The Microstructure Photomultiplier Assembly (MPA) enables the effective conversion of light signals (received at the front of the assembly) into readily-detectable electrical signals. The MPA comprises a photocathode, followed by an electron-multiplying plate(s) made from an insulating substrate which does not emit sufficient contaminants to poison the photocathode. Each plate is coated with a conductive layer. The front face of each plate is further coated with a layer of secondary electron-emissive material which, when struck by an incoming electron, can produce secondary electrons. Each plate is perforated with channels. The channels are designed to promote the efficient transfer and acceleration of electrons through the channels, under an applied voltage differential across the plate(s). An anode (pixelated or non-pixelated) at the end of the last plate collects the electrons and generates an electrical signal. The MPA is contained within a vacuum enclosure.