New Developments in Amorphous Silicon-Based Microchannel Plates

TL;DR: New developments in amorphous silicon-based microchannel plates have yielded high gain values and improved stability, paving the way for practical applications.

Abstract: Microchannel plates fabricated from hydrogenated amorphous silicon (AMCPs) are a promising alternative to conventional glass microchannel plates. Their main advantages lie in their flexible fabrication processes, allowing for adaptable channel shapes and the possibility of vertical integration with an electronic readout, a tunable resistivity of the main amorphous silicon layer, which allows a charge replenishment by a current flowing directly through the bulk material and possibly a lower cost of production. In this publication, we present further developments of the AMCP technology and its characterization. Small channel diameters down to $1.6~\mu \text{m}$ could be achieved, resulting in an aspect ratio of 25. This led to an increase of the electron multiplication gain to 1500 compared to the previous maximum of 100. The fabricated devices were characterized under both continuous and pulsed illumination. Additionally, the gain dynamics were measured over several minutes, showing increased gain stability with respect to previous devices. With the achieved gain values of this new generation of AMCPs, this technology can now be considered a viable option for real applications such as time-of-flight positron emission tomography or mass spectrometry.