Used In Icf Diagnosis High Space-time Resolution Of Key Techniques Of Imaging

The gated MCP framing technology has been the core diagnostic technology inthe inertial confinement fusion (ICF) experiments. It plays a very important role inthe fields of hohlraum physics, X-ray radiation transportation, and so on. Because ofthis technology supporting on accurate image collecting, it is only technology whichcan be used to capture2D pictures of ultra-fast phenomena with high temporal andspatial resolution. The framing camera using this technology plays an important rolein ICF research and reflects a country’s capability on manufacturing hightechnological equipment. Because foreign equipments in this area are embargoed onchina, developing framing camera with high spatial and temporal resolution has agreat significant on ICF research.The basic characteristics of the high performance framing camera is its hightemporal resolution, high spatial resolution, high sensitivity, ease of use and highreliability. With the ICF research continuously, the performance of the framingcamera needs to be improved. This paper is based on several key technologys arestudied.1． For improving the gain and uniformity of the framing system, thephotocathode structure and coating craft was qualitatively analyzed based on theprinciple of optical coating film and uniformity. By improved and optimizedtechniques I found the method to increase the conversion efficiency of the cathodeand decrease the loss of the pulse transmission and then the sensitivity and cathodeuniformity were improved. It is helpful to meet the need of precision for ICF.2．The dissertation systemically studied the factor of spatial resolution offraming system based on boundary element method and Monte Carlo method andtheorized the model of two-electrode, three–electrode, the curve VMCP-VSCREEN-MTF.It provided a theoretical guide for improvement spatial resolution. It is alsoworthwhile to mention that based on this conclusion new screen with high spatialresolution was designed. Production process of this screen is simple and reliable. Itwas patented and had been used in ICF research.3．For improving the time resolution, two systems were researched anddeveloped based on the principle that the thinner MCP gated by one pulse and twoMCPs gated with two pulses. Its temporal resolution was improved from60ps to 35-45ps and reached the international advanced level. The method of the alignmenthole was invented based on optical interference and diffraction. Poor spatialresolution and image nonuniformity existed in normal two MCPs were averted andthe performance of the two MCPs camera was improved.4．Two specified cameras were designed using the result of1and2according tothe requirements of the ICF research.A. Large image framing system: for increasing spatial resolution andgetting large image in ICF research, the framing camera with large screen wasdeveloped. The diameter of the screen increased from56mm to106mm. Each areafor acquiring image increased from6mm×6mm to20mm×40mm, and Z-Pinchimage was successfully acquired when experiment on QG-I ccelerator.B. The intelligentized framing system: embedded framing camera wasdesigned according to SG-III closed to completion. Cutting craft was researched forgetting rectangular MCP framing tube. Pinhole imaging system is designed based onpinhole imaging principle. Experimental image on SG-Ⅲ had acquired through thisnew type camera.The main innovation of the paper lies in:(1). From optical film perspective, structure of the photocathode effecting onthe characteristics of the gain and uniformity of tube was qualitatively analyzed, thedynamic characteristic of the tube was improved by optimized production processes.(2). Based on the theory mode of main factors that effect the spatial resolutionand the development of new type screen, it is indicated the next direction forimproving the spatial resolution of framing camera.(3).By innovation design of structure, the time resolution reached theinternational advanced level of35ps; and big image framing system has beendeveloped.