We developed an UV Solar Blind image intensifiers with 18mm diameter semi-transparent cesium telluride photocathodes in a close proximity focus microchannel plates (MCP) tube. Cs-Te photocathodes have been evaporated onto quartz substrates at an elevated temperature to achieve quantum efficiency (QE) up to 34% and 70mA/W at 254nm, low dark current, low out of band response and high stability. New Cs-Te photocathodes have been fabricated for image intensifiers upgrade, which show fine image resolution, and less variation in high electron gain of the MCP. With these improvements, the image intensifier tube with new Cs-Te photocathodes will expand the application fields in low-light level UV Solar Blind detection.
Image intensifiers have been wildly used for military, law enforcement and commercial applications. Its small size, weight and power (SWaP) make it ideal for integration into different systems. Normally, the performance of image intensifiers is measured at room temperature, but it is expected to operate in vary temperature environments. Therefore, it is very important to know the variation of the image intensifiers performance with temperature. Here, we characterize the variation of intensifier photocathode, microchannel plates (MCPs) and phosphor screen over a large range of temperatures. The “bare” tube is connected to high voltage power supplies via cables. The power supplies and all measuring instruments are outside the chamber in order to avoid the influence of temperature. The result could be used to optimize and control the luminance gain of image intensifiers.
Micro-nano structure applied to photoelectric fields were made on high borosilicate glass by the MEMS process. This paper discussed the transmittance characteristics of micro-nanostructures by analyzing the transmittance of high borosilicate glass with different surface states and combining them with the theoretical analysis results. The transmittance of high borosilicate glass with different surface states was tested by an ultraviolet-visible spectrophotometer in the range of 400–850 nm. Through testing and comparison, it is found that the micro-nano structure makes the transmittance of high borosilicate glass obviously different in the test band. The average transmittance has been down 68%, and micro-nano structure can achieve anti-reflection in the specific band. Therefore, through matching the micro-nano structure with the photoelectric materials, the incident light could occur total reflection at the interface between the photoelectric materials and vacuum. Micro-nano structure can improve the utilization rate of light energy.
In this paper, the influence of the microchannel plates (MCP) opening area ratio (OAR) and secondary electron emission (SEE) coefficient of SEE layer on the noise factor of image intensifier tube have been studied. According to the experiment, the influence percentage of MCP OAR and SEE coefficient of MCP SEE layer on noise factor reduction has been obtained. A MgO SEE layer with SEE coefficient of 4.5 was coated on the MCP input side with an OAR of 68%. After being assembled as an image intensifier, the noise factor of MCP decreases from 1.638 to 1.096, and drop 33.0%, which laid a good foundation for improving the signal-to-noise ratio of image intensifier.
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