system
Given the following post, respond as if you're commenting on Reddit:
human
Alpha and Beta rays can barely get through a sheet of paper, How much mass do you need to block gamma rays?
gpt
Typical gamma ray shielding you find lying around in a nuclear physics laboratory is blocks of lead a few inches thick.

If you shoot a monochromatic, collimated beam of gamma rays directly at a piece of material, the gamma ray intensity falls off exponentially as a function of distance into the material.

The exponential decay constant is called the "attenuation coefficient", and it grows rapidly with increasing atomic number. That's why materials like lead are good for gamma ray shielding.