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....

The small beam spot size at the interaction point of the Next Linear Collider (NLC) makes the luminosity sensitive to beam jitter. A mechanism for aligning the beams to each other which acts during the bunch-train crossing time (~260 ns) has been proposed to maintain luminosity in the presence of beam jitter. Conceptual designs of principal components of the system, a fast position monitor, a k...

Long (σz ∼ 500 μm) SLAC electron and positron bunches sent into dense plasmas (ne = 0.6 − 2.3 × 10 cm−3) are subject to a transverse two-stream instability called the self-modulation instability or SMI. We use numerical simulations to show that when the SMI saturates, the wakefield excitation reaches the nonlinear regime of the plasma wakefield accelerator (PWFA). We show that defocused particl...

In this method called Traveling Laser Focus (TLF), multi-cell microstructures scaled down to the laser wavelength-size. Each cell in these structures has an opening from the side. Special Electro-Optical device controllably sweeps focused laser spot along these openings in accordance with instant position of accelerated micro-bunch inside the structure. This arrangement reduces the illuminating...

Coherent bremsstrahlung (CBS) is a specified type of radiation at colliders with short bunches. In the present paper we calculate the main characteristics of CBS for the BEPC collider. At this collider dN γ ∼ 3 · 10 8 dE γ /E γ photons of CBS will be emitted for a single collision of the beams in the energy range E γ < ∼ 240 eV. It seems that CBS can be a potential tool for optimizing collision...

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...

In the Fermilab Main Injector (MI) we are planning to double the bunch intensity from its design value by slip stacking. The accelerator consists of 18 rf cavities which operate at a harmonic number of 588. These cavities are known to have many higher ordered resonances. Longitudinal coupled-bunch instability induced by excitation of the rf cavities may be an important issue to be addressed in ...