Accelerator Test Facility at Brookhaven National Laboratory (BNL ATF) operates with 5 MeV photocathode gun and 70 MeV linac for different range of experiments with a few picoseconds and a few micrometers emittance electron bunch. Many conducted experiments require beam with good spatial resolution and short length as well. NdYaG laser pulse turns to the electron bunch in the gun with space char...

A bunch compressor design for the Next Linear Collider (NLC) is described. The compressor reduces the bunch length by a factor of 40 in two stages. The first stage at 2 GeV consists of an rf section and a wiggler. The second stage at 10 GeV is formed by an arc, an rf section, and a chicane. The final bunch phase is insensitive to initial phase errors and to beam loading in the intermediate Sban...

This paper considers the process of Thomson scattering of coherent diffraction radiation (CDR) produced by the preceding electron bunch in the accelerator onto one of the subsequent bunches. It is shown that the yield of scattered hard photons is proportional to N(3)(e), where N(e) is the number of electrons per bunch. A geometry is chosen for the CDR generation and an expression is obtained fo...

In order to improve the luminosity, two crab cavities have been installed in KEKB HER and LER [1]. Since there is only one crab cavity in each ring, the crab cavity generates a horizontally titled bunch along the whole ring. The achieved specific luminosity with crabbed bunch is higher, but it is not as high as that from beam-beam simulation [2]. One of the suspicions is the electron cloud. The...

Ultrafast time-resolved electron diffraction based on a photocathode rf electron gun is being developed in Osaka University to reveal the hidden dynamics of intricate molecular and atomic processes in materials. The photocathode rf gun generates a femtosecond-bunch electron beam by femtosecond laser driving. The transverse emittance, bunch length and energy spread were measured. The growths of ...

An analytic theory of cumulative multibunch beam breakup in linear colliders is developed. Included is a linear variation of transverse focusing across the bunch train as might be applied, e.g., by chirping the radio frequency power sources or by using radio frequency quadrupole magnets. The focusing variation saturates the exponential growth of the beam breakup and establishes an algebraic dec...

A relativistic bunch moving in the vicinity of a dielectric slab excites Cerenkov radiation. The spectrum of this radiation depends on the dielectric coefficient, the energy of the bunch and its geometric shape. If the dielectric slab is active and the bunch excites the proper frequency, the wake will be amplified. In the framework of a linear theory we discuss the dependence the spatial growth...

We report on measurements of the bunch energy spectrum at the end of the SLAC linac. Using the spectra obtained for two different linac rf phases we obtain both the bunch induced voltage and the longitudinal distribution of the bunch. The measurement results are compared with theoretical predictions. In particular, the induced voltage is in good agreement with that obtained using the calculated...

We present a technique for the design and verification of efficient bunch-by-bunch controllers for damping longitudinal multibunch instabilities. The controllers attempt to optimize the use of available feedback amplifier power one of the most expensive components of a feedback system and define the limits of closed loop system performance. Our design technique alternates between analytic compu...