Interaction of an electron beam with a femtosecond laser pulse co-propagating through a wiggler at the ALS produces large modulation of the electron energies within a short ~100 fs slice of the electron bunch. Propagating around the storage ring, this bunch develops a longitudinal density perturbation due to the dispersion of electron trajectories. The length of the perturbation evolves with a ...

Transverse bunch-by-bunch feedback systems for damping coupled-bunch instabilities in the KEKB rings have been working well since the early stages of the commissioning of the rings. Beam diagnostic systems that are the part of the bunch feedback systems, such as bunch current monitors, betatron-tune measurements systems, and bunch oscillation recorders, have been playing important roles in the ...

For the successful operation of various accelerator facilities a detailed bunch characterization is required. A complete description can be achieved using various diagnostic systems installed along an accelerator beamline. Ideally the diagnostic should be able to measure parameters of a single bunch in a non-destructive manner. For bunch length measurements this results in a complicated task es...

Single-bunch and coupled-bunch instability mechanisms in both longitudinal and transverse planes are reviewed. Stabilization by Landau damping, linear coupling, or feedbacks are also discussed. Benchmarking with some instability codes are shown as well as several experimental results. INTRODUCTION Two approaches are usually used to deal with collective instabilities. One starts from the single-...

It is shown that an undesirable curvature of the wave front of a two-dimensional nonlinear wake wave, excited in uniform plasma by a relativistic charged bunch or laser pulse, may be compensated by radial change of the equilibrium plasma density.

rashe grape cultivar grows in kurdistan province in rain fed conditions. microclimate conditions have a great effect on grape berry quality. information about changes in grape berry composition in the relation to climate changes is limited. in order to measure the effects of slope and altitude on some grape berry chemical composition, a study was conducted on grape cv. ‘rasheh’ in university of...

BACKGROUND The study on phytochemical difference between red and black goji berry is limited. METHODS Antioxidant activities and phenolic profiles in terms of total phenol content, total flavonoid contents, condensed tannin content, monomeric anthocyanin content, and total carotenoid content of red goji berry (Lycium barbarum) and black goji berry (L. ruthenicum) were compared using colorimet...

The Robust Conjugate Direction Search (RCDS) [1] optimizer is applied for online optimizations of the ESRF accelerators. This paper presents the successful application of the algorithm in reducing vertical emittance, improving injection efficiency and increasing lifetime. A new set of sextupole settings to increase chromaticity has been obtained with lifetimes comparable to the existing one. Th...