Hello all, I just finished building an expansion cloud chamber this weekend and have started experimenting with it. Everything looks solid (vacuum, seal etc) but I'm curious about the role my electrostatic field, generated from a bug zapper and a circuit, plays in visualizing the ionizing radiation. I know it sweeps the air of charge. However, I'm not quite sure why it is so crucial to see the tracks my Americium 241 (taken from a smoke detector) produces through emission of alpha particles and the resulting ionization- I couldn't see anything without the electrostatic field. In short, I'm wondering specifically how an imposed neutral charge (electrostatic field) helps to see the tracks and how it can have such a profound influence on whether or not they are visualized. Thanks!