The Extreme Ultraviolet Wave Band Research In Characteristics For The Microchannel Plate Photon Counting Position Sensitive Anode Imaging Detector

The plasmasphere around the Earth was the main way to study the geospatialmagnetosphere explosion by imaging the30.4nm radiation of He+. And themicrochannel plate photon counting imaging detector based on the wedge and stripeanode was developed to detect the30.4nm radiation in plasma layer of the earth.The detector consisted of three parts: the MCP stacks which was used to get thehigh gain electron cloud, the wedge and stripe anode which collected the electroncloud from the MCP stacks output, and the electron readout circuit which improvedand magnified the electron cloud signal. The experiment paid the most attention onthe characristics research such as dark noise, resolution and the gain of the detector.A preconditioning process encompassed vacuum baking and burn-in withultraviolet radiation. The MCP stacks was sustained350℃for18hours in theprocedure of bake-out. The burn-in procedure illuminating with ultraviolet radiation(253.7nm) from a deuterium lamp had been achieved when0.06Coulomb cm-2hadbeen extracted from the MCP stack output. Moreover, the experiment researched thefactors such as temperature and voltage which affected the characteristics of noise,resolution and gain as well. The experiment showed that the resolution and gainimproved as the voltage increased, however, when the voltage value was too large, the resolution reduced sharply and the image turned to be obscure, and the pluseheight distribution curve turned wider. There was a similar version of resolutionwhen the counting rate increased, but different MCP had different voltage of gainsaturation or peak counting rate. Therefore, suitable voltage or counting rate couldprovide better resolution. Besides, as the temperature rised, the dark noise countingrate increased. That is, the residual gases and the thermal emission were the majorsources of the dark noise, moreover, the cosmic rays, field emission, the radiation of40K in the microchannel glass increased the dark noise counting rate.The innovation of this paper was the preconditioning of MCPs. The equipmentof preconditioning experiment was built, and the MCP stacks which would be set inEUV detector outgassed by the preconditioning experiment and got a cross-referenceof the noise, resolution and gain characteristics. After the preconditioning the imagespatial resolution reached to125μm, the background events rate dropped to be0.53counts/s·cm~2, the PHD curve closed to Gauss distribution and turned to be morenarrow.