This effort involves the development of an electron beam transmission window for use in a KrF laser system in support of direct-drive inertial fusion energy. This project includes the study, design, and production of thin "hibachi" windows fabricated from silicon wafers (~ 100 micron thick) coated with a ~ 1.2 micron thick nano-crystalline diamond coating. The effort in FY05 involved the development of a 24-window hibachi prototype with edge cooling (See Figure).

This design incorporates an aluminum frame with internal channels for active cooling. Bench testing of the silicon windows during FY05 indicated that they can withstand differential pressure and pulsed pressure cycling consistent with those required for the laser to work in an extended 5-Hz rep rate. Work on the window development is expected to optimize mounting and cooling configurations. The fabrication of this hibachi prototype will focus on a design that supports an economical configuration and that provides ease for changing-out individual windows while maintaining the frame parameters and operational considerations.

The 24 round objects are the silicon wafers. The copper tubes provide edge cooling so when the electrons pass through the windows, heat can be removed from the edges of the frame.