We present the results of numerical calculations of the effects of noise, slippage and superradiance in the UCLA infrared (IR) free electron laser (FEL). The experiment, which uses a high brightness electron beam produced by a photocathode RF gun and a 1.5 cm period planar undulator, will compare the FELevolution starting from noise to that starting from an input signal . Numerical studies indi...

The JAERI superconducting rf linac has been developed to produce a high-power infrared free-electron laser (FEL). So far, a stable kW-level laser output has been achieved with improvements of the electron gun, the optical resonator as well as the beam transport optics. For increasing FEL power, energy-recovery experiments are planned in the next phase of the FEL development. The lattice design ...

Once trained, the human brain is an excellent image processor; to replicate that skill for scanning electron microscope (SEM) image assessment demands considerable computing power. We have evaluated parallel computing for this purpose and developed an image processing tool for the automatic optimisation of electron gun alignment. The instrumental setup for this work was a Carl Zeiss 1430VP SEM ...

Recent years have witnessed rapid advances of MeV ultrafast electron diffraction (UED), in which high quality, ultrashort, MeV electron pulses from a photocathode RF gun are employed as probes for ultrafast structural dynamics. We’ve built a prototype MeV UED system at the Accelerator Laboratory of Tsinghua University, optimized the the electron pulse parameters as well as hardware performances...

We present a method to generate a flat (large horizontal to vertical emittance ratio) electron beam suitable for Linear Colliders. The concept is based on a round-beam rf-laser gun with finite solenoid field at the cathode together with a special beam optics adapter. Computer simulations of this new type of beam source show that the beam quality required for a Linear Collider may be obtainable ...

Low emittance sub-picosecond electron pulses are expected to be used in a wide field, such as free electron laser, laser acceleration, femtosecond X-ray generation by inverse Compton scattering, and pulse radiolysis, etc. In order to produce the low emittance sub-picosecond electron pulses, we are developing a compact racetrack microtron (RTM) with a new 5 MeV injection system adopting an laser...

A concept of double-decker electron beams, which have vertically different positions and time delay, was proposed for study of ultra-fast electron-induced reactions or phenomena by pulse radiolysis technique. One of the double-decker electron beams is used as a pump source, and another is converted to Cherenkov light and used as a probe light source. The double-decker electron beams were genera...

We review recent progress in the physics and technology of cold cathode electron emitters. The characteristics of emission from field emitter arrays, photocathodes, and ferroelectrics are presented, together with a summary of the understanding of the physics involved. The paper concludes with a description of L-band micropulse gun, based on secondary emission in an RF cavity. Emphasis is placed...

Collimation with hollow electron beams is a technique for halo removal in high-power hadron beams. The concept was tested experimentally at the Fermilab Tevatron collider using a hollow electron gun installed in one of the Tevatron electron lenses. Within the US LHC Accelerator Research Program and the European HiLumi LHC Design Study, we are investigating the applicability of this technique to...