Final answer:
To find the minimum lead equivalent for a bucky slot shield, we need to determine the thickness of lead that will absorb all but one in 1000 of the y rays. We can calculate this by setting up an equation and solving for the number of lead layers needed. In this case, we need 9 layers of lead that are each 0.170 mm thick.
Step-by-step explanation:
To find the minimum lead equivalent for a bucky slot shield, we need to determine the thickness of lead that will absorb all but one in 1000 of the y rays. Let's solve the problem step by step.
- We are given that half of the y rays from 99m Tc are absorbed by a 0.170-mm-thick lead shielding.
- The second layer of lead is of equal thickness to the first layer, so it also absorbs half of the y rays that pass through the first layer.
- To find the thickness of lead that absorbs all but one in 1000 of these y rays, we need to multiply the original thickness by a factor of 2n, where n represents the number of layers.
- Since we are looking for the thickness that absorbs all but one in 1000 y rays, we can set up the equation: (0.170 mm) x (2n) = 1 / 1000.
- Solving this equation, we find that n = 9, which means we need 9 layers of lead that are each 0.170 mm thick to absorb all but one in 1000 of the y rays.