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Recently developed microchannel plates based on amorphous silicon offer potential advantages with respect to glass based ones. In this context, secondary electron emission at very low energies below 100 eV has been studied for relevant materials for these novel devices. The aim of this work was to quantify the low energy electron emission - secondary emission and elastic scattering - from amorphous silicon and alumina and the dependence of the emission energy distribution on the primary electron energy, which was previously unknown. Secondary emission and energy distribution were both modelled and measured using equipment particularly designed for this energy range. The effects of roughness, angle of incidence and surface composition were analysed. We show crossover energies as well as the angular dependence of electron emission from amorphous silicon and alumina, with a maximum experimental emission yield value of 2 and 2.8, respectively, at an incident angle of 75°. A parameterization for the energy dependence of the emission energy spectrum at low energies was derived. This extensive analysis is fundamental for a comprehensive understanding of the performance of amorphous silicon-based microchannel plate detectors. It provides a complete model for secondary electron emission for a detailed description of the detector operation. The present results thus set the basis for a simulation framework, which is an essential element to increase the performance of these detectors and enable further developments.

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 µm 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.

This contribution focuses on the fabrication and characterization of microchannel plates made of hydrogenated amorphous silicon (AMCPs). Flexible fabrication processes and the semi-conducting nature of amorphous silicon could give these detectors the advantage of superior temporal and spatial resolution over conventional lead glass based microchannel plates (MCPs). The current work focuses on the fabrication and characterization of high aspect ratio devices. The multiplication gain was measured under continuous illumination of UV light using a customized setup. Through optimization of the microengineering processes, devices with high aspect ratios up to 25 were realized which resulted in a multiplication factor of ~1500 for this new generation of AMCPs. This high gain, coupled with the AMCPs remarkable temporal and spatial resolution make them a promising alternative for various applications such as detectors for positron emission tomography.