
- Are often produced as part of fission reactions
Category: medicine, radiation biology, radiology | Tags: ("Fast, ("Recoil, (proton, *, a, and, are, as, biologically-important, carry, causing, collide, ejection, energetic, Energetic Quanta: Neutrons, energy, excitations, fission, ionizations, its, kinetic, may, Neutrons Neutrons…, neutrons)., nuclear, of, often, part, particles, produce, produced, protons, quanta., reactions, significant, such, uncharged, via, with | No Comments »Energetic Quanta: Alpha Particles
Alpha particles…
- Are large and positively charged
- Tend to cause ionizations and lose energy over a very short distance
- Are composed of two protons and two neutrons (i.e. a naked helium nucleus)
- Large size + relatively high charge prevent deep penetration of matter (blocked by dead skin or paper)
- Chronic exposure to inhaled alpha particles is a lung cancer risk
- Are important in the uranium decay series, of which radon is a product
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