Glossary of terms

Last revised: 28 June, 2004

Bequerel (Bq) and Bq/m³
Bequerel is the international standard unit for radioactivity; that is the rate that radioactive materials decay. One Bq is one decay per second. The US unit of radioactivity is the Curie(Ci). One Ci is 3.7x 10¹⁰ decays per second. Bq/m³ is the international unit for volumetric activity concentration. The relationship between activity concentrations is that 1 pCi/L = 37 Bq/m³

Dose units: RAD, REM, Gray(Gy), Sievert (Sv) and all that
There are some thorny details that I will omit in this definition to give you the basic idea: Dose is a measure of energy absorbed in matter. The basic units are RAD (US) and Gray (international). 1 Gy=100 RAD. Dose Equivalent includes the energy deposited and the effectiveness of that dose at producing damage in biological cells. The basic units are REM (US) and Sv (international). 1 Sv=100 REM.   Effective Dose Equivalent includes the sensitivity of the human organ to the Dose Equivalent. It is a new concept and is only given in units of Sv.TOP

picoCurie and pCi/L
The US unit of radioactivity is the Curie(Ci). One Ci is 3.7x 10¹⁰ decays per second. One picoCurie is 3.7x 10^-2decays per second or 3.7x 10^-2Bq.  pCi/L is the US unit for volumetric activity concentration. The relationship between activity concentrations is that 1 pCi/L = 37 Bq/m³TOP

radon
A nickname for the isotope ²²²Rn of the element Radon. ²²²Rn has a 3.8 day half-life, the longest of any Radon isotope. It is a noble gas generated by the decay of radium found in rocks and derived materials. It decays via alpha and beta emission through a series of short-lived progeny, ²¹⁸Po,²¹⁴Pb,²¹⁴Bi, ²¹⁴Po to a moderately long-lived (21 years) isotope of lead; ²¹⁰Pb. ²¹⁰Po is radon's last mortal daughter. She decays into ²⁰⁶PbTOP

radon progeny/decay products/daughters
The series of nuclei that are produced when radon decays
Nucleus: ²²²Rn > ²¹⁸Po>²¹⁴Pb>²¹⁴Bi> ²¹⁴Po> ²¹⁰Pb>²¹⁰Bi> ²¹⁰Po > ²⁰⁶Pb
Emits:                 a       a           b         b        a          b         b        a
Life:                   4d       3 min     27 min   20 min   <1ms    21y      5d         138d    stableTOP

Thoron
A nickname for the isotope ²²⁰Rn of the element Radon. ²²⁰Rn has a 55 second  half-life, much shorter than ²²²Rn. It is a noble gas generated by the decay of radium found in rocks and derived materials. It decays via alpha and beta emission through a series of short-lived progeny. It is not as common as radon in the environment. Indoors it is thought to contribute about 10% of the total airborne radiation dose.TOP

Mitigation
Mitigation is the process of reducing radon gas related exposure in the home or workplace. It usually involves a change in the building's structure or systems. Often it requires a new device or system to achieve the desired level of reduction.  Common mitigation techniques include increasing indoor ventilation (open windows, air-to-air heat exchangers), removing radon progeny from the air (filters, fans), or ventilating the soil surrounding the building.TOP

More to come....let me know if there are terms you would like to see defined.

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