A new method using a streak camera to monitor the particle density distribution in three dimensions in space was developed for the LEP (Large European Electrons Positrons collider). This paper provides a basic overview of the experiment. The synchrotron radiation emitted by the particles creates the image of the density distribution of particles in the bunches. The optical set‐up allows us to see the front view or the top and side view of the photon bunch simultaneously at successive turns. The practical limits of our set up are discussed and some examples of bunch oscillations in three dimensions are given. ©1995 American Institute of Physics.