Sector mass spectrometer

A sector instrument is a general term for a class of mass spectrometer that uses a static electric or magnetic sector or some combination of the two (separately in space) as a mass analyzer. A popular combination of these sectors has been the BEB (magnetic-electric-magnetic). Most modern sector instruments are double-focusing instruments (first developed by A. Dempster, K. Bainbridge and J. Mattauch in 1936) in that they focus the ion beams both in direction and velocity. A sector instrument is a general term for a class of mass spectrometer that uses a static electric or magnetic sector or some combination of the two (separately in space) as a mass analyzer. A popular combination of these sectors has been the BEB (magnetic-electric-magnetic). Most modern sector instruments are double-focusing instruments (first developed by A. Dempster, K. Bainbridge and J. Mattauch in 1936) in that they focus the ion beams both in direction and velocity. The behavior of ions in a homogeneous, linear, static electric or magnetic field (separately) as is found in a sector instrument is simple. The physics are described by a single equation called the Lorentz force law. This equation is the fundamental equation of all mass spectrometric techniques and applies in non-linear, non-homogeneous cases too and is an important equation in the field of electrodynamics in general. where E is the electric field strength, B is the magnetic field induction, q is the charge of the particle, v is its current velocity (expressed as a vector), and × is the cross product. So the force on an ion in a linear homogeous electric field (an electric sector) is: