3. Monochromatic x-rays of wavelength 1 = 0.243 nm are produced in the following way: Electrons bombard a metal target in a standard x-ray tube, and the resulting radiation is reflected from a crystalline material, as shown in the figure below. a. What is the purpose of the crystal? b. What is the minimum accelerating voltage l'acc that could have produced x-rays of this ? c. The reflected x-rays go on to collide with a carbon block C, where their wavelength is shifted to 1' by the Compton effect. For the direction shown in the drawing, calculate the change in wavelength. d. Does the x-ray gain or lose energy in this process? Where does the energy go? What is the most striking assumption made by Compton in his analysis of this phenomenon? Carbon Vacc Crystal