MICROSTRUCTURE PHOTOMULTIPLIER ASSEMBLY

摘要

The subject invention provides for a novel photomultiplier assembly, termed the Microstructure Photomultiplier Assembly (MPA), which enables the effective conversion of light signals (received at the front of the assembly) into readily-detectable electrical signals. The MPA comprises a photocathode (which converts light into electrons and which is located in front of or on the front surface of the assembly), followed by an electron-multiplying plate, or series of plates, each made from an insulating substrate which does not emit sufficient contaminants to poison the photocathode. Each plate is coated on the front and rear faces with a conductive layer. In addition, 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 (with non-conducting walls) and the number and geometry of these channels is designed to promote the efficient transfer and acceleration of electrons through the channel, under an applied voltage differential across the plate(s). The number of plates placed in series is determined by the desired degree of electron multiplication. At the exit of the last plate, an anode is located to collect the electrons and generate an electrical signal that can be read by conventional electronics. The anode can be a simple anode or can be a position-sensitive anode. The spacing between the photocathode, the electron-multiplying plates, and the anode is selected to promote the efficient transfer and acceleration of electrons across the assembly, as well as to promote the efficient production of secondary electrons. The photocathode, electron-multiplying plate(s) and anode are all contained within a vacuum enclosure.