Ratio of cosmic and cosmogenic radiation

[snorkack]

Air stops most cosmic radiation.
Yet some particles do reach sea level.
The cosmic radiation at sea level is estimated at around 300 microsieverts per year.
Cosmic radiation also causes nuclear reactions in air that stops it.
Many isotopes created by cosmic radiation are stable, or short lived and remain in air.
Heaviest common nucleus in air is O-16. Of nuclei lighter than 16, only 4 are radioactive but have half-life over 21 minutes. These are T (12 years), Be-7 (53 days), Be-10 (1,5 million years) and C-14 (5700 years).
What is the ratio of cosmogenic radiation to cosmic radiation on sea level?

 

[Astronuc]

What is the ratio of cosmogenic radiation to cosmic radiation on sea level?

It's an interesting question. I'm trying to find a good answer. One has to look at the attenuation of cosmic radiation, and types, and then look at the induced-activity in the air and at the surface - water vs plant vs mineral.

Muons make up more than half of the cosmic radiation at sea level, the remainder being mostly electrons, positrons and photons from cascade events. (Richtmyer)

http://hyperphysics.phy-astr.gsu.edu/hbase/astro/cosmic.html#c2

See Figure 24.3 http://pdg.lbl.gov/2011/reviews/rpp2011-rev-cosmic-rays.pdf

Some information on cosmogenic production here - http://www.whoi.edu/fileserver.do?id=133844&pt=2&p=146949

 

[raining Pete]

The ratio of cosmogenic radiation to cosmic radiation on sea level is difficult to determine precisely since it depends on various factors such as location, altitude, and time of year. However, it is generally estimated to be around 1-2% of the total cosmic radiation at sea level. This means that the majority of cosmic radiation is stopped by air, but a small percentage still reaches sea level and contributes to the overall radiation exposure.