Abstract
A new energy-spread feedback control system using nondestructive energy-spread monitors has been developed in order to control and stabilize the energy spreads of single-bunch electron and positron beams in the KEKB injector linac. A well-controlled feedback system has been successfully working in daily operation not only for keeping the injection rate higher along with the beam-orbit and energy-feedback control system, but also for reducing the background level to the KEKB collider experiment. The energy spreads of the injection beams have been well stabilized within $0.33\ifmmode\pm\else\textpm\fi{}0.01%$ and $0.50\ifmmode\pm\else\textpm\fi{}0.02%$ ($0.55\ifmmode\pm\else\textpm\fi{}0.06%$) for the electron beam and the first (second) bunch of the high-current primary electron beam for positron production at the $180\ifmmode^\circ\else\textdegree\fi{}$ arc, respectively, and within $0.39\ifmmode\pm\else\textpm\fi{}0.01%$ ($0.36\ifmmode\pm\else\textpm\fi{}0.03%$) for the first (second) bunch of the positron beam at the end of the injector linac through the energy-spread feedback control system under the nominal operation condition. In this report we describe in detail the energy-spread feedback control system using nondestructive energy-spread monitors with multi--strip-line electrodes and their performance in KEKB operation.
Highlights
It is of fundamental importance to control and stabilize the acceleration and transport of bunched beams without any instabilities in high-energy accelerators in order to increase the luminosity in a collider experiment
The results indicate that the energy-spread monitors (ESMs) detected the synchronous variations of the energy spread to the rf phase of the subbooster klystron with a good sensitivity
The performance of the energy spread feedback control was investigated and the feedback parameters were tuned in the beam test under the nominal operation condition for KEKB injection
Summary
It is of fundamental importance to control and stabilize the acceleration and transport of bunched beams without any instabilities in high-energy accelerators in order to increase the luminosity in a collider experiment It is strongly required for so-called factory colliding machines to attain higher peak luminosities, and higher integrated luminosities in order to reduce the statistical errors to be as small as possible in physics analysis. The two-bunch injection scheme has enabled us to boost the injection rate of the positron beam by a factor of 2 While these feedback control systems contribute to keep stable operation of the injector linac, it is important to stabilize the energy spread in order to keep the injection rate higher, and to reduce the background level to the detector and the radiation damage of the accelerator components. The dedicated energy-spread feedback control system with nondestructive energy-spread monitors (ESMs) helps to cure the energy spread of the beams; in particular, this system is expected to control stable acceleration and transport of the high-current primary electron beam in order to produce a higher amount of positrons
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
