The video shows the difference in cosmic radiation intensity at ground level at Paris, Palais de La Découverte and in altitude at 2777 m, Pic du Midi in a Phywe PJ45 cloud chamber. Dimension of the surface of the machine is 45x45 cm. There is roughly the same quantity of electronic component (the thin erratic trails made of positons and electrons) because the intensity of gamma ray at 3000 m and in sea level has the same order of magnitude (0.01 cm-2.s-1.sr-1 for E above 30MeV). The electrons and positons are produced by photoelectric effect, Compton effect or pair creation by the interaction gamma ray in matter. The wall of the cloud chamber (total 1 cm of glass) is matter where production of electronic particle can occur.

There is a difference about the hadronic component (proton and neutron). There is about 10x time more proton in 3000 m than in sea level (and neutron too) so we can see many more proton interaction in the Pic du Midi 's cloud chamber than the one in Paris. Proton leave thick straight trails and when a proton (or a neutron) hit a nucleus in the matter of the cloud chamber, it can produce other protons (spallation reaction). See the other video about observation of cosmic ray in altitude. The website http://www.cloudylabs.fr will give more explanations about the nuclear events observed.