Measurement of the excitation of the coupling resonance Q/sub h/-Q/sub v/=0

To take advantage of the large resonance-free regions close to the diagonal Q/sub h/=Q/sub v/ in the tune diagram, the Intersecting Storage Rings (ISR) operate with nearly equal tunes. Thus, the excitation of the coupling resonance Q/sub h/-Q/sub v/=0 is of importance and this has stimulated the study of its effects, the measurement of its excitation by axial and skew quadrupole fields and its compensation. A complex coupling coefficient C can be defined in terms of axial and skew quadrupole fields, and the unperturbed machine parameters. An electronic device has been built to measure mod C mod by kicking a small beam and analysing the coherent oscillation. (5 refs).