Fast bunch to bunch feedback is necessary to control instabilities caused by coupled bunch oscillations in high intensity machines. A time domain active feedback scheme is discussed with focus on effective error detection using simple analog filters. Fast electronic switches direct each beam bunch signal from a beam pickup to a corresponding filter. The filters are excited at steady states. The...

A programmable longitudinal feedback system based on four AT&T 1610 digital signal processors has been developed as a component of the PEP-II R&D program. This Longitudinal Quick Prototype is a proof of concept for the PEP-II system and implements full speed bunch-bybunch signal processing for storage rings with bunch spacings of 4 ns. The design implements, via software, a general purpose feed...

In this paper, we deal with the issues of single-beam collective effects (the bunch lengthening and the transverse mode-coupling instability) and coupled-bunch beam instabilities due to RF cavities and the resistive-wall beam pipes in the KEK B-factory. The transit ion problem and coupled-bunch instabilities due to photo-electrons will be discussed in other publications.

Yelp is one of the largest online searching and reviewing systems for kinds of businesses, including restaurants, shopping, home services et al. Analyzing the real world data from Yelp is valuable in acquiring the interests of users, which helps to improve the design of the next generation system. This paper targets the evaluation of Yelp dataset, which is provided in the Yelp data challenge. A...

(This parametrization may differ slightly from others in that we take detV23 = detV12 = −1.) The error bars are such that θ31 is consistent with 0, in which case the CP violating phase e iφ does not enter. We could suppose either that the entries in V represent a bunch of meaningless numbers (possibly varying from domain to domain in the universe as advocated by some theorists of great sophisti...

The pivoting strategy of Bunch and Marcia for solving systems involving symmetric indefinite tridiagonal matrices uses two different methods for solving 2 × 2 systems when a 2 × 2 pivot is chosen. In this paper, we eliminate this need for two methods by adding another criterion for choosing a 1× 1 pivot. We demonstrate that all the results from the Bunch and Marcia pivoting strategy still hold....

KEKB is a double-ring energy-asymmetric electronpositron collider, now operating at KEK. In order to achieve a luminosity on the order of 1033=cm2=sor more, a very large number of bunches are stored. At present, the number of bunches is about 1,200 and the bunch spacing is 8 ns, in the usual physics operation. Consequently, strong coupled-bunch instabilities have been observed. In order to supp...

Electron cloud induces a transverse wake force which makes a correlation between bunch by bunch, namely a transverse displacement of a bunch causes a perturbation of electron cloud, which affects the transverse motion of following bunches. The correlation can be regard as a kind of wake force. We study the coupled bunch instability caused by electron cloud in drift space and in weak solenoid fi...

Longitudinal and transverse phase space information has been obtained from a statistical analysis of fluctuations in the radiation spectrum of an electron bunch. Uncorrelated shot noise fluctuations in longitudinal beam density result in incoherent radiation with a spectrum that consists of spikes, with width inversely proportional to the bunch length. Measurements were performed at l 620 nm on...