I made a cloud chamber--with a very interesting result!

[ArtAndScience]

Hi! This is my first post here. I am a digital artist who develops interactive learning for science and engineering subjects, hence my
ID. Today, I built a simple 'cloud chamber' to detect atomic particle tracks--a photo is below. The particle source I used is a small button of
Am-241. Most of the tracks I observed seem to be either straight (alpha?) or curved (beta particles?). The one exception is the bulls-eye pictured below,
with two lobes (arrows)--two particles of opposite charge? I have never seen such a track in a cloud chamber in all I have seen--do you have any idea what it is?

 

The picture below is a composite of several shots taken of the trails.

 

 

Someone in another forum suggested the Am-241 button moved, leaving that mark. However, this is the first thing I checked. Below shows a sequence of shots at approx. 1 second intervals, with the "bull's-eye" visible in the middle frame, and the button has not moved.

Edited April 29, 2013 by ArtAndScience

[krash661]

i have no clue

Edited April 29, 2013 by krash661

[ArtAndScience]

Hi, and thanks for commenting. I really have no clue either, which is why I asked. I've watched a few videos of cloud chambers in action and did not spot anything similar. One question I asked myself--if a atom's nucleus were struck by a heavy particle (such as a neutron), or it spontaneously fissioned--could it be seen in a cloud chamber?