Corrugated Feedhorn Arrays by Additive Manufacturing

The Department of Energy’s Office of Science seeks to reduce cost and improve high energy physics particle and radiation detector sensitivity and manufacturability via the flexibility and reproducibility of additive manufacturing to produce complex detector components. Cosmic microwave background measurements characterize the temperature and polarization anisotropies of the universe. A critical component of cosmic microwave background observation is the feedhorn antenna, used to convey and focus waves onto a transitionedgesensor bolometer operating at cryogenic temperatures. Current materials and manufacturing processes for feedhorn arrays have poor thermal expansion coefficient match to the Si detector, and it is not possible to manufacture high frequency array structures due to the softness of the materials and tight tolerances required for detector operation. The challenges of manufacturing system complexity, and anticipated ~500 cosmic microwave background detector arrays, set the need. The objective is to enable manufacturing of high frequency feedhorn arrays, while reducing manufacturing costs, used in cosmic microwave background stage4 high energy physics experiments by developing and demonstrating the potential of combined additive manufacturing and electrofinishing approaches. In Phase I, the manufacturing processes to fabricate feedhorn arrays were developed. Specifically, only two distinct manufacturing operations were required: 1 additive manufacturing build development, and 2 final electrofinishing shaping and polishing of feedhorns to targeted design dimensions set by the cosmic microwave background detector community. The cost effectiveness of the approach will be realized through reduced material waste, higher resolution products, and enhanced detector sensitivity.Phase II will refine the additive manufacturing and electrochemical finishing approaches and enable the production of feedhorn subarrays 36 feedhorns that can be evaluated for their performance within a cosmic microwave background radiation environment. Specifically, the manufactured feedhorn subarrays for stage 4 cosmic microwave background detectors will be tested via metrology and beam mapping at subK temperatures and validated for transition to full scale 432 feedhorn arrays produced in a Phase IIB/III program. Phase III will transition and integrate the manufacturing process into full stage 4 cosmic microwave background detectors detector modules. Commercial applications for the formation and finishing of refractory materials via the combined additive manufacturing and electrochemical surface finishing processes could find applications within aerospace, medical, automotive, or industrial power systems.