The particle's radius of curvature  is proportional to its momentum perpendicular to the beam (i.e. transverse momentum or ) according to the formula  (where  is the particle's charge and  is the magnetic induction), while the degree to which it drifts in the direction of the beam axis gives its momentum in that direction.
The size of a particle's curvature around the beam is directly proportional to its transverse momentum (momentum perpendicular to the beam) according to the formula , where  represents the charge and  indicates the magnetic field strength. The extent of drift along the beam axis reveals the particle's momentum in that direction.