Contamination-Free, Lightweight, Helium-Rubidium Vapor Circulator for DPAL Systems

Diode-Pumped Alkali Laser (DPAL) systems have great potential for missile defense and other applications. These systems require a uniform, steady, flowing mixture of helium and rubidium vapor at elevated pressure and temperature. Significant challenges exist because rubidium is a very reactive material. Our team has developed a contamination-free, hermetic circulator based on gas-bearing turbomachines we produced previously for space-based applications. Specific benefits: low mass, compact volume, zero maintenance, high reliability, and long life. The approach is also modular and scalable with current technology appropriate for a broad range of flow rates. Our team is well-suited to succeed: We have a long history developing advanced thermodynamic systems for challenging aerospace applications, core technology elements are mature from prior work, we have access to high-level laser expertise to ensure design details are relevant for DPAL systems, and we have extensive experience with alkali metal reactivity and compatibility. We optimized design trades, completed a preliminary design, and conducted rubidium vapor tests during the Phase I project. We fabricated and tested a prototype circulation system during an initial Phase II project. We now plan to scale the technology up in size to support future MDA DPAL systems during a Second Phase II project. Approved for Public Release | 18-MDA-9817 (23 Oct 18)