How to see trajectories of interacting particles?

Leaving a helical track behind

In our time, the visualization of tracks and vertices of particle interactions is done by computer processing of electrical signals caused by charged particles flying through so-called wire chambers. In the 80s, these came to replace bubble chambers where the charged particles leave a trail of vapor micro-bubbles of the liquefied gas filling a chamber — hydrogen, Freon, etc.. The bubbles rise, become visible, and then photos from several directions at once are taken, which gives a three-dimensional picture of the interaction. A trajectory bend of a charged particle in magnetic field allows calculation of particle’s momentum. Bubble chambers provide a relatively high spatial resolution of tracks, but require a lot of time preparing for the next event photography. Besides, they are not large enough to determine the radius of the bend of a high-energy-particle track. Moreover, analysis of the enormous number of background-event photos in modern experiments would last forever!

The bubble chamber photographed the tracks of elementary particles

This literally was a window into the micro-world.


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