The progress of various high-brightness electron source technologies, specially laser based electron sources, such as photocathode RF gun, DC and pulsed photo-gun, and laser plasma electron source, will be reviewed. The physics processes of those sources to realize best performance are clarified according to three basic ideas. They are transverse space charge emittance compensation, space charg...

The photocathode radio-frequency (RF) gun is a powerful electron source to generate a high-brightness femtosecond electron beam with energies of 1~3 MeV. The RF gun based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe directly structural changes at the atomic scale with sub-100 fs temporal resolution. In this paper, we analyze the ...

The next generation light sources such as energy recovery linac (ERL) light sources and X-ray FEL oscillator require high brightness electron gun with megahertz repetition rate. We have developed a DC photoemission electron gun at JAEA for the Japanese ERL light source project. This DC gun employs a segmented insulator with guard rings to protect the insulator from field emission generated from...

A femtosecond electron bunch is essential for the observation of ultrafast phenomena. In order to improve the time resolution of pulse radiolysis and ultrafast electron diffraction (UED), that involve the use of an ultrashort electron bunch and ultrashort light, a femtosecond photocathode RF gun was investigated experimentally. The bunch length due to space-charge and RF effects in the gun was ...

Experimental nanotips have shown significant improvement in the resolution performance of a cold field emission scanning electron microscope (SEM). Nanotip electron sources are very sharp electron emitter tips used as a replacement for the conventional tungsten field emission (FE) electron sources. Nanotips offer higher brightness and smaller electron source size. An electron microscope equippe...

One of the 21 century scientific frontiers is to explore the molecule structure transition on the femtosecond time scale. X-ray free electron laser (XFEL) is one of the tools now under development for investigating femto-second structure transition. We are proposing an alternative technique – femto-second electron diffraction based on a photocathode RF gun. We will present a design of a kHz fem...

Several new approaches for producing high-current, short-duration pulses of electron beams were reviewed briefly in this paper. The paper presents mainly the simulation and analysis of a secondary emission microwave electron gun. The movement of electron in microwave electric field was simulated and the self-bunching process of the secondary emission electrons in the gun was also proved. Some f...

The manuscript reports the simulation of an electron gun with a view to optimizing the design of radio-frequency sources. The effects of eight parameters on the beam quality were studied and optimal choices were identified. It gives numerical beam qualities in common electrostatic triode gun, and the dependences on design parameters such as electrode geometries and bias voltages to these electr...

Consensus reached in the last few years that fourth generation light source will most likely be a X-ray or a UV coherent source based on single-pass high-gain free electron laser (FEL), such as Self Amplified Spontaneous Emission (SASE), or seeded high-gain harmonic -generation (HGHG) free electron lasers. High -gain (> 10) required for single-pass FEL puts great constrain on the quality of ele...

The X-Band Test Area (XTA) is being assembled in the NLCTA tunnel at SLAC to serve as a test facility for new RF guns. The first gun to be tested will be an upgraded version of the 5.6 cell, 200 MV/m peak field Xband gun designed at SLAC in 2003 for the Compton Scattering experiment run in ASTA [1]. This new version includes some features implemented in 2006 on the LCLS gun such as racetrack co...