| Paper | Title | Page |
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| TUPS01 | Rf-enhanced Schottky Signals from Electron-cooled Coasting Beams in a Heavy-Ion Storage Ring | |
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Measurements at the Test Storage Ring (TSR) of the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg, Germany, have shown that the signals from coasting, electron-cooled ion beams, picked up using a Schottky-noise electrode, can be significantly enhanced in amplitude by simultaneous exposure of the beams to an off-resonant radio frequency (rf) signal*. The detuning between the rf signal and the closest harmonic of the beam revolution frequency is so large that beam bunching is not possible. Thus no net locking of the average revolution frequency to an integer fraction of the rf occurs. Instead, the centre frequency of the pick-up signal closely follows the revolution frequency imposed onto the ions by the electron cooler of the storage ring. For beams of protons and bare carbon ions, this rf-perturbation resulted in up to 13-fold enhancement of the pick-up signal amplitude compared to the pure Schottky-noise spectrum of the electron-cooled beams. While the origin of this pick-up signal amplification is still under investigation, the technique is now routinely employed at the TSR in order to measure the revolution frequencies of low-current ion beams, whose unperturbed Schottky spectra are too faint to be detectable under normal circumstances.
* C. Krantz et al., NIM A 629 (2011), 1-5 |