The following is a selected area electron diffraction pattern taken from a polycrystalline material (simulated, but similar to the real ones). The measured ring radius values are also shown for the first 5 rings. The diffraction pattern was taken in a TEM at an accelerating voltage of 200 keV and camera length of L = 2000 mm. The polycrystalline material has cubic crystal structure. a. Prove that the polycrystalline material has FCC structure. b. Index the ring pattern. c. Find the lattice constant a. R1 = 8.4 mm R2 = 9.6 mm R313.6 mm R4 15.8 mm 2 3 4 5