Heavy Ions - Revision history

RichardWSmith: /* Shielding Considerations */ Fixed link.

2024-08-24T06:10:36Z

Shielding Considerations: Fixed link.

← Older revision		Revision as of 07:10, 24 August 2024
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	See [[Cosmic Radiation]] for a detailed discussion of this. Briefly, heavy ions with high energies break into secondary radiation when they hit air or other matter (say the walls of the habitat). This happens all the time on Earth, such particles flow thru you all your life. Settlers living on Mars will accept a higher radiation dose, but will want to spend most of their time with a couple meters of soil, or 4 meters of water as shielding.		See [[Cosmic Radiation]] for a detailed discussion of this. Briefly, heavy ions with high energies break into secondary radiation when they hit air or other matter (say the walls of the habitat). This happens all the time on Earth, such particles flow thru you all your life. Settlers living on Mars will accept a higher radiation dose, but will want to spend most of their time with a couple meters of soil, or 4 meters of water as shielding.

	Alternately, if they live in a [[Lava ~~Tube~~]] they would have a lower radiation dose from cosmic rays than people living on Earth.		Alternately, if they live in a [[Lava tube]] they would have a lower radiation dose from cosmic rays than people living on Earth.

	==References==		==References==
	<references />		<references />

RichardWSmith: The conclusion that heavy ions will require all settlements to have shielding BETTER than a solar storm shelter is wrong. Rewrote this paragraph.

2024-08-24T06:09:46Z

The conclusion that heavy ions will require all settlements to have shielding BETTER than a solar storm shelter is wrong. Rewrote this paragraph.

← Older revision		Revision as of 07:09, 24 August 2024
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	==Shielding Considerations==		==Shielding Considerations==
	~~Heavy~~ ions ~~generate~~ secondary radiation ~~due to~~ the ~~very high energy~~ of the ~~particles~~. This ~~means~~ the ~~thickness of~~ radiation ~~shielding needs~~ to ~~be increased over the requirements~~ of ~~solar storm shelters. This is particularly~~ a ~~consideration for long term settlements~~, ~~where the accumulation~~ of radiation ~~damage~~ from ~~inadequate shielding might lead to increased cancer rates, neurological, and tissue damage over time~~.		See [[Cosmic Radiation]] for a detailed discussion of this. Briefly, heavy ions with high energies break into secondary radiation when they hit air or other matter (say the walls of the habitat). This happens all the time on Earth, such particles flow thru you all your life. Settlers living on Mars will accept a higher radiation dose, but will want to spend most of their time with a couple meters of soil, or 4 meters of water as shielding.

			Alternately, if they live in a [[Lava Tube]] they would have a lower radiation dose from cosmic rays than people living on Earth.

	==References==		==References==
	<references />		<references />

JimL: Tried to improve explanation of RBE.

2020-01-08T20:42:47Z

Tried to improve explanation of RBE.

← Older revision		Revision as of 21:42, 8 January 2020
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	[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]		[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]

	The effects of high doses of x-rays and gamma rays have been studied thoroughly by analyzing the health of exposed groups.<ref name=":1" /> However, in the case of alpha particles and especially heavy ion radiation, exposures on earth are very rare, and estimates of the risk to astronauts are derived solely from animal model and cell culture studies and application of biophysics principles.<ref name=":0" />		The effects of high doses of x-rays and gamma rays have been studied thoroughly by analyzing the health of exposed groups.<ref name=":1">Goodhead DT. (2018, Jun 8). Track Structure and the Quality Factor for Space Radiation Cancer Risk. <nowiki>https://ntrs.nasa.gov/search.jsp?R=20180006105</nowiki></ref> However, in the case of alpha particles and especially heavy ion radiation, exposures on earth are very rare, and estimates of the risk to astronauts are derived solely from animal model and cell culture studies and application of biophysics principles.<ref name=":0" />

	Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" />		Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" />

