Suppose that we have a monochromatic non-diverging beam of x rays    that are incident on a slab of Pb. Inside the Pb plate there are three apertures (openings) that allow the beam of x rays to be incident on a water phantom as shown in the figure below. 

 (a)  In the compartment of water denoted by the dotted line, calculate:

     (i)  The number of photoelectric interactions per second, 

    (ii)   The number of Compton interactions per second 

    (iii)   The number of coherent scatters interactions per second.

    (iv)   The energy absorbed per second. 

(b)  What thickness of air  (d_air)  is needed in order that the number of Compton scatter interactions in air are the same as in the volume of water in (a)?

(c)  What thickness of bone (d_bone) is needed in order that the number of Compton scatter interactions in bone are the same as in the volume of water in (a)?