Transverse bunch-by-bunch feedback systems for damping coupled-bunch instabilities in the KEKB rings have been working since the early stage of the commissioning of the rings. Stabilization of the beams with the system have been successful, permitting tests of higher beam currents and various filling patterns. The performance of these systems has been demonstrated under the normal physics run p...

A bunch-by-bunch longitudinal feedback system has been designed and built o control coupled-bunch instabilities in the PEP-I1 machine. A prototype system has been installed at the Advanced Light Source at LBNL. Programmable DSPs allow longitudinal feedback processing in conjunction with data acquisition or instrumentation algorithms. Here we describe techniques developed for different beam and ...

Compensation of multi-bunch beam loading is of great importance in the main linac of the Compact Linear Collider (CLIC). The bunch-to-bunch energy variation has to stay below 1 part in 10. In CLIC, the RF power is obtained by decelerating a drive beam which is formed by merging a number of short bunch trains. A promising scheme for tackling beam loading in the main linac is based on varying the...

We derive analytical expressions for external fields of a charged relativistic bunch with a circular cross section. At distances far from the bunch, the field reduces to the relativistic modified Coulomb form and in the near region, reproduce the external fields of a continuous beam. If the bunch is surrounded by conducting surfaces, the bunch self-fields are modified. Image fields generated by...

The perturbative approach for describing the underdense plasma–ultrarelativistic electron bunch system is developed,using the ratio n0 nb as a small parameter (nb-bunch,n0plasma electron densities). Focusing of the electron bunch emerged in the first approximation of the perturbative procedure as a result of the plasma electrons redistribution.Focusing gradient and strength for ultrarelativisti...

The use of synthetic retardants in polymeric insulated cables is not uncommon in the high voltage engineering to study electrical treeing phenomenon. However few studies on organic materials for the same investigation have been carried. .This paper describes the study on the effects of Oil Palm Empty Fruit Bunch (OPEFB) microfiller on the tree initiation and propagation in silicone rubber with ...

The increase in single processor speed based on Moore’s law alone will not be able to deliver the dramatic speedup needed in many beam tracking simulations to uncover very slowly evolving effects in a reasonable time. SLAC has embarked on an effort to bring the power of parallel computing to bear on such computations with the goal to reduce the turnaround time by orders of magnitude so that the...

In CESR, 9 trains of 4 or 5 bunches of electrons and positrons collide at the interaction point, but bypass each other in the arcs of the storage ring using electrostatically separated orbits (pretzels). The parasitic bunch crossings resulting from the use of pretzel separation causes the bunches to have different orbits and, thus, the luminosity to be sensitive to the relative transverse posit...

Banana (Musa spp.) is one of the most important food and cash crops in Kenya. However, most of the cultivars grown particulary the local ones are low yielders and are thus not very suitable for commercial production. To address this constraint, a study was conducted at Kenya Agricultural Research Institute, Thika to evaluate introduced improved cultivars for agronomic and yield characteristics....

In routine operation the Cornell Electron/positron Storage Ring, CESR, collides 9 trains of 4 or 5 bunches of electrons and positrons. The luminosity of individual bunch pairs can suffer if the transverse positions of those bunches are displaced differentially. This paper will present the results of studies of the effect of bunch–by–bunch or train– by–train variations in the luminosity by measu...