MULTIPOLE RANDOM ERRORS IN DAΦNE MAIN RINGS

In circular particle accelerators it is very important to minimize field errors in the magnets. These errors, that can be both systematic and random, can lead to a reduction of the dynamic aperture. In particular, systematic multipolar components arise from pole shaping, which usually differs from the ideal one, while random components come from mechanical tolerances and magnet assembly. In this note we deal with the effects of random field errors on the dynamic aperture of the DAΦNE main rings. Being very difficult to correlate these errors to their mechanical origins, we use experimental data from other machines in operation or construction (PEP, AGS, ALS) to estimate the magnitude of random components in our simulations. In the first part of this note we briefly describe the mechanical tolerances which are the source of random errors. In the second part we estimate the magnitude of the errors to be used in the tracking code. Finally we compare the dynamic apertures obtained with and without random components