High-brightness electron sources are of fundamental interest for particle accelerators and modern free electron lasers. Inspired by the micro-structure of field emitter arrays [1,2] we report on a new type of metallic photo-cathode consisting of thousands of Nb3Sn micro-columns. With this metallic photocathode we could demonstrate quantum efficiencies up to 0.5% under stable operation [3,4]. Pr...

The problems encountered with the interpretation of martensite and the various forms of bainite that are found in high strength steel weld metals have been addressed. Field emission gun scanning electron microscopy was found to overcome resolution difficulties often met with light optical microscopy and conventional scanning electron microscopy. The various microstructural constituents were cha...

L-band normal conducting RF guns operating at long pulse mode and high gradient are installed the European X-ray Free-Electron Laser (European XFEL) Free-electron LASer in Hamburg (FLASH) as brightness electron sources. The dark current generated from gun may cause severe issues, such component activation, superconducting radio frequency (SRF) cavity quench undulator degradation. is one of para...

This paper describes the capabilities and limitations of computer programs used to design electron guns and similarly space-charge limited transport systems. Examples of computer generated plots from several different types of gun problems are included.

The BNL Laser-Electron Accelerator Facility (LEAF) uses a laser-pulsed photocathode, radio-frequency electron gun to generate ù7 ps pulses of 8.7 MeV electrons for pulse radiolysis experiments. The compact and operationally simple accelerator system includes synchronized laser pulses that can be used to probe or excite the electron-pulsed samples to examine the dynamics and reactivity of chemic...

The Linac Coherent Light Source (LCLS) is a SASE free electron laser using the last 1/3 of the SLAC two mile linac to produce 1.5 to 15 angstrom x-rays in a 100 meter long undulator for use in a variety of x-ray science experiments. In order to satisfy the demanding electron beam requirements, a new 135 MeV photo-injector will be built in an existing, off-axis vault at the 2/3 point of the main...

Rf electron guns require an external magnetic field focussing to produce a low emittance electron beam. A dc magnetic field focuses electrons in the beam already inside the cavity as they leave the photocathode. In superconducting rf guns (srf) the possibility of external magnetic focussing is quite limited. In this paper we investigate an effect of rf focussing in the first half cell of a 3+1/...