SBIR-STTR Award

The gradients associated with plasma-based accelerators are much larger than those for conventional accelerators. Therefore, higher energies are possible at a much lower cost than would be incurred using conventional technology. However, single stage plasma accelerators are generally only a few centimeters long, and multiple stages would be required in the design of plasma-based accelerators. This project will design and build a two-stage laser wakefield accelerator. The accelerating structure will be a plasma wave driven in a plasma channel by a short pulse laser. Two such channels with different densities will be produced in two capillary discharges. The two channels will be optically coupled using a plasma lens. During Phase I, the two-stage structure will be designed. Analysis and simulations will be employed to study issues of injection, guiding, acceleration, and diagnostics.

Commercial Applications and Other Benefits as described by the awardee:
The plasma lens should have commercial application as an element for the control and manipulation of high intensity laser pulses. The accelerator itself could find applications in, e.g., free electron sources of radiation

The gradients associated with plasma-based accelerators, such as a laser wakefield accelerator, are much larger than those in conventional accelerators.  To realize the potential of a laser wakefield accelerator and obtain high-energy electrons, it is necessary to (1) provide a means to guide the laser beam, and (2) stage the accelerating module to reduce dephasing.  This project will address both issues and perform experiments to achieve electron energies approaching 1 GeV.  Gas-filled capillary discharges will be employed to optically guide the laser beam over extended distances.  To mitigate dephasing in a laser wakefield accelerator, two or more capillaries, placed end-to-end with increasing plasma density, will be configured.  In Phase I, design parameters were obtained using scaling models and reduced analytical models.  Particle-in-cell simulations, employing massively-parallel, fully-electromagnetic codes, were then employed to refine the design.  Phase II will conduct experiments that employ a 10 Hz, 10 TW, and 50 fs Ti-sapphire laser beam.  A fraction of the beam will be extracted and utilized for the injector, and the rest will be used to drive a wakefield in a plasma channel made up of several capillaries, each of which has a uniform density along the direction of propagation.  Accelerated electrons will be detected and analyzed by employing dipole magnets, âerenkov radiation, and nuclear activation.  Commercial Applications and Other Benefits as described by awardee:  High gradient, compact accelerators would have applications in free-electron sources of radiation for medical diagnostics and remediation.  Plasma channels should have applications in guiding, transporting, and shaping intense laser bea