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

Proliferation detection equipment requires deployment at remote, inaccessible sites and has to be able to operate over a rather wide temperature range.Scintillation light due to neutrons, gamma rays, or other indicators of nuclear material is typically detected with photon sensors based on photocathodes and microchannel?plate (MCP) amplifiers.Incom’s MCP technology uses an Atomic Layer Deposition (ALD) process to impart resistive and emissive properties to Glass Capillary Array (GCA) substrates.This offers the unique opportunity of tuning the thermo?electrical properties of the resistive layer, which is not possible with conventional MCPs.We propose to develop MCPs with optimized resistive coatings that can operate at ultra?high count rates in high background environments, and across broad temperature ranges.This development will afford photodetectors that operate stably over a broad temperature range, and to enable “lowpower” LAPPDs by using the low?TCR MCPs in low gain mode.In Phase I of this program we were able to show that for Incom’s baseline resistive material, Chem1, the TCR of ALD?GCA?MCPs can be adjusted by changing the material composition.We evaluated that the TCR of Chem1 can be significantly improved through ALD process optimization.We also developed a new tunable resistance material with an even lower TCR value of ?0.01 K?1.Qualification trials using GCA substrates are needed to further qualify this materials potential.In Phase II our work will be threefold; we will a) optimize our current tunable resistance material, Chem1, to achieve the lowest possible TCR for this material, b) qualify a new material developed in Phase I at Argonne for its applicability to MCPs, and c) continue the development of new materials.Potential applications that would benefit from stable, high?dynamic range ALD?GCA?MCPs include a wide variety of sensors for space flight instrumentation, time?of?flight mass spectrometers, PET scanners, Proton radiography, as well as high?temperature (T ? 200° C) PMTs for mining and oil prospecting applications.