Fast on-line charged particle tracing in real magnetic fields

The work we present consists of the development of a computerised 3-D scann ing system running under LABVIEW(R). 3-D magnetic held measurements, form a n important application allowing a fast on-line determination of charged pa rticle trajectories in real magnetic fields. The set-up consists of a Hall- probe, movable in three dimensions, mimicking a charged particle entering a magnetic field with well-defined transport characteristics (energy, positi on, momentum). The measured local field components are used as input to a L ABVIEW(R) program, which calculates the local direction of the flight-path of the particle. Then the probe is moved along this direction with a predet ermined step-length. In this way, the real path of the charged particle is determined step by step automatically accounting for all magnetic field imp erfections. Trajectories can be determined without the measurement of the w hole 3-D field configuration. (C) 1999 Elsevier Science B.V. All rights res erved.