| |
Schottky signal measurements are a widely used tool for the determination
of longitudinal and transverse dynamical properties of hadron beams in
circular accelerators and storage rings. When applied to coasting beams,
it is possible to deduce properties as the momentum distribution. the
Qx,y-values and the average betatron amplitudes. Scientific
applications have been developed in the past few years, as well, namely
nuclear Schottky mass spectrometry and lifetime measurements. Schottky
signals from a coasting beam are random signals which appear at every
revolution harmonic and the respective betatron sidebands. Their
interpretation is more or less straightforward unless the signal is
perturbed by collective effects in the case of high phase space density.
Schottky signals from bunched beams reveal the synchrotron oscillation
frequency, from which the effective rf voltage seen by the beam can be
deduced. The detection devices can be broad-band or narrowband. The
frequency range is usually in the range between a few hundred kHz up to
about 150 MHz. In connection with stochastic cooling, Schottky signals
are used at frequencies up to 8 GHz. Narrow-band devices are needed if
signal-to-noise problems arise, e.g. in the case of antiproton beams.
Heavy ion beams require less effort, it is relatively easy to detect
single circulating highly charged ions.
|
|