#zettel #research/radiography/electron-clouds sourced from: [[GM 2025-03-13]] # An electron cloud is generated by a single fast electron An electron cloud as a collection of liberated charges in a semiconductor material like 3D-CZT that all brought on by the transfer of energy rom a photon to a single electron. This electron has a corresponding energy which must be dissipated via collisional and radiative loses as discussed by the [[Bethe Formula for Stopping Power]]. So as the electron scatters, it will deposit most of its energy depending at specific points along it track, creating a characteristic electron cloud shape. One time I put my foot in my mouth at the Group Meeting and demonstrated that I misunderstood the idea of an electron cloud, I was more focused on the "event cloud", that is, a set of electron clouds all sourced from the same source photon (i.e. a photon that might have Compton scattered twice and then been photo electrically absorbed has three electron clouds.) ## Related Thoughts: - Matt Petryk called the collection of electron clouds from a single photon event an "event cloud", because this is how we discuss them in the context of our detectors: there may be many photon interactions in a single "photon event".