Assume a 2-D scenario in which a pellet filled with radiotracer is located at the origin. The pellet emits gamma rays in the xy plane and its radioactivity is A=0.54mCi as shown in Figure P8.7(a). The detector is made of a material with =0.64cm1 and thickness of b=2cm. (a) What is the average rate of photons per second hitting the detector (in photons per second)? (b) Find the efficiency of the detector at its center (that is, at x=0 ). A parallel hole collimator with septal thickness h=2.5mm, septal height l=8cm, and hole diameter d=5mm is added onto the detector, as shown in Figure P8.7(b). (c) What is the collimator resolution RC ? (d) Assume the intrinsic resolution of the detector is 1mm. What is the overall PSF of the camera knowing that both hC and hI are Gaussian? (e) Given the geometry, how many holes receive radiation that can hit the detector