4. X-rays from an x-ray tube are Bragg reflected as shown in the figure below from the planes of a calcite crystal spaced 0.3036 nm apart. Photons of wavelength 1 = 0.3654 nm emerge from the crystal at an angle a with respect to their initial direction (see figure) and are Compton scattered through an angle of 90- as they pass through a second material. a. Find the angle a that the diffracted photon forms with its initial direction. b. What is the minimum accelerating voltage I'acc that would produce a photon of the given wavelength? c. How much energy was lost by the photon, and where did the energy go? 90 VACC