	Linear energy transfer (LET) is a measure of the amount of energy deposited in tissue per unit length of a particle's trajectory.<ref>Wagenaar JD. (1995, Oct 6). Linear Energy Transfer. In ''Radiation Physics Principles'' (Section 7.2.3). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.2/7_2.3.html</nowiki></ref> LET increases as a function of ion charge, and decreases as a function of velocity.<ref>Wagenaar JD. (1995, Oct 6). Stopping Power. In Radiation Physics Principles (Section 7.1.2). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.1/7_1.2.html</nowiki></ref> Experimental irradiation of mouse cell cultures has indicated that heavy ions with an LET greater than 10 keV/μm are more likely to cause irreparable cell damage, compared to protons or alpha particles.<ref>Wilson JW, Cucinotta FA, Thibeault SA, Kim M-H, Shinn JL, & Badavi FF. (1997, Dec). In JW Wilson, J Miller, A Konradi, & FA Cucinotta, (Eds.), ''Shielding Strategies for Human Space Exploration'' (pp. 109-149). NASA Conference Publication 3360. <nowiki>http://hdl.handle.net/2060/19980137598</nowiki></ref>		Linear energy transfer (LET) is a measure of the amount of energy deposited in tissue per unit length of a particle's trajectory.<ref>Wagenaar JD. (1995, Oct 6). Linear Energy Transfer. In ''Radiation Physics Principles'' (Section 7.2.3). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.2/7_2.3.html</nowiki></ref> LET increases as a function of ion charge, and decreases as a function of velocity.<ref>Wagenaar JD. (1995, Oct 6). Stopping Power. In Radiation Physics Principles (Section 7.1.2). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.1/7_1.2.html</nowiki></ref> Experimental irradiation of mouse cell cultures has indicated that heavy ions with an LET greater than 10 keV/μm are more likely to cause irreparable cell damage, compared to protons or alpha particles.<ref>Wilson JW, Cucinotta FA, Thibeault SA, Kim M-H, Shinn JL, & Badavi FF. (1997, Dec). In JW Wilson, J Miller, A Konradi, & FA Cucinotta, (Eds.), ''Shielding Strategies for Human Space Exploration'' (pp. 109-149). NASA Conference Publication 3360. <nowiki>http://hdl.handle.net/2060/19980137598</nowiki></ref>

	~~LET has historically been used to estimate relative~~ biological effectiveness (RBE)~~, which~~ is a ~~measure of~~ how harmful radiation is, as compared to the same dose of ~~X-rays or~~ gamma rays. ~~While this estimate might work well~~ for ~~alpha particles (~~the ~~most common type of high-~~LET ~~radiation encountered~~ on ~~earth), it might not accurately characterize~~ the ~~damage done by heavy ions~~. The LET of [[cosmic radiation]] ranges up to around 5,000 KeV/um. RBE ~~is considered~~ to ~~peak at around 100 KeV/um; above~~ that ~~it decreases on account of the smaller number of particles per dose~~. NASA has ~~adopted a new version of the mathematical formula used to~~ estimate ~~RBE (called~~ the "NASA quality factor"), which is designed to ~~produce more accurate estimates~~ for heavy ~~ions~~.<ref name=":1"~~>Goodhead DT. (2018, Jun 8). Track Structure and the Quality Factor for Space Radiation Cancer Risk. <nowiki>https:~~/~~/ntrs.nasa.gov/search.jsp?R=20180006105</nowiki></ref~~>		=== Relative Biological Effectiveness ===
			Relative biological effectiveness (RBE) is a number that indicates how harmful a type of radiation is, compared to the same dose of gamma rays.

			The RBE of heavy ion radiation is not fully understood. RBE for heavy ions appears to increase with LET, up to around 100-200 KeV/um. For LET levels above 100-200 KeV/um, the relationship between LET and RBE depends on the effect studied. If cell mutation or death is measured, RBE peaks at a factor of 2 to 3, and actually decreases as LET increases above 200 KeV/um. However, one study of tumor formation found that RBE peaked at a factor of 30, and plateaued as LET increased beyond 200 KeV/um.<ref>National Research Council 1996. Radiation Hazards to Crews of Interplanetary Missions: Biological Issues and Research Strategies. Washington, DC: The National Academies Press. <nowiki>https://doi.org/10.17226/5540</nowiki>.</ref> The LET of cosmic radiation ranges up to around 5,000 KeV/um, so it is important to accurately estimate RBE values up to that level.

