Resistive Coatings for High-performance, Low-background MCPs Operating Across Broad Temperature Ranges and at Cryogenic Temperatures

The Phase IIB SBIR titled “Resistive Coatings for High-performance, Low- background MCPs Operating Across Broad Temperature Ranges and at Cryogenic Temperatures” addresses the temperature stability of MCPs that serve as electron multipliers in detectors. MCPs have a negative TCR, meaning the resistance decreases at increasing temperatures which limits the operational range. At high temperatures, the reduced resistance can lead to higher current draw and thermal runaway. At low temperatures, the high resistance leads to long channel dead times, saturation effects and decreased gain. In contrast to conventional MCPs, Incom’s ALD-GCA-MCP technology allows to address the thermo-electric characteristics. ALD is used to grow a resistive and emissive film on a GCA, defining the resistance and secondary electron yield of the MCP, respectively. This functionalization process allows the substitution of lead glass with durable glasses that enabled the fabrication of LAPPDs. This Phase IIB Funding Opportunity continues R&D started under Phase I and II to develop ALD-GCA-MCP with a low TCR resistive layer. The baseline material was optimized to TCR values of conventional MCPs and the optimization is stepwise introduced to the production. However, two alternative resistive coatings were identified as low-TCR materials. The optimized molybdenum-based layer can achieve TCR values down to -0.01 K-1 which means a considerable improvement of the MCP temperature stability. In the proposed Phase IIB a comparative TCR and manufacturability study of the two materials will be conducted in the 1st year to prepare for the commercialization of the selected material in the 2nd year. Additional low-TCR candidates are studied at the beginning of the Phase IIB to possibly achieve even better TCR characteristics. The temperature stable MCP resistance will facilitate the operation in in-field application of the MCPs, which includes the detection of special nuclear materials. Currently, the operational voltage has to be constantly adjusted to the changing conditions. Additional to non- proliferation the advances will have an impact in space flight missions and experimental physics. The improved applicability and performance of LAPPDs will also impact medical imaging products including detectors for positron emission tomography (PET scanning).