Calculation of Optimum Angle of Attack to Determine.
The concept of cross section, as its name suggests, is that of effective area for collision. The cross section of a spherical target isIn aiming a beam of particles at a target which is much smaller than the beam, as in the Rutherford scattering

The concept of cross section, as its name suggests, is that of effective area for collision. The cross section of a spherical target is

In aiming a beam of particles at a target which is much smaller than the beam, as in the Rutherford scattering experiment, the cross section takes on a statistical nature.

Rutherford worked out the scattering cross section for alpha particles of kinetic energy KE scattering off a single nucleus with atomic number Z. The cross section for scattering at a greater angle than some chosen angle is