Wim Pieter Leemans

Transition of the BELLA PW laser system towards a collaborative research facility in laser plasma science

The advancement of Laser-Plasma Accelerators (LPA) requires systematic studies with ever increasing precision and reproducibility. A key component of such a research endeavor is a facility that provides reliable, well characterized laser sources, flexible target systems, and comprehensive diagnostics of the laser pulses, the interaction region, and the produced electron beams. The Berkeley Lab Laser Accelerator (BELLA), a PW laser facility, now routinely provides high quality focused laser pulses for high precision experiments. A description of the commissioning process, the layout of the laser systems, the major components of the laser and radiation protection systems, and a summary of early results are given. Further scientific plans and highlights of operational experience that serve as the basis for transition to a collaborative research facility in high-peak power laser-plasma interaction research are reviewed.The advancement of Laser-Plasma Accelerators (LPA) requires systematic studies with ever increasing precision and reproducibility. A key component of such a research endeavor is a facility that provides reliable, well characterized laser sources, flexible target systems, and comprehensive diagnostics of the laser pulses, the interaction region, and the produced electron beams. The Berkeley Lab Laser Accelerator (BELLA), a PW laser facility, now routinely provides high quality focused laser pulses for high precision experiments. A description of the commissioning process, the layout of the laser systems, the major components of the laser and radiation protection systems, and a summary of early results are given. Further scientific plans and highlights of operational experience that serve as the basis for transition to a collaborative research facility in high-peak power laser-plasma interaction research are reviewed.

Narrow bandwidth Thomson photon source and diagnostic development using laser-plasma accelerators

Compact, high-quality photon sources at MeV energies are being developed based on Laser-Plasma Accelerators (LPAs), and these sources at the same time provide precision diagnostics of beam evolution to support LPA development. We review design of experiments and laser capabilities to realize a photon source, integrating LPA acceleration for compactness, control of scattering to increase photon flux, and electron deceleration to mitigate beam dump size. These experiments are developing a compact photon source system with the potential to enable new monoenergetic photon applications currently restricted by source size, including nuclear nonproliferation. Diagnostic use of the energy-angle spectra of Thomson scattered photons is presented to support development of LPAs to meet the needs of advanced high yield/low-energy-spread photon sources and future high energy physics colliders.

Two-color laser high-harmonic generation in cavitated plasma wakefields

A method is proposed for producing coherent x-rays via high-harmonic generation using a laser interacting with highly-stripped ions in cavitated plasma wakefields. Two laser pulses of different colors are employed: a long-wavelength pulse for cavitation and a short-wavelength pulse for harmonic generation. This method enables efficient laser harmonic generation in the sub-nm wavelength regime.

Design of a Compact ion Beam Transport System for the BELLA Ion Accelerator

The Berkeley Lab Laser Accelerator (BELLA) Center hosts a Ti:sapphire CPA laser providing laser pulses at petawatt-level peak power with a repetition rate of 1 Hz. High irradiances of 1022 W/cm2 can be achieved with a short focal length beamline when the laser is focused to a spot of w0<5 m. Under this condition, theoretical and particle-in-cell (PIC) simulations have shown that protons and helium ions at energies up to several hundred MeV/u can be expected from the interaction between BELLA laser pulses and different targets. Ion beams of high energies, low energy spread and with high controllability and stability have numerous potential applications. A preliminary ion optics design is presented to collect, transport, and focus the ions generated from the laserdriven ion accelerator.

Staged laser plasma accelerators

We present current results on staged electron acceleration in the LOASIS program at the Lawrence Berkeley National Laboratory. The goal is to experimentally demonstrate laser driven electron acceleration in two stages, where each stage is driven by a separate laser pulse. This technology could provide the key to built compact laser driven accelerators which could potentially reach up to TeV in electron energy.

THE 13TH ADVANCED ACCELERATOR CONCEPTS WORKSHOP (AAC'8)

The Thirteenth Workshop on Advanced Accelerator Concepts (AAC) was held from July 27 to August 2, 2008 at the Chaminade Conference Center in Santa Cruz, California, USA, organized by the Lawrence Berkeley National Laboratory and the University of California at Berkeley. There were unprecedented levels of interest in the 2008 AAC Workshop, and participation was by invitation, with 215 workshop attendees, including 58 students. Reflecting the world-wide growth of the advanced accelerator community, there was significant international participation, with participants from twelve countries attending.

Asymmetric Pulse Shapes in Grating-Based CPA Compressors and Optimal Electron Acceleration in Plasmas

The temporal shape (skew) of the envelope function of 50–200 ferntosecond Ti:sapphire laser pulses has been controlled by fine-tuning the higher-order spectral phase coefficients to optimize the electron yield of a self-modulated plasma wake-field accelerator.