Curie: Difference between revisions
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[[ | [[File:Curie_and_radium_by_Castaigne.jpg|300px|thumb|right|Figure 1 The Curies and another person doing experiments with radium. <ref>Drawn by André Castaigne - http://ihm.nlm.nih.gov/images/B30095 downloaded February 17th, 2020 from Wikimedia commons.</ref>]] | ||
<onlyinclude>The '''curie''' or '''Ci''' is the [[SI|non-SI]] [[units|unit]] for [[radioactive decay]] measuring the [[radioactivity]] of a substance.</onlyinclude> | <onlyinclude>The '''curie''' or '''Ci''' is the [[SI|non-SI]] [[units|unit]] for [[radioactive decay]] measuring the [[radioactivity]] of a substance.</onlyinclude> There are several different units for radioactivity with the official SI unit for radioactive decay being the [[Becquerel]]. The curie specifies the amount of [[ionizing radiation]] [[energy]] that is emitted from an unstable [[isotope]] as it decays.<ref>U.S.NRC. (06, 21, 2016). Curie (Ci) [Online]. Available: http://www.nrc.gov/reading-rm/basic-ref/glossary/curie-ci.html</ref> It was named after Pierre and Marie Curie, both physicists who won the Nobel Prize in Physics in 1903 (alongside Henri Becquerel) for their work on radioactivity. <ref>RUTHERFORD, E. Radium Standards and Nomenclature Nature 84, 430–431 (1910). https://doi.org/10.1038/084430a0</ref><ref>UNEP. “Radiation Effects and Sources,” United Nations Environment Programme, Austria. Sci. Rep. 978-92-807-3517-8. 2016. </ref> The Ci measures the amount of disintegrations per second coming from a decaying element such as [[Uranium]]. Originally, the curie was a comparison of the activity of a sample to the activity of one gram of radium, which was measured at 37 billion disintegrations per second.<ref>E.E. Anderson. “Units of Radiation and Radioactivity.” Public Health Reports, Oak Ridge National Laboratory, Oak Ridge, Tenn. Vol. 67, No. 3, March 1952</ref> As an example, a radioactive sample undergoing 74 billion disintegrations per second has an activity of 2 curies. | ||
The ability to measure the activity of a substance | The ability to measure the activity of a substance has many practical applications. For example, measuring the activity of a substance can help determine the [[half life]] of a sample. One useful application involving half life is radioactive dating, which is used to determine the age of [[rock]]s and other materials, which is how the [[time scale of the universe|age of the Earth]] is known.<ref>The TalkOrigins Archive, "The Age of the Earth" [Online], Available: http://www.talkorigins.org/faqs/faq-age-of-earth.html</ref> | ||
The curie is a fairly large unit of measurement, thus it is commonly prefixed to represent a wide range of different activity level, for example: | The curie is a fairly large unit of measurement, thus it is commonly prefixed to represent a wide range of different activity level, for example: | ||
* | * 1 Picocurie (pCi): is 1 million millionth of a curie (<math>1 \times 10^{-12}</math> Ci). Picocuries are used in measuring the typically small amount of radioactivity in air and water.<ref> US Army Corps of Engineers. "How Big is a Picocurie?" Accessed Jan.30, 2019. [Online] Available: https://www.lrb.usace.army.mil/Portals/45/docs/FUSRAP/FactSheets/fusrap-fs-picocurie.pdf </ref> | ||
* | * 1 Megacurie (MCi) is 1 million curies (<math>1 \times 10^6</math> Ci). Megacuries are used in measuring the very large amount of radioactivity released from nuclear weapons.<ref>Federal Radiation Council, 1963. "Estimates and evaluation of fallout in the United States from nuclear weapons testing conducted through 1962". US Government Printing Office. Accessed Jan.30, 2019. </ref> | ||
= | ==Radiation-related quantities== | ||
The following table shows radiation quantities in SI and non-SI units.<ref>NIST. (2016, February 10). Chapter 5. Guide to the SI, Units Outside the SI [Online]. Available: http://www.nist.gov/pml/pubs/sp811/sec05.cfm</ref><ref>NIST. (2016, February 19). Chapter 4. Guide to the SI, The Two Classes of SI Units and the SI Prefixes [Online]. Available: http://www.nist.gov/pml/pubs/sp811/sec04.cfm</ref> | The following table shows radiation quantities in SI and non-SI units. Both the non-SI and SI units represent the same quantities, expressed differently.<ref>NIST. (2016, February 10). Chapter 5. Guide to the SI, Units Outside the SI [Online]. Available: http://www.nist.gov/pml/pubs/sp811/sec05.cfm</ref><ref>NIST. (2016, February 19). Chapter 4. Guide to the SI, The Two Classes of SI Units and the SI Prefixes [Online]. Available: http://www.nist.gov/pml/pubs/sp811/sec04.cfm</ref> | ||
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Revision as of 20:09, 17 February 2020
Figure 1 The Curies and another person doing experiments with radium. [1]
The curie or Ci is the non-SI unit for radioactive decay measuring the radioactivity of a substance. There are several different units for radioactivity with the official SI unit for radioactive decay being the Becquerel. The curie specifies the amount of ionizing radiation energy that is emitted from an unstable isotope as it decays.[2] It was named after Pierre and Marie Curie, both physicists who won the Nobel Prize in Physics in 1903 (alongside Henri Becquerel) for their work on radioactivity. [3][4] The Ci measures the amount of disintegrations per second coming from a decaying element such as Uranium. Originally, the curie was a comparison of the activity of a sample to the activity of one gram of radium, which was measured at 37 billion disintegrations per second.[5] As an example, a radioactive sample undergoing 74 billion disintegrations per second has an activity of 2 curies.
