There are plenty of other isotopes that undergo a variety of decay processes
depending on the original source, be it lead, uranium, thorium etc. Rn220
also undergoes significant alpha decay.
222 comes from a Radium decay. However, ALL Radon gas IS radioactive (i.e.
it decays no matter what the isotope).
No Radon is a nuclear stable gas, it is too dense.
The following Radon isotopes have alpha decay:
195,196,197,198,199,200,201,202,203,204,205,206,207(with
Positron),208,209(with Positron),210,211(with
Positron),212,213,214,215,216,217,218,219,220,221,222 (L50 of 3.823 days),
223 to 228 are beta decay.
All isotopes are unstable. Noble just relates to electronic configuration
not nuclear stability.
Kind regards
Russell Corbyn MRSC FGS
-----Original Message-----
From: Contaminated Land Management Discussion List
[mailto:[log in to unmask]] On Behalf Of Chris
Dainton
Sent: 14 April 2011 13:05
To: [log in to unmask]
Subject: Re: Sorry another gas related one - radon
Hello all
The radiological risk is not actually due to radon gas. You inhale and
exhale the gas (inert noble gas) and the chances of it decaying whilst in
the lung during a breath are small (and the volume of air in your lung is
small).
The main risk is due to the alpha decay (of mainly Rn222) to its daughter
products, principally longer lived daughters of Po and Pb (which are
obviously solids).
These plate onto dust, which when inhaled can lodge in the lung. These then
decay (eventually down to stable lead), giving off nice alpha (He) particles
along the way (this gives the main radiation dose) and some beta/gamma
radiation (the decay chain is pretty complicated).
Dare I say it?, a true killer dust.
The passive 'radon' detectors are again a bit of a misnomer. They are bits
a plastic that are marked by tracks of the beta particles from daughter
product in dust that has come to rest on the plastic. The tracks are then
counted, assumptions made and the radiation level estimated.
<forgive any inaccuracies, this is from deep in my memory from a radiation
protection MSc 22 years ago! Please feel free to correct >
Chris Dainton
Peak Environmental Solutions
(who lives & works in an area with high background lead, cadmium and radon).
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