Visibility of the growth direction of an alpha-particle track in a diffusion cloud chamber

Abstract

The growth direction of an alpha-particle track in a diffusion cloud chamber can be observed with the naked eye. Unlike the track of a beta-particle, an alpha-particle track appears first at the beginning of its path and proceeds to the end of the path. However, the alpha-particle covers the path in less than 10 ns, which is inconsistent with the visibility of the track-growth direction. This inconsistency was attributed to the following reasons: the number of ion pairs per unit length in the path is very large compared with that of a beta particle, the ion density near the end of the path is larger than that near the beginning, and alcohol droplets have to grow to a diameter of about 3 μm for being able to be seen. The alcohol molecules have to diffuse from a distant place to the region where the ions are created by the alpha-particle and the diffusion time near the end of the path is longer than that near the beginning of the path. This phenomenon was examined by diffusion theory.

On the Track Extending in the Opposite Direction to the Passage of an Alpha-Particle in Diffusion Cloud Chamber

“…However, there are mysterious phenomena in the diffusion cloud chamber. First, though the passage time of an α-particle is less than 10 ns, tracks extend their whole length over tens of milli-seconds and therefore the extension state is visible as reported 1) in the past. In the reference 1) , the reason of the visibility of the track extension was mentioned as follows.…”

Thermodynamic and experimental evaluation of a cloud chamber for ultrafine particle detection

“…where 𝐶 𝑖 7 -𝐶 𝑖 9 are variables composed of comparable thermodynamic and system parameters similar to Eqn. (11).…”

“…Cloud chambers are one type of fundamental devices used to investigate the formation and evolution of aerosol processes in recent years [4,5]. These devices were initially used to detect charged particles [6,7] and subsequently extended to meteorological studies such as ice nucleation [8][9][10], atmospheric oxidation [11], and cloud microphysical processes [12].…”

Distance Education Methods: Video Analysis in Teaching Physics

“…An example of such an educational study can be the work «Observation of continuous and linear spectra of a substance. Determining the wavelength of light» [35]. For this purpose, the original spectrum images and those available in the Tracker file library can be used.…”