			NASA has developed an RBE estimate, the "NASA quality factor," which is based on a revised math formula that is designed to better account for the properties of heavy ion radiation that are normally ignored because they are not relevant on the Earth's surface.<ref name=":1" />

	==Shielding Considerations==		==Shielding Considerations==

JimL at 16:44, 2 September 2019

2019-09-02T16:44:30Z

← Older revision		Revision as of 17:44, 2 September 2019
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	==Exposures==		==Exposures==
	[[File:Heavy ions in GCR.png\|thumb\|<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>Abundances and energies of heavy ions in cosmic radiation.\|470x470px\|alt=]]The left-hand graph shows which elements make up the heavy ions in cosmic radiation. The right-hand graph shows the distribution of energy levels for 4 ions. For example, carbon is one of the more abundant ions in cosmic radiation, and the most likely kinetic energy level for a carbon ion falls between 100 and 1000 MeV.		[[File:Heavy ions in GCR.png\|thumb\|<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>Abundances and energies of heavy ions in cosmic radiation.\|470x470px\|alt=]]The left-hand graph shows which elements make up the heavy ions in cosmic radiation. The right-hand graph shows the distribution of energy levels for 4 ions. For example, carbon is one of the more abundant ions in cosmic radiation, and the most likely kinetic energy level for a carbon ion falls between 100 and 1000 MeV.
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	==Health Effects==		==Health Effects==

JimL at 16:43, 2 September 2019

2019-09-02T16:43:13Z

← Older revision		Revision as of 17:43, 2 September 2019
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	==Exposures==		==Exposures==
	[[File:Heavy ions in GCR.png\|thumb\|<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>Abundances and energies of heavy ions in cosmic radiation.\|~~none~~\|~~470x470px~~]]		[[File:Heavy ions in GCR.png\|thumb\|<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>Abundances and energies of heavy ions in cosmic radiation.\|470x470px\|alt=]]The left-hand graph shows which elements make up the heavy ions in cosmic radiation. The right-hand graph shows the distribution of energy levels for 4 ions. For example, carbon is one of the more abundant ions in cosmic radiation, and the most likely kinetic energy level for a carbon ion falls between 100 and 1000 MeV.

	==Health Effects==		==Health Effects==
	[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]		[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]

	The effects of high doses of x-rays and gamma rays have been studied thoroughly by analyzing the health of exposed groups.<ref name=":1" /> However, in the case of alpha particles and especially heavy ion radiation, exposures on earth are very rare, and estimates of the risk to astronauts are derived solely from animal model studies and application of biophysics principles.<ref name=":0" />		The effects of high doses of x-rays and gamma rays have been studied thoroughly by analyzing the health of exposed groups.<ref name=":1" /> However, in the case of alpha particles and especially heavy ion radiation, exposures on earth are very rare, and estimates of the risk to astronauts are derived solely from animal model and cell culture studies and application of biophysics principles.<ref name=":0" />

	Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" />		Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" />

JimL at 21:48, 26 August 2019

2019-08-26T21:48:47Z

← Older revision		Revision as of 22:48, 26 August 2019
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	Heavy ions are charged particles heavier than alpha particles.<ref>Heavy ion. (1998, Jul 20). In ''Encyclopaedia Britannica. <nowiki>https://www.britannica.com/science/heavy-ion</nowiki>''</ref> They constitute 1% of cosmic radiation.<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>		Heavy ions are charged particles heavier than alpha particles.<ref>Heavy ion. (1998, Jul 20). In ''Encyclopaedia Britannica. <nowiki>https://www.britannica.com/science/heavy-ion</nowiki>''</ref> They constitute 1% of [[cosmic radiation]].<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>


