or

Well, an interesting question indeed.

The basic principle for the production of X-ray is by deccelerating very fast moving electrons, so here might arise a question what happens to the energy of electrons? The energy of electrons is transferred to X-rays(minimum) and Heat energy. 

How do we deccelerate the fast moving electrons?

Simply by resistance force, for a fast moving electron, the energy possessed by it must be high, so we deccelerate the electrons by a target material which is of high atomic mass and has high melting point. Well, high melting point is used to prevent the melting of target element due to evolution of tremendous heat energy while decceleration, and high atomic mass to oppose the electrons motion, for efficient decceleration, as efficient decceleration means greater production of X rays.

There is also a cooling chamber connected to the targer element to extract heat energy while decceleration, and the target element is inclined at an angle nearly of 45 degrees so the X rays can be directed away from the Coolidge tube, i.e. in outward direction.

There is a low dc supply connected to the coil from where electrons are ejected and high dc potential to accelerate the electrons by great amount, so that the electrons possess more Kinetic energy and more KE gets converted to X rays.

The intensity of X rays are controlled vy low dc potential, i.e. filament current as it determines no. Of electrons undergoing decceleration.

The quality of x rays are dtermined by the high dc potential as more potential means more energy to electrons and greater frequency of x rays produced, increasing penetrating power or quality of X rays.

eV=(1/2)mv^2

eV=hf(Considering all energy is                               converted to X rays)

HOPE THIS MIGHT BE HELPFUL.