TEST OF A DISPERSION SWEEP CORRECTION SYSTEM USING A CENTROID IN THE DIRAC BEAM LINE

A new proton beam position detector named ‘Centroid’ is placed in the DIRAC target station and is aligned with respect to the beam. Behind it there is a set of various targets used for the DIRAC experiment. The ‘Centroid’ itself collects the secondary electrons, which are emitted by the target when hit by the proton beam [1]. This provides an on-line verification of the beam position without obstructing the beam path by a screen, and without perturbing the experiment. A computer application then calculates the corrections needed to centre the beam in both planes as a function of time. This paper will explain how this is done.