Supersonic Gas Jet Nozzle for Laser Wakefield Acceleration

Supersonic gas jet nozzles, used to generate the plasma part of a laser wakefield acceleration (LWFA) system, would enable the development of high-gradient advanced electron accelerators. However, the nozzle requires sharp boundaries between the jet stream and the surrounding vacuum. Such sharp boundaries are possible if the gas flows supersonically. The throat dimensions of the supersonic gas jet nozzle must have <10% error in order to ensure a uniform plasma density at the outlet of the nozzle. Due to the miniature size of the nozzle, achieving this high level of dimensional accuracy is a nontrivial fabrication problem. This project will develop fabrication technology for miniature supersonic gas jet nozzle profiles with the required dimensional accuracy. Phase I will build a prototype supersonic gas jet nozzle suitable for use in laser wakefield acceleration experiments. Existing diagnostics and software will be used to characterize the prototype. During Phase II, new capabilities will be incorporated into the nozzle design, including tapered density profiles. Commercial Applications and other Benefits as described by the awardee: In addition to the application to high energy physics, miniature, supersonic gas jet nozzles should have application to accelerators used in industrial processing, medicine, homeland defense, and high-energy physics.