Speaker
Description
Innovations to reduce afterpulsing, develop MCP-PMTs with 6 um microchannel plates for improved time resolution and rate capacity and a compact position sensitive MCP-PMT are in progress at Incom. A hydrophobic ALD film has been developed for use on top of an MgO secondary electron emission film. It is intended to reject water layers from air exposure, thereby reducing the load of adsorbed water load in the microchannels that leads to afterpulsing and photocathode degradation. Using a technique that combines aluminosilicate glass microchannel substrates with ALD films for resistance and secondary electron emission, Incom is reducing the diameter of the microchannels to 6 um. A 33 mm diameter size is in development, to be followed by scaleup to a 10 cm square size. A compact, 43 mm diameter MCP-PMT with a position sensitive, capacitively-coupled anode has been constructed to serve as both a test device for 6 um microchannel plates and as a routinely manufactured product. Finally, a square format 56 mm MCP-PMT is in development to have a scintillator with as a window. It is intended for use with PET medical imaging, where timing and position sensitivity may be degraded by a thick window. A barrier is required between the photocathode and scintillator to prevent unwanted diffusion and compositional changes. A thin fused silica window may also be used on this device.
