Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

Storage Of Unprocessed Film
With x-rays generated up to 200 LV (?) , it is feasible to use storage
compartments lined with a sufficient thickness of lead to protect the film. At
higher kilovoltages, protection becomes increasingly difficult; hence, film
should be protected not only by the radiation barrier for protection of
personnel but also by increased distance from the source. At 100 kV, a 1/8
inche thickness of lead should normally be adequate to protect film stored in a
room adjacent to the x-ray room if the film is not in the line of the direct beam.
At 200 kV, the lead thickness should be increased to 1/4 inch. With million
volt x-rays, films should be stored beyond the concrete or other protective
wall at a distance at least five times farther from the x-ray tube than the area
occupied by personnel.
Charlie Chong/ Fion Zhang
Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980