Magnetic flux area S is where "B" is the magnitude of the magnetic field (the magnetic flux density) having the unit of Wb/m (tesla), "S" is the area of the surface, and "θ" is the angle between the magnetic field lines and the normal (perpendicular) to S. For a varying magnetic field, we first consider the magnetic flux through an infinitesimal area element dS, where we may consider the field to be constant: A generic surface, S, can then be broken into infinitesimal elements and the total magnetic flux through the surface is then the surface integral From the definition of the
Cross section (physics) not azimuthally symmetric, such as when the beam or target particles possess magnetic moments oriented perpendicular to the beam axis, the differential cross section must also be expressed as a function of the azimuthal angle. For scattering of particles of incident flux off a stationary target consisting of many particles, the differential cross section at an angle is related to the flux of scattered particle detection in particles per unit time by Here is the finite angular size of the detector (SI unit: sr), is the number density of the target particles (SI units: m), and is the thickness of