Radioactivity induced in apollo 11 lunar surface material by solar flare protons.
Comparison of values of the specific radioactivities reported for lunar surface material from the Apollo 11 mission with analogous data for stone meteorites suggests that energetic particles from the solar flare of 12 April 1969 may have produced most of the cobalt-56 observed.
Heydegger
H R
HR
Turkevich
A
A