Electromagnetic traps for charged and neutral particles

The first part of this lecture reviews the physics of dynamic stabilization of ions in two-and three-dimensional radio frequency quadrupole fields, to build the quadrupole mass spectrometer and the ion trap. In the second part, it reports on trapping of neutral particles with emphasis on an experiment with magnetically stored neutrons. The ion trap works as ion source and mass spectrometer, it became the most sensitive mass analyzer available. Penning trap is a quadrupole ion trap but with only a dc voltage applied in special polarity. Also a magnetic field of certain direction is applied. The ions perform a resulting rotation. This trap is of advantage if magnetic properties of particles have to be measured, as Zeeman transitions or cyclotron frequencies. it can be used to measure the anomalous magnetic moment of the electrons. The principle of confining neutral particles is demonstrated using a magnetic bottle. It depends on focusing neutral atoms and molecules by means of multipole fields, making use of Zeeman or Stark effect. The magnetic traps were realized for atoms and neutrons. The analysis of the measurements by the magnetic storage ring indicates that the intrinsic storage time of the ring for neutrons is at least one day. (author). 30 refs., 18 tabs