discovered effect of parasitic spontaneous electron emission. Some output current, which is not a conductivity current, exists even in the absence of exiting input electron beam. That is, the plate is multiplying its own electrons spontaneously emitted from channel walls. This effect exists in all three types of MCP coatings, and is most intensive in case of NiO-MgO coating, probably due to the biggest coefficient of secondary electron emission of that coating.
The effect of spontaneous electron emission is probably caused by nonflat surface of channel walls leading to significant fluctuations of electric field. The mechanism of spontaneous electron emission is probably similar to Malter effect, which was studied in details exactly for anadic aluminum oxide, of which our MCP are made.
Nonflatness of the surface of channel walls is due to currently used procedure of microchannel structure formation – directional etching of anodic alumina already having natural pores. Such a procedure allows to form microchannel structures with optimal for research purposes ratio of channel length to its width – from 10 to 20. Howerver the channel walls produced by this procedure have very complex relief created by sharp partually etched remnants of pores. Currently we are looking for solution of this problem.
Our research proves that anodic aluminum oxide technology is a promising alternative to convinient lead glass MCP. It has potential to make MCP much cheaper, easier to produce, to increase spatial resolution of detectors on the base of MCP, to improve their ability to work in strong magnetic fields.
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