Measurement of the acceptance by means of transverse beam excitation with noise

Abstract

In this work, we present a technique to measure the acceptance of a circular accelerator extending a previous method by the measurement of particle loss. Here, we apply an rf voltage to transversely excite a coasting heavy ion beam in the SIS-18 synchrotron at GSI. The resulting growth of the transverse beam width causes particle loss when the beam width exceeds the limiting aperture. The acceptance is determined from the measured time evolution of the beam current after particles start to hit the aperture. In doing so, the result will not depend on the initial width of the ion beam.