	==Exposures==		==Exposures==
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	Linear energy transfer (LET) is a measure of the amount of energy deposited in tissue per unit length of a particle's trajectory.<ref>Wagenaar JD. (1995, Oct 6). Linear Energy Transfer. In ''Radiation Physics Principles'' (Section 7.2.3). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.2/7_2.3.html</nowiki></ref> LET increases as a function of ion charge, and decreases as a function of velocity.<ref>Wagenaar JD. (1995, Oct 6). Stopping Power. In Radiation Physics Principles (Section 7.1.2). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.1/7_1.2.html</nowiki></ref> Experimental irradiation of mouse cell cultures has indicated that heavy ions with an LET greater than 10 keV/μm are more likely to cause irreparable cell damage, compared to protons or alpha particles.<ref>Wilson JW, Cucinotta FA, Thibeault SA, Kim M-H, Shinn JL, & Badavi FF. (1997, Dec). In JW Wilson, J Miller, A Konradi, & FA Cucinotta, (Eds.), ''Shielding Strategies for Human Space Exploration'' (pp. 109-149). NASA Conference Publication 3360. <nowiki>http://hdl.handle.net/2060/19980137598</nowiki></ref>		Linear energy transfer (LET) is a measure of the amount of energy deposited in tissue per unit length of a particle's trajectory.<ref>Wagenaar JD. (1995, Oct 6). Linear Energy Transfer. In ''Radiation Physics Principles'' (Section 7.2.3). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.2/7_2.3.html</nowiki></ref> LET increases as a function of ion charge, and decreases as a function of velocity.<ref>Wagenaar JD. (1995, Oct 6). Stopping Power. In Radiation Physics Principles (Section 7.1.2). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.1/7_1.2.html</nowiki></ref> Experimental irradiation of mouse cell cultures has indicated that heavy ions with an LET greater than 10 keV/μm are more likely to cause irreparable cell damage, compared to protons or alpha particles.<ref>Wilson JW, Cucinotta FA, Thibeault SA, Kim M-H, Shinn JL, & Badavi FF. (1997, Dec). In JW Wilson, J Miller, A Konradi, & FA Cucinotta, (Eds.), ''Shielding Strategies for Human Space Exploration'' (pp. 109-149). NASA Conference Publication 3360. <nowiki>http://hdl.handle.net/2060/19980137598</nowiki></ref>

	LET has historically been used to estimate relative biological effectiveness (RBE), which is a measure of how harmful radiation is, as compared to the same dose of X-rays or gamma rays. The LET of ~~GCR~~ ranges up to around 5,000 KeV/um. RBE is considered to peak at around 100 KeV/um; above that it decreases on account of the smaller number of particles per dose. ~~While this~~ estimate ~~might work well for alpha particles~~ (the ~~most common type of high-LET radiation encountered on earth~~), ~~it might not accurately characterize the damage done by~~ heavy ions ~~with the same LET~~.<ref name=":1">Goodhead DT. (2018, Jun 8). Track Structure and the Quality Factor for Space Radiation Cancer Risk. <nowiki>https://ntrs.nasa.gov/search.jsp?R=20180006105</nowiki></ref>		LET has historically been used to estimate relative biological effectiveness (RBE), which is a measure of how harmful radiation is, as compared to the same dose of X-rays or gamma rays. While this estimate might work well for alpha particles (the most common type of high-LET radiation encountered on earth), it might not accurately characterize the damage done by heavy ions. The LET of [[cosmic radiation]] ranges up to around 5,000 KeV/um. RBE is considered to peak at around 100 KeV/um; above that it decreases on account of the smaller number of particles per dose. NASA has adopted a new version of the mathematical formula used to estimate RBE (called the "NASA quality factor"), which is designed to produce more accurate estimates for heavy ions.<ref name=":1">Goodhead DT. (2018, Jun 8). Track Structure and the Quality Factor for Space Radiation Cancer Risk. <nowiki>https://ntrs.nasa.gov/search.jsp?R=20180006105</nowiki></ref>

	==Shielding Considerations==		==Shielding Considerations==

JimL: Improved the explanation of linear energy transfer.

2019-06-30T16:40:33Z

Improved the explanation of linear energy transfer.

