Скачать или смотреть Compilation of Impressive Cosmic Ray Interactions in a Cloud Chamber (Altitude : 2877 m) [1080p]

The video show a compilation of protons interactions, electromagnetic shower and cosmic ray spallation in a Phywe PJ45 cloud chamber at 2877 m. The sequences come from 8 hours of recording with a HD camera. Dimension of the surface of the machine is 45x45 cm. There is no magnetic field in the chamber;
The cloud chamber was temporarily put in the Pic du Midi (French Observatory in the Pyrenees) in 2012 for the 100th anniversary of the discovery of cosmic ray.

As this altitude, there is about 10 times more neutron and proton than in sea level. Theses particles can interact with the matter and break some nucleus which release other protons and neutrons, alpha particles or deuteron. The density of ionisation in a trail is proportionnal to z²/v² where z is the charge of the particle and v it's velocity. Thus, a proton with a low kinetic energy will make more ionization so the trail will be bigger than the trail of a high energy proton. A 5 MeV (0.1c) proton have a range of 34 cm in air, a 10 MeV one, 1.1 m.
The range of an alpha particle of 10 MeV in air is 10.4 cm.

Their is also higly energetic gamma ray (or energetic incoming electrons !), which can make electromagnetic shower (electrons and positon) in the matter (wall of the room, or wall of the machine which is made with 1 cm of glass). Single e+/e- comes from muon or Pi0 decay, or from the 3 interactions process of gamma in matter (photoelectric, compton and pair creation).

See the website http://www.cloudylabs.fr for more pictures and annotations about theses nuclear events. Feel free to give your thought about any interactions of the video.