As photon energy increases, in which direction does the Compton electron get ejected?

As photon energy increases, the Compton electron is ejected more and more in the forward direction due to the principles of conservation of momentum and energy during the scattering event. In Compton scattering, a photon collides with a loosely bound electron, transferring some of its energy to the electron, which results in the electron being emitted from the atom.

With higher energy photons, they possess greater momentum and can impart this momentum to the electron more efficiently. As a result, the electron is more likely to be ejected at an angle that is closer to the direction of the incoming photon, which corresponds to the forward direction. The relationship between the initial photon energy and the scattering angle of the emitted electron is governed by the Compton formula, which shows that increased photon energy leads to smaller scattering angles for a given increase in the energy of the photon.

Thus, the correct interpretation of the behavior of the Compton electron with increasing photon energy indicates a tendency for the electron to be emitted more in the forward direction.