U.S. Particle Accelerator School

Beam Experiments course

Sponsoring University:

University of California, Berkeley


Beam Experiments - Methods and Theory


Albert Hofmann and Malika Meddahi, CERN

Beam measurements are treated with emphasis on the underlying beam dynamics. A large class of transverse experiments can be carried out with beam position monitors for detection and a deflecting magnet for influencing the beam. In the static case, the monitors give the closed orbit and its change due to a deflection reveals the beta function. In the dynamic case, observing betatron oscillations driven by a fast deflector or an instability gives information on the tunes, beta functions and phase advances or the modes and growth rates of instabilities. The correlation between excitation and response (i.e., Beam Transfer Function and Green's Function) can be used to measure frequency distributions of the particles, Landau damping and wall impedances. With fast intensity monitors and cavity modulation corresponding measurements can be carried out in the longitudinal plane. The synchrotron radiation emitted by the relativistic particles is a useful tool to obtain the transverse and longitudinal beam dimensions and to observe internal modes of bunch oscillations. The course concentrates on measurements in circular accelerators. Some experience with beams or an introductory course on accelerators is required.