The range of electrons with energy E (in MeV) in water is approximately what value?

The correct approach to determining the range of electrons in water relies on the relationship between the energy of the electrons and their range. In general, the range of electrons in a medium like water can be approximated using the straightforward formula, which indicates that the range is roughly half the energy of the electrons expressed in MeV.

In this context, if the energy of the electrons is represented as E (in MeV), the range of these electrons in water can be estimated as E/2 cm. This relationship is derived from empirical data and takes into account the interactions of electrons with matter, particularly in water, which is a common reference medium in dosimetry.

The significance of this estimation is rooted in the characteristics of electron interactions; as electrons lose energy primarily through ionization and excitation of atoms, their range in a material is proportionate to their initial energy. The factor of 1/2 in the range formula reflects a balance of energy loss mechanisms and the density of the medium, providing a convenient calculation for dosimetrists when working with electron beam therapies.

So, using E/2 cm helps professionals in medical dosimetry to quickly evaluate the expected behavior of electron beams in clinical settings, thereby assisting in radiation treatment planning and dose