← Older revision		Revision as of 17:40, 30 June 2019
Line 4:		Line 4:
	==Exposures==		==Exposures==
	[[File:Heavy ions in GCR.png\|thumb\|<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>Abundances and energies of heavy ions in cosmic radiation.\|none\|470x470px]]		[[File:Heavy ions in GCR.png\|thumb\|<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>Abundances and energies of heavy ions in cosmic radiation.\|none\|470x470px]]


	==Health Effects==		==Health Effects==
	[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]		[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]

	Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" /> Linear energy transfer (LET) is a measure of the amount of energy deposited in tissue per unit length of a particle's trajectory.<ref>Wagenaar JD. (1995, Oct 6). Linear Energy Transfer. In ''Radiation Physics Principles'' (Section 7.2.3). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.2/7_2.3.html</nowiki></ref> LET increases as a function of ion charge ~~and mass~~, and decreases as a function of velocity.<ref>Wagenaar JD. (1995, Oct 6). Stopping Power. In Radiation Physics Principles (Section 7.1.2). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.1/7_1.2.html</nowiki></ref> Experimental irradiation of mouse cell cultures has indicated that heavy ions with an LET greater than 10 keV/μm are more likely to cause irreparable cell damage, compared to protons or alpha particles.<ref>Wilson JW, Cucinotta FA, Thibeault SA, Kim M-H, Shinn JL, & Badavi FF. (1997, Dec). In JW Wilson, J Miller, A Konradi, & FA Cucinotta, (Eds.), ''Shielding Strategies for Human Space Exploration'' (pp. 109-149). NASA Conference Publication 3360. <nowiki>http://hdl.handle.net/2060/19980137598</nowiki></ref> LET has historically been used to estimate relative biological effectiveness of radiation, but this figure alone might not accurately characterize the damage done by heavy ions.<ref>Goodhead DT. (2018, Jun 8). Track Structure and the Quality Factor for Space Radiation Cancer Risk. <nowiki>https://ntrs.nasa.gov/search.jsp?R=20180006105</nowiki></ref>		The effects of high doses of x-rays and gamma rays have been studied thoroughly by analyzing the health of exposed groups.<ref name=":1" /> However, in the case of alpha particles and especially heavy ion radiation, exposures on earth are very rare, and estimates of the risk to astronauts are derived solely from animal model studies and application of biophysics principles.<ref name=":0" />

			Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" />

			Linear energy transfer (LET) is a measure of the amount of energy deposited in tissue per unit length of a particle's trajectory.<ref>Wagenaar JD. (1995, Oct 6). Linear Energy Transfer. In ''Radiation Physics Principles'' (Section 7.2.3). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.2/7_2.3.html</nowiki></ref> LET increases as a function of ion charge, and decreases as a function of velocity.<ref>Wagenaar JD. (1995, Oct 6). Stopping Power. In Radiation Physics Principles (Section 7.1.2). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.1/7_1.2.html</nowiki></ref> Experimental irradiation of mouse cell cultures has indicated that heavy ions with an LET greater than 10 keV/μm are more likely to cause irreparable cell damage, compared to protons or alpha particles.<ref>Wilson JW, Cucinotta FA, Thibeault SA, Kim M-H, Shinn JL, & Badavi FF. (1997, Dec). In JW Wilson, J Miller, A Konradi, & FA Cucinotta, (Eds.), ''Shielding Strategies for Human Space Exploration'' (pp. 109-149). NASA Conference Publication 3360. <nowiki>http://hdl.handle.net/2060/19980137598</nowiki></ref>

	~~The health effects of high doses of other types~~ of radiation ~~have been studied by analyzing~~ the ~~health of exposed groups (for example, survivors~~ of ~~nuclear weapon attacks~~ or ~~nuclear power plant accidents)~~. ~~However, in the case~~ of ~~heavy ion radiation~~, ~~estimates~~ of the ~~risk to astronauts are derived solely from animal model studies and application~~ of ~~biophysics principles~~. ~~As a result~~, ~~these estimates are less certain~~.<ref name=":0" />		LET has historically been used to estimate relative biological effectiveness (RBE), which is a measure of how harmful radiation is, as compared to the same dose of X-rays or gamma rays. The LET of GCR ranges up to around 5,000 KeV/um. RBE is considered to peak at around 100 KeV/um; above that it decreases on account of the smaller number of particles per dose. While this estimate might work well for alpha particles (the most common type of high-LET radiation encountered on earth), it might not accurately characterize the damage done by heavy ions with the same LET.<ref name=":1">Goodhead DT. (2018, Jun 8). Track Structure and the Quality Factor for Space Radiation Cancer Risk. <nowiki>https://ntrs.nasa.gov/search.jsp?R=20180006105</nowiki></ref>

