0
No shielding material truly absorbs electromagnetic radiation, it attenuates it. The attenuation is by a certain amount for a certain standard thickness. The standard thickness is called the half thickness and is used to quantify shielding effectiveness for a given type of electromagnetic radiation. One half thickness attenuates the power of the given type of radiation by 50% or in decibel units -3dB. Thus the power of the radiation after a given number of half thicknesses of a given shield is:
- 50% or -3dB
- 25% or -6dB
- 12.5% or -9dB
- 6.25% or -12dB
- 3.125% or -15dB
- 1.5625% or -18dB
- 0.78125% or -21dB
- 0.390625% or -24dB
- 0.1953125% or -27dB
- 0.097655625 or -30dB
- etc.
As you can see no thickness of shield material can completely attenuate electromagnetic radiation to nothing, also the higher the frequency of electromagnetic radiation the longer the half thickness is so for x-rays and gamma rays it takes very large thicknesses to get any useful attenuation.
For particle radiation the situation is completely different, the radiation can sometimes be absorbed and sometimes can't:
- alpha particles are 100% absorbed by a single sheet of paper or the first layer of living tissue they encounter
- most beta particles are 100% absorbed by a single sheet of thin metal foil (e.g. aluminum foil)
- neutrons penetrate most matter as if it was not there, unless it contains certain elements (e.g. boron, cadmium, uranium) that have high neutron capture crosssections in which case the neutron flux is attenuated much like electromagnetic radiation as described above
- neutrinos penetrate all matter as if it was not there
- etc.
Wiki User
∙ 9y ago
Add your answer:
Earn +20 pts
What element used as shield for radioactivity?
It depends somewhat on the type of radiation that one needs to be shielded.Lead is very effective for gamma rays, however if the radiation is mostly neutron radiation then borated reinforced concrete is much more effective than lead (the hydrogen in the water of crystallization in the concrete slows the neutrons and the boron then absorbs the slow neutrons). Nuclear reactors which produce intense radiation of both gamma ray and neutron often use alternating layers of lead plate and borated reinforced concrete for shielding.If all you are shielding against is beta radiation then a sheet of aluminum foil is typically adequate.If all you are shielding against is alpha radiation then your skin (do not ingest or inhale alpha emitters) or one sheet of paper is adequate.
What type of radiation does radium give off?
Radium emits alpha, beta, and gamma radiation. Alpha radiation is fully ionized helium nuclei. Beta radiation is high energy electrons. Gamma radiation is very high energy electromagnetic radiation. All of these can do significant damage to living things.
What term is used to describe the collection that includes gamma rays x-rays ultraviolet light visible light infrared radiation and radio waves?
All travel at the same speed through a vacuum
What is the common property of all electromagnetic radiation?
They all behave like a wave (which can be caracterized by frequency and wave lenght)
Who was lead singer of the byrds?
there was no lead singer....all members of the group shared vocals.
How does a radioactive film badge protect workers?
It absorbs all of the radiation that is near
Would the thermometer wrapped with a black cloth have a higher reading than one not wrapped?
Color is determined by the amount of radiation an object absorbs/reflects. Black absorbs all colors of light, meaning it absorbs the most radiation, increasing heat.
Does black absorb or reflect?
Black absorbs radiation. A perfectly black body would absorb all the radiation that is incident upon it.
What material can completely block radition produced when mercury is spun?
Lead can block radiation of all types. This is why lead aprons are worn whenever anyone is undergoing any kind of x-ray procedure. The lead apron protects from the radiation that is generated by the x-ray machine.
What is the purpose of the lead apron and how does it work?
Technicians (and patients) who are exposed to ionizing radiation (most commonly, x-rays) wear lead aprons to protect their vital organs from radiation. Repeated or prolonged exposure to ionizing radiation has been shown to cause cancer. Lead absorbs x-rays, alpha particles and beta particles. It is much less effective at absorbing gamma rays, but it's far better than no protection at all.
Why cant all the wavelengths enter the earth's atmosphere?
The atmosphere absorbs the electromagnetic solar radiation.
What is an absorption nebula?
An absorption nebula is a dark nebula, which absorbs all incident radiation without reemission.
What is a perfect black body?
A perfect blackbody absorbs all radiation incident on it and It emits electromagnetic radiation in the form of thermal radiation from its surface. OR A perfect blackbody is a perfect emitter and perfect absorber.
How much radiation does the sun produce?
44888000900 kg of radiation gas, obviously slowly killing itself.
What is the greenhouse gas that absorbs the sun's incoming shortwave radiation?
No greenhouse gas absorbs the sun's incoming shortwave radiation. All the greenhouse gases (carbon dioxide, methane, water vapor, nitrous oxide, CFCs etc) absorb the outgoing longwave infrared radiation from the warmed surface of the earth.
What is a black body?
A black body is a theoretical body in physics, which absorbs all incident electromagnetic radiation and reflects none.
What products can you use little of and still block radiation?
It depends on what kind of radiation... Alpha radiation can be stopped with a sheet of paper or a few inches of air. Beta radiation can be stopped with a thin sheet of metal. Neutron radiation, depending on energy, requires large thicknesses of lead or concrete. Gamma radiation, depending on energy, also requires large thicknesses of lead or concrete. Some of the higher energy gammas, such as cosmic rays, can be quite difficult to stop at all.
