ATF Experiments Igor Pogorelsky

The BNL Accelerator Test Facility  Proposal-driven, advisory committee reviewed USER’S FACILITY for R&D in Accelerator and Beam Physics.  High-brightness e beams synchronized to high-power lasers.  The purpose: developing long-term approach to new methods of acceleration, generation of radiation and associated subjects.  Serving National Labs, universities and industry.

ATF Experiment Hall Our Core Capabilities High brightness laser cathode e-gun (1 nC, 1 mm mrad, 10 ps) 70 MeV linac (120 MeV, 300 fs upgrade planned) 30 GW 150 ps CO 2 laser (soon 3 terawatt, 10 ps) Fully instrumented experiment hall with 3 beam lines >1000 hours beam time delivered annually

Nonlinear-Compton Scattering Smith-Purcell Radiation Photocathode R&D Beam Position Monitors for Linear Colliders Stimulated Dielectric Wakefield Accelerator Staged Electron Laser Accelerator (STELLA) Compton Scattering of ps Electron and CO 2 Beams Ultra-fast Optical Detection of Charged particles Laser Driven Cyclotron Autoresonance Accelerator (LACARA) A SASE-Free Electron Laser Experiment, (VISA) Electron Beam Compression Based Physics at the ATF Structure-based Laser Driven Acceleration in a Vacuum Optical Diffraction-Transition Radiation Interferometry Diagnostics Particle Acceleration by Stimulated Emission of Radiation 14 currently active experiments:

Illustrated by Thompson scattering experiment – presently the brightest Thomson x-ray source. Benefits of using long-wavelength ( =10  m) CO 2 laser: Combines advantages of high-quality conventional RF accelerators and high-gradient optical accelerators with  =~1  m favorable phasing structure scaling. Illustrated by STELLA - the first two-stage laser accelerator Ponderomotive potential that controls x-ray production, plasma wake generation and other strong-field phenomena is proportional to 2.

High-Pressure CO 2 Amplifiers

ATF CO 2 Laser System

Bandwidth-limited amplification of picosecond CO 2 laser pulses

Simulations of electron beam bunching initial uniform energy distributionbunching after drift sinusoidal energy modulation after buncher 50% of electrons within FWHM=0.63  m

STELLA - Staged Electron Laser Acceleration

Inverse Free Electron Laser (IFEL) Physics  Use periodic magnet array (wiggler/undulator) to cause electron trajectory to oscillate while traveling through array  Net energy exchange between electrons and laser beam possible if resonance condition is satisfied where L = laser wavelength w = wiggler wavelength  = Lorentz factor K = eB o w /2  mc B o = peak magnetic field  Higher energy exchange possible using tapered wiggler/undulator

STELLA - Staged Electron Laser Acceleration

STELLA II

ATF Thomson Scattering Experiment

Results from Thomson Scattering Experiment Signal on detector is equivalent to 2.5x10 7 photons/pulse. Low energy x-rays are blocked by Be window and air. 15% of total generated photons reach the detector. 1.7x10 8 photons/pulse produced at the interaction point. Since pulse duration of the x-ray signal is equal to the electron bunch length (3.5 ps), estimated peak x-ray intensity is 5x10 19 photons/second.

The total number of  -rays generated in 200 collision points is photons/bunch. W target of 1.75 mm thickness generates polarized positrons/bunch. Proposed polarized positron source for Japan Linear Collider

From Free Space … Laser pulse duration shall match the interaction length that is defined by Rayleigh distance in free space. ….to Plasma Channel We brake the laser pulse duration constraint by extending the interaction length in a plasma channel.

r  nene optical guide Plasma channel formation in the capillary discharge

laser beam at the focal point 17 mm downstream from the focus in the free space at the exit from the 17 mm plasma discharge Channeling of CO 2 laser in capillary discharge

Nuclear Physics Condensed Matter High Energy Phys. High Energy & Nuclear Physics Directorate Physics Directory RIKEN / BNL Research Center Experiments by name and number Department Committees Seminars & Colloquia Conference Rooms Safety, Environment & Training Cybersecurity Info NUHEP Accounts PhysNet Computing and Desk Top Resources Affirmative Action Committee & Fellowship Image above: Plasma wakefields were generated at the Accelerator Test Facility by a relativistic electron bunch interacting with a plasma in a capillary tube. Details...Details... The Physics Department carries out research in experimental and theoretical high energy, nuclear and condensed matter physics Samuel Aronson, Chair Howard Gordon, Associate Chair Peter Johnson, Acting Associate Chair Organizational Chart Last update on: by S. Parrish.S. Parrish Anouncements/Meetin gs LoopFest II Brookhaven National Lab May , 2003 CIPANP th Conference on the Intersections of Particles and Nuclear Physics Grand Hyatt Hotel - NYC May , 2003 Series of Colloquia on Astrophysics and Cosmology Series of Colloquia on Astrophysics and Cosmology (MS Word FIle) Physics 2002 APS Fellows Physics 2002 APS Fellows (MS Word File) APS Fellowship Program RHIC Detector Advisory Committee RHIC Detector Advisory Committee

Plasma Wakefield Generation and Probing 45 MeV 1 nC electron beam excites plasma wave that produces electron acceleration and focusing.

Nonlinear-Compton Scattering Smith-Purcell Radiation Photocathode R&D Beam Position Monitors for Linear Colliders Stimulated Dielectric Wakefield Accelerator Staged Electron Laser Accelerator (STELLA) Compton Scattering of ps Electron and CO 2 Beams Ultra-fast Optical Detection of Charged particles Laser Driven Cyclotron Autoresonance Accelerator (LACARA) A SASE-Free Electron Laser Experiment, (VISA) Electron Beam Compression Based Physics at the ATF Structure-based Laser Driven Acceleration in a Vacuum Optical Diffraction-Transition Radiation Interferometry Diagnostics Particle Acceleration by Stimulated Emission of Radiation 12 more currently active experiments: