Study On Photon Reflection Characteristics Of Input Surface Of Microchannel Plate

The low-light level night-vision technology is very important to enhance the night combat capability of modern war.Low light image intensifier is the core components of low-light level night-vision technology,which consists of photoelectric cathode,electron multiplier and fluorescent screen.Second,third and fourth low-light-level image intensifier,which realize electron multiplication through the microchannel plate,greatly improve its overall performance.However,in practice,due to photon transmitted from the photocathode has a certain reflection on input surface of microchannel plate,which produces photon scattering noise and reduces SNR.After reviewing literature,the author found that there is less research on this aspect in related industries at home and abroad.The aim of this paper is to reduce the reflectivity of the input surface of microchannel plate in the process,so as to provide a theoretical basis for reducing reflectivity of input surface of microchannel plate and thereby reducing photon scattering noise.This paper studied the relationships between photon reflection characteristics of input surface of microchannel plate and incident spectral wavelength,size of microchannel wire diameter and whether the input end face is steamed and coated with ionic feedback membrane.In theory,the maxwell's equations could be used to figure out optical constants and wavelengths of metallic films,relationship between conductivity and other factors,which explained the relationship between the reflection characteristics of the input surface of the microchannel plate and wavelength.It was concluded that reflectance of the input surface will be reduced after application of anti-ionic feedback membrane.The opening area ratio was determined by the diameter of the microchannel plate.The photon scattering noise was a part of the additional noise,which was proportional to the open area ratio.So the input reflectance of the microchannel plate was proportional to the size of open area ratio.The sample size of the experiment was 6?m?8?m?10?m,and the reflectance was tested by UV-3600 spectrophotometer at 200nm-800 nm band.The results showed that the reflectance of the sample of 6?m microchannel plate increased linearly in 200nm-500 nm band,and then stabilized from about 10% to 17%.Compared the test results of 8?m and 6?m samples,the reflectivity of 8?m samples with large opening area was small,which was not totally consistent with the theoretical analysis of "proportional relationship between reflectivity and open area",this paper analysed the cause of error.And the reflectance of the coating was reduced by about 2.5% after application of 10?m micro-channel plate sample MCP.On the basis of the experiment test,we made the analysis of the data curve fitting,worked out the function relation between reflectivity and wavelength of each sample.To sum up,reflection of the microchannel plate on other bands could be obtained through the cathode transmission,so as to make further analysis about photon scattering noise.