diffusion region

Electrons incident onto a bulk specimen are repeatedly scattered while losing their energy and spread into the specimen until they stop. The volume where the diffusion (scattering) arises is called "diffusion region." The electron energy-loss is caused by the generation of secondary electrons or X-rays due to excitations of inner-shell electrons. The size of the diffusion region is proportional to 1.3th to 1.7th power and inversely proportional to the density of the specimen. The Monte Carlo method enables us to make simulations of the diffusion feature of electrons in the specimen.
It is noted that, when the conductive specimen is grounded, the incident electrons which lose their energy and spread in the specimen flow to the ground to cancel the imbalance of the electric charge in the specimen. The current flowing to the ground is called the absorbed current.

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