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Abstract
New capabilities in nuclear nonproliferation industrial and medical applications as well as extending the reach of our understanding of the universe rely on advancing capabilities in particle acceleration. Enabling advanced X-ray methods demonstrated at large light sources to reach applications, for example, could reduce radiation dose while increasing specificity in methods for detecting nuclear material and for medical and industrial imaging. In the longer term, higher accelerating gradients could enable future particle colliders such as a multi-TeV e+e- collider to explore new physics regimes. Ultrashort pulse lasers enable resonant excitation of plasma waves, efficiently driving structures that can accelerate particles at rates of in the range of a GeV per centimeter to access such capabilities. At the GeV energy scale this enables novel compact photon sources including free electron lasers, and MeV photons from Thomson scattering. Guiding of such lasers in plasma structures formed by laser heating, capillary discharges and most recently by combining these two techniques has extended the depth of interaction from millimeter to tens of centimeter scale, enabling energies up to 7.8 GeV to be achieved. Experiments to combine two such stages at multi-GeV energies are being prepared. The same laser pulses are being used for acceleration of ions from solid targets using target sheath fields, and experiments are being planned to access more efficient ion acceleration regimes in the near future, supported by a new short focal length capability. While these BELLA Center experiments are proving the building blocks of a future plasma based high energy physics collider and photon sources, laser development holds the key to scaling to the repetition rate and precision required.
Bio:
Cameron G.R. Geddes is a Deputy Director of the BELLA center and a Senior Scientist at Lawrence Berkeley National Laboratory, focusing on study of laser driven plasma waves and their applications compact particle accelerators and photon sources. He is a Fellow of the APS DPP and a recipient of the Society's Dawson award, and of two LBNL Outstanding Performance awards. He has a project developing plasma based accelerators as compact sources of near-monochromatic MeV photons for nuclear material detection and characterization, and leads Center experiments in other areas. Previous positions include Thomson scattering measurement of driven waves in inertial confinement fusion laser-plasma interaction at LLNL, wave mixing in Omega laser experiments by Polymath Research, and small aspect Tokamak equilibria at the University of Wisconsin. He received the Ph.D. in 2005 at the University of California, Berkeley, supported by the Hertz Fellowship, where he received the Hertz and APS Rosenbluth dissertation awards for demonstration of a laser driven, plasma based electron accelerator producing mono-energetic beams. He received the B.A. degree from Swarthmore College in 1997, and received the APS Apker award and Swarthmore Elmore prize for work on Spheromak plasma magnetic equilibria.
https://lbnl.zoom.us/j/915928464