	==Shielding Considerations==		==Shielding Considerations==

JimL at 19:01, 2 June 2019

2019-06-02T19:01:40Z

← Older revision		Revision as of 20:01, 2 June 2019
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	[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]		[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]

	Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" /> Linear energy transfer (LET) is a measure of the amount of energy deposited in tissue per unit length of a particle's trajectory.<ref>Wagenaar JD. (1995, Oct 6). Linear Energy Transfer. In ''Radiation Physics Principles'' (Section 7.2.3). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.2/7_2.3.html</nowiki></ref> LET increases as a function of ion charge and mass, and decreases as a function of velocity.<ref>Wagenaar JD. (1995, Oct 6). Stopping Power. In Radiation Physics Principles (Section 7.1.2). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.1/7_1.2.html</nowiki></ref> Experimental irradiation of mouse cell cultures has indicated that heavy ions with an LET greater than 10 keV/μm are more likely to cause irreparable cell damage, compared to protons or alpha particles.<ref>Wilson JW, Cucinotta FA, Thibeault SA, Kim M-H, Shinn JL, & Badavi FF. (1997, Dec). In JW Wilson, J Miller, A Konradi, & FA Cucinotta, (Eds.), ''Shielding Strategies for Human Space Exploration'' (pp. 109-149). NASA Conference Publication 3360. <nowiki>http://hdl.handle.net/2060/19980137598</nowiki></ref>		Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" /> Linear energy transfer (LET) is a measure of the amount of energy deposited in tissue per unit length of a particle's trajectory.<ref>Wagenaar JD. (1995, Oct 6). Linear Energy Transfer. In ''Radiation Physics Principles'' (Section 7.2.3). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.2/7_2.3.html</nowiki></ref> LET increases as a function of ion charge and mass, and decreases as a function of velocity.<ref>Wagenaar JD. (1995, Oct 6). Stopping Power. In Radiation Physics Principles (Section 7.1.2). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.1/7_1.2.html</nowiki></ref> Experimental irradiation of mouse cell cultures has indicated that heavy ions with an LET greater than 10 keV/μm are more likely to cause irreparable cell damage, compared to protons or alpha particles.<ref>Wilson JW, Cucinotta FA, Thibeault SA, Kim M-H, Shinn JL, & Badavi FF. (1997, Dec). In JW Wilson, J Miller, A Konradi, & FA Cucinotta, (Eds.), ''Shielding Strategies for Human Space Exploration'' (pp. 109-149). NASA Conference Publication 3360. <nowiki>http://hdl.handle.net/2060/19980137598</nowiki></ref> LET has historically been used to estimate relative biological effectiveness of radiation, but this figure alone might not accurately characterize the damage done by heavy ions.<ref>Goodhead DT. (2018, Jun 8). Track Structure and the Quality Factor for Space Radiation Cancer Risk. <nowiki>https://ntrs.nasa.gov/search.jsp?R=20180006105</nowiki></ref>

	The health effects of high doses of other types of radiation have been studied by analyzing the health of exposed groups (for example, survivors of nuclear weapon attacks or nuclear power plant accidents). However, in the case of heavy ion radiation, estimates of the risk to astronauts are derived solely from animal model studies and application of biophysics principles. As a result, these estimates are less certain.<ref name=":0" />		The health effects of high doses of other types of radiation have been studied by analyzing the health of exposed groups (for example, survivors of nuclear weapon attacks or nuclear power plant accidents). However, in the case of heavy ion radiation, estimates of the risk to astronauts are derived solely from animal model studies and application of biophysics principles. As a result, these estimates are less certain.<ref name=":0" />

Michel Lamontagne: /* Shielding Considerations */

2019-04-22T17:47:26Z

Shielding Considerations

← Older revision		Revision as of 18:47, 22 April 2019
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	==Shielding Considerations==		==Shielding Considerations==
			Heavy ions generate secondary radiation due to the very high energy of the particles. This means the thickness of radiation shielding needs to be increased over the requirements of solar storm shelters. This is particularly a consideration for long term settlements, where the accumulation of radiation damage from inadequate shielding might lead to increased cancer rates, neurological, and tissue damage over time.

