Bunch Length Measurement and the Beam Spectra Observation Through High Power RF Waveguide System
A wide-band pick-up, which is mounted on the wall of waveguide between the klystron and the RF cavity, has been developed for measuring beam spectra in KEKB. The spectrum between 5 GHz and 20GHz is taken to calculate the bunch length. And the synchrotron oscillation is observed as the side band of revolution peak. The bunch length and synchrotron frequency are measured under the different momentum compaction factors {alpha} and different total RF voltages Vc. Measured bunch length is compared with the measurement of streak camera.
Injection transient study using a two-frequency bunch length measurement system at the SSRF
The bunch length can be measured by comparison of two frequency components of a synchrotron beam signal. An online bunch length measurement system has been implemented based on this method. Working frequencies of 3 GHz and 500 MHz were selected, and the raw data was acquired by digital oscilloscope and was resampled and analyzed using the MATLAB software platform at bunch-by-bunch rate. The constructed system was employed to study the bunch length synchronous oscillation phenomenon during injection. The beam experiments demonstrated a time resolution of less than 0.5 ps.
A real time bunch-length monitor using the beam spectrum and measurements of bunch lengthening
Abstract A bunch length monitor used for detecting two frequency components of a beam spectrum has been developed for the TRISTAN accumulation ring (AR). The principle, design and performance of the monitor are described. The monitor comprises a stripline electrode, a coaxial cable and two identical synchronous detectors. Calibration of the monitor was carried out using the natural bunch length at a low beam current. The bunch length was measured at an injection energy of 2.5 GeV by the monitor and a streak camera. The imaginary part of the longitudinal coupling impedance was estimated by the potential well bunch lengthening and synchrotron tune shift.