Low-Cost Closed-Loop Cryogenic Cooler for High Power Optics

For high-brightness focused light sources, extremely sensitive optics are employed to provide high quality, highly stable, and accurate beamlines. Precision mirrors and crystals used in these beamlines must maintain their dimensions to nanometer tolerances under demanding operating conditions including high thermal loading. Existing systems for maintaining cryogenic conditions within precision optics hardware are not optimally suited for long-term cost-effective use at conditions of > 250 W, 125 K. To address this need, Creare proposes to develop a low-cost, highly reliable, mixed gas Joule-Thomson (J-T) cooler, capable of high-heat-flux dissipation at cryogenic temperatures. Creare’s advanced J-T cycle makes use of a commercially available gas compressor operating at ambient temperature, a compact high effectiveness recuperator, and a two-phase evaporative thermal load interface—and no dynamic hardware in the cryogenic temperature range. These features afford the system overall low cost and simplicity. The highly innovative thermal load interface features an integral sintered microporous throttle plate which both serves as the J-T orifice and provides an effective fin structure to the thermal interface, which is then directly impinged by two-phase cryogenic refrigerant. In Phase I, we proved the feasibility of our approach by conducting system-level trades, designing and assembling a sub-scale cooler and demonstrating its operation below 125 K, and then developing a full-scale cooler design for Phase II build. In Phase II, we will work with DOE and commercialization partners to further optimize the design for cost, fabricate a prototype cooler at full-scale, demonstrate its performance in a representative environment, and deliver it to DOE for further performance evaluation. Aside from the longer-term research benefits, we envision that the proposed cryocooler technology with minor modifications can be directly integrated into several commercial industries and processes. Among the sectors poised to benefit the most is semiconductor manufacturing. Aerospace, defense, and healthcare sectors are also set to directly benefit from application of the proposed technology, in particular by enhanced image resolution allowed by this technology.