The ability to measure the activity of a substance has many practical applications. For example, measuring the activity of a substance can help determine the half life of a sample. One useful application involving half life is radioactive dating, which is used to determine the age of rocks and other materials, which is how the age of the Earth is known.[6] The curie is a fairly large unit of measurement, thus it is commonly prefixed to represent a wide range of different activity level, for example:
- 1 Picocurie (pCi): is 1 million millionth of a curie ( Ci). Picocuries are used in measuring the typically small amount of radioactivity in air and water.[7]
- 1 Megacurie (MCi) is 1 million curies ( Ci). Megacuries are used in measuring the very large amount of radioactivity released from nuclear weapons.[8]
The following table shows radiation quantities in SI and non-SI units. Both the non-SI and SI units represent the same quantities, expressed differently.[9][10]
| Quantity | Name | Symbol | Unit | System |
|---|---|---|---|---|
| Exposure | Roentgen | R | 2.58x10-6 C/kg | Non-SI |
| Absorbed Dose | Rad Grey |
rad Gy |
10-2 Gy Jkg-1 |
Non-SI SI |
| Activity | Curie Becquerel |
Ci Bq |
3.7x1010 Bq s-1 |
Non-SI SI |
| Dose Equivalent | Roentgen Equivalent Man Sievert |
rem Sv |
10-2 Sv Jkg-1 |
Non-SI SI |
Curie Unit Converter
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References
- ↑ Drawn by André Castaigne - http://ihm.nlm.nih.gov/images/B30095 downloaded February 17th, 2020 from Wikimedia commons.
- ↑ U.S.NRC. (06, 21, 2016). Curie (Ci) [Online]. Available: http://www.nrc.gov/reading-rm/basic-ref/glossary/curie-ci.html
- ↑ RUTHERFORD, E. Radium Standards and Nomenclature Nature 84, 430–431 (1910). https://doi.org/10.1038/084430a0
- ↑ UNEP. “Radiation Effects and Sources,” United Nations Environment Programme, Austria. Sci. Rep. 978-92-807-3517-8. 2016.
- ↑ E.E. Anderson. “Units of Radiation and Radioactivity.” Public Health Reports, Oak Ridge National Laboratory, Oak Ridge, Tenn. Vol. 67, No. 3, March 1952
- ↑ The TalkOrigins Archive, "The Age of the Earth" [Online], Available: http://www.talkorigins.org/faqs/faq-age-of-earth.html
- ↑ US Army Corps of Engineers. "How Big is a Picocurie?" Accessed Jan.30, 2019. [Online] Available: https://www.lrb.usace.army.mil/Portals/45/docs/FUSRAP/FactSheets/fusrap-fs-picocurie.pdf
- ↑ Federal Radiation Council, 1963. "Estimates and evaluation of fallout in the United States from nuclear weapons testing conducted through 1962". US Government Printing Office. Accessed Jan.30, 2019.
- ↑ NIST. (2016, February 10). Chapter 5. Guide to the SI, Units Outside the SI [Online]. Available: http://www.nist.gov/pml/pubs/sp811/sec05.cfm
- ↑ NIST. (2016, February 19). Chapter 4. Guide to the SI, The Two Classes of SI Units and the SI Prefixes [Online]. Available: http://www.nist.gov/pml/pubs/sp811/sec04.cfm