Exploring the Limits in Ultrafast High Brightness Electron Beam Generation

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

Accelerators are important instruments for the advancement of scientific research, for their broad application in medicine and industry, and as a research area in their own right. Accelerators typically accelerate protons, antiprotons, electrons and positrons (anti-electrons). Powerful accelerators have lead to the discoveries of the Higgs Boson and the top quark, intermediate sized accelerators have been used as sources of x-rays to study properties of materials, and smaller machines are used to provide cancer therapy or for electron beam microscopy. A recent novel trend in accelerator and beam physics is the development of precise electron beams for diverse applications in the study of ultrafast structural dynamics, and as the drivers for Free Electron Lasers or laser-based accelerators. This award to UCLA aims to develop a new electron source capable of generating electron beams with an order of magnitude higher brightness than has been previously achievable using state-of-the-art radiofrequency photoinjectors. By pushing for lower beam charges, the design choices of a photoinjector cavity can be reevaluated, incorporating recent advances in cathode surface engineering and adopting different solutions for the beam dynamics. Technically, the development of a novel electron source with extreme beam parameters will have important impact on compact x-ray free-electron lasers and ultrafast electron diffraction and microscopy. These technologies have the prospect to provide real time atomic scale images of matter with the potential for profound impact in a variety of scientific fields such as condensed matter physics, chemistry, biology and material sciences. Educationally, the work with be intrinsically interdisciplinary and will provide full hands-on experience for students with a broad preparation in photoemission physics, laser and accelerator technology, and high brightness beam and beam diagnostic development. In the program as awarded, the UCLA group plans to study some of the most pressing unanswered questions in electron-source physics, such as the growth of the longitudinal emittance and uncorrelated energy spread and the limit in the cathode thermal emittance.