What is the approximate thickness of lead required to cut off a 10 MeV electron beam?

The approximate thickness of lead required to effectively attenuate a 10 MeV electron beam is around 5 mm. The reasoning behind this involves the concept of radiation shielding, specifically concerning electron beams.

Electrons lose energy primarily through interactions with matter, and their range in a material like lead can be estimated using known empirical data. For a 10 MeV electron beam, lead serves as an effective shielding material due to its high atomic number, which enhances the interaction probability between the electrons and the lead atoms.

Typically, the range of 10 MeV electrons is such that the required thickness to significantly attenuate the beam—essentially reducing the intensity to a level where it can be considered "cut off"—is in the vicinity of 5 mm. This results from the balance between adequately stopping the high-energy electrons while ensuring practical and efficient use in clinical settings.

In practice, other factors like scattering and the design of the shielding would also come into play, but the primary characteristic at this energy level indicates that around 5 mm of lead provides sufficient attenuation for application in medical dosimetry.