Transition radiation in the x-ray region (TR) is produced by relativistic charged particles when they cross the interface of two media of different dielectric constants. The emitted radiation is the homogeneous difference between the two inhomogeneous solutions of Maxwell's equations of the electric and magnetic fields of the moving particle in each medium separately. In other words, since the electric field of the particle is different in each medium, the particle has to "shake off" the difference when it crosses the boundary. The total energy loss of a charged particle on the transition depends on its Lorentz factor γ = E / mc and is mostly directed forward, peaking at an angle of the order of 1/ γ relative to the particle's path. The intensity of the emitted radiation is roughly proportional to the particle's energy E.