Large Dynamic Range Streak Like Tube Theoretical And Experimental Research

Dynamic range and time resolution are ambivalent in the streak image tube. Therefore a large dynamic range streak image tube has to be developed for the ICF research, which possess of quite high time resolution and large dynamic range.Several factors influencing the temporal response of streak tube, including the time dispersion due to the initial energy of photoelectron and dispersion of transit time of electron in focusing region, and those influencing the dynamic range of the streak tube, such as influence of space charge effect on photo-electron emission, transition process of photo-electron emission and the current saturation effect of phosphor screen, are analyzed. The design method evaluated on Time-Spatial MTF, calculated in the means of Monte-Carlo, is confirmed.On the basis of analyzing space charge effect, which is the common physical mechanism influencing time resolution and dynamic range, plane focusing electron-optical column lens is adopted, instead of rotational symmetrical electron-optical system. Reducing the axial dimension of focusing region and increasing voltage reduce the photoelectrons transit time. Therefore, the space charge effect can be restrained greatly, and the dynamic range of the tube is improved.The feature of the streak tube is miniaturization and compact. The parameters of the tube are focusing region of 65mm in the total length of 190mm, deflection sensitivity being as large as 40mm/kV, small time distortion, less than 300fs as the theoretical time resolution and static spatial resolution of 601p/mm.On the basis of the electron design above the large dynamic range streak tube is manufactured after we achieve success in the structural design and machining. Some static specification has been acquired by static experiments.