Difference between revisions of "Radiation"

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Natural '''Radiation''' on [[Mars]] is much higher compared with [[Earth]]. The thin [[atmosphere]] provides only a small shielding effect against harmful [[solar radiation]] and [[cosmic radiation]].  Mars also lacks the [[magnetosphere]] that protects Earth.
 
Natural '''Radiation''' on [[Mars]] is much higher compared with [[Earth]]. The thin [[atmosphere]] provides only a small shielding effect against harmful [[solar radiation]] and [[cosmic radiation]].  Mars also lacks the [[magnetosphere]] that protects Earth.
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 +
==Types of Radiation==
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Radiation comes in a variety of forms:<ref>http://www.nas.nasa.gov/About/Education/SpaceSettlement/designer/needs.html#SHIELDING</ref>
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{| border=1
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|-
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!Name
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!Relative Biological<br/> Effectiveness RBE
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!Source
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|-
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|'''[[X-ray|X-Rays]] and [[gamma ray|Gamma Rays]]'''
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|1
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|[[Radiation belts]], [[solar radiation]], and bremsstrahlung electrons
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|-
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|'''[[electron|Electrons]]'''<br/> 
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1.0 MeV<br/>
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0.1 MeV
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|<br/>
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1<br/>
 +
1.08
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|Radiation belts
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|-
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|'''[[proton|Protons]]'''<br/> 
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100 MeV<br/>
 +
1.5 MeV<br/> 
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0.1 MeV
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|<br/>
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1-2<br/> 
 +
8.5<br/> 
 +
10
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|Cosmic rays, inner-radiation belts, and solar [[cosmic rays]]
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|-
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|'''[[neutron|Neutrons]]'''<br/> 
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0.05 ev (thermal)<br/> 
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1.0 MeV<br/> 
 +
10 MeV
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|<br/>
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2.8<br/> 
 +
10.5<br/> 
 +
6.4
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|Nuclear interactions in the [[sun]]
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|-
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|'''[[alpha particles|Alpha Particles]]'''<br/> 
 +
5.0 MeV<br/> 
 +
1.0 MeV<br/> 
 +
Heavy Primaries
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|<br/>
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15<br/> 
 +
20<br/> 
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varies widely
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|Cosmic rays
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|}
  
 
==Danger==
 
==Danger==
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*What are the legal limits for radiation exposure for some professional activities?
 
*What are the legal limits for radiation exposure for some professional activities?
 
*Does regolith emit an own portion of radiation, some kind of secondary radiation due to the long exposure to cosmic and solar radiation?
 
*Does regolith emit an own portion of radiation, some kind of secondary radiation due to the long exposure to cosmic and solar radiation?
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 +
==References==
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<references/>
  
 
==External links==
 
==External links==

Revision as of 19:10, 18 January 2009

Natural Radiation on Mars is much higher compared with Earth. The thin atmosphere provides only a small shielding effect against harmful solar radiation and cosmic radiation. Mars also lacks the magnetosphere that protects Earth.

Types of Radiation

Radiation comes in a variety of forms:[1]

Name Relative Biological
Effectiveness RBE
Source
X-Rays and Gamma Rays 1 Radiation belts, solar radiation, and bremsstrahlung electrons
Electrons

1.0 MeV
0.1 MeV


1
1.08

Radiation belts
Protons

100 MeV
1.5 MeV
0.1 MeV


1-2
8.5
10

Cosmic rays, inner-radiation belts, and solar cosmic rays
Neutrons

0.05 ev (thermal)
1.0 MeV
10 MeV


2.8
10.5
6.4

Nuclear interactions in the sun
Alpha Particles

5.0 MeV
1.0 MeV
Heavy Primaries


15
20
varies widely

Cosmic rays

Danger

Exposure to dangerous levels of radiation causes radiation sickness and cancer. Any exposure to radiation, no matter how slight, poses some risk. Small dose - small risk of cancer. High dose - high risk of cancer.

Nevertheless, there are defined legal limits for exposure during work for several professional activities, such as for X-ray assistants, airplane personnel, etc.

Effect on material

Radiation can change the properties of plastics and metals, making them brittle after a period of time.

Protection

Houses should be equipped with a shielding, thick enough to reduce the radiation to a level equal to Earth, that is, almost zero. Best protection may be achieved with houses built in natural caves or set into cliffs or hillsides.

Space suits must be designed with radiation in mind. The suit should provide adequate shielding for the occupant. It may be necessary to design suits with several grades of protection. Suits designed for short-term use can carry lighter shielding which would reduce weight and improve maneuverability.

During severe radiation events, such as solar flares, surface settlements may use storm shelters with heavier than normal shielding.

Open issues

  • How much higher is the UV and cosmic radiation?
  • What is the required thickness of a regolith or water layer upon a house for radiation shielding?
  • What are the legal limits for radiation exposure for some professional activities?
  • Does regolith emit an own portion of radiation, some kind of secondary radiation due to the long exposure to cosmic and solar radiation?

References

External links