	==References==		==References==
	<references />		<references />

JimL: Added concept of linear energy transfer.

2018-08-26T19:47:59Z

Added concept of linear energy transfer.

← Older revision		Revision as of 20:47, 26 August 2018
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	Heavy ions are charged particles heavier than alpha particles.<ref>Heavy ion. (1998, Jul 20). In ''Encyclopaedia Britannica. <nowiki>https://www.britannica.com/science/heavy-ion</nowiki>''</ref> They ~~consitute~~ 1% of cosmic radiation.<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>		Heavy ions are charged particles heavier than alpha particles.<ref>Heavy ion. (1998, Jul 20). In ''Encyclopaedia Britannica. <nowiki>https://www.britannica.com/science/heavy-ion</nowiki>''</ref> They constitute 1% of cosmic radiation.<ref>Schimmerling W. (2011, Feb 5). The Space Radiation Environment: An Introduction. <nowiki>https://three.jsc.nasa.gov/concepts/SpaceRadiationEnviron.pdf</nowiki></ref>


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	[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]		[[File:Cucinotta 2009 Fig. 4-3.png\|thumb\|412x412px\|<ref name=":0">Cucinotta FA, Durante M. (2009). Risk of Radiation Carcinogenesis. In ''Human Health and Performance Risks of Space Exploration Missions''. NASA-SP-2009-3405. <nowiki>https://humanresearchroadmap.nasa.gov/Evidence/reports/EvidenceBook.pdf</nowiki></ref>Comparison of the ionization effects on nearby molecules produced by ions with different masses.]]

	Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" />		Heavy ions passing through cells transfer more energy into a small volume, compared to other components of cosmic radiation. This concentrated effect can produce qualitatively different types of cell damage.<ref name=":0" /> Linear energy transfer (LET) is a measure of the amount of energy deposited in tissue per unit length of a particle's trajectory.<ref>Wagenaar JD. (1995, Oct 6). Linear Energy Transfer. In ''Radiation Physics Principles'' (Section 7.2.3). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.2/7_2.3.html</nowiki></ref> LET increases as a function of ion charge and mass, and decreases as a function of velocity.<ref>Wagenaar JD. (1995, Oct 6). Stopping Power. In Radiation Physics Principles (Section 7.1.2). <nowiki>http://www.med.harvard.edu/JPNM/physics/nmltd/radprin/sect7/7.1/7_1.2.html</nowiki></ref> Experimental irradiation of mouse cell cultures has indicated that heavy ions with an LET greater than 10 keV/μm are more likely to cause irreparable cell damage, compared to protons or alpha particles.<ref>Wilson JW, Cucinotta FA, Thibeault SA, Kim M-H, Shinn JL, & Badavi FF. (1997, Dec). In JW Wilson, J Miller, A Konradi, & FA Cucinotta, (Eds.), ''Shielding Strategies for Human Space Exploration'' (pp. 109-149). NASA Conference Publication 3360. <nowiki>http://hdl.handle.net/2060/19980137598</nowiki></ref>

	The health effects of high doses of other types of radiation have been studied by analyzing the health of exposed groups (for example, survivors of nuclear weapon attacks or nuclear power plant accidents). However, in the case of heavy ion radiation, estimates of the risk to ~~astonauts~~ are derived solely from animal model studies and application of biophysics principles. As a result, these estimates are less certain.<ref name=":0" />		The health effects of high doses of other types of radiation have been studied by analyzing the health of exposed groups (for example, survivors of nuclear weapon attacks or nuclear power plant accidents). However, in the case of heavy ion radiation, estimates of the risk to astronauts are derived solely from animal model studies and application of biophysics principles. As a result, these estimates are less certain.<ref name=":0" />

	==Shielding Considerations==		==Shielding Considerations==