Electro-optical Designment And Experiment Research On Large Format X-Ray Streak Tube

During the laser inertial confinement fusion(ICF)experiments,X-ray streak camera could provide high space-time resolution,therefore is very important in the diagnosis of equipme nt.The duration of the laser fusion is associated with the pulse width of the used laser output,therefore the maximum duration of the laser fusion is about nanosecond at least.As the laser drive energy is ever-increasing and the experiment device is more and more sophisticated,along with the growing costs of target hitting,required that X-ray streak camera should obtain as much information as possible in every shooting process.The current knowned streak camera with the most diameter of photocathode is about 50 mm,which could provide 1000 line pairs the amount of information,while the domestic existing streak camera with the biggest cathode to 30 mm in diameter,and the spatial resolution of 15 lp/mm,could only provide nearly 450 cell the amount of information,which could not satisfied the experiment demands of distinguishing 800 cell the amount of information.Aims to meet the high requirement which Inertial Confinement Fusion has put forward to streak camera,through deep research,we proposed some effective approach.1.For improving the amount of space information captured by steak tube,we design and develop a electroptical structure consist of multi-axisymmetric cylindrical pole with different diameter for large format steak tube.Through the optimized design,the effective length of cathode is 50 mm,and the anode voltage is12 kv,with the magnification 1.35.For alliveating the effect by field cureved,a spherical phosphor with the curvature radius of 64 mm was applied.Test result of the sample tube shows that the static of center is 30 lp/mm(the contrast 30%),off-axis 16 mm in static extremity space resolution is 25 lp/mm(18 lp/mm with contrast 21%).Dynamice test shows that the dynamic spatial resolution in the center of cathode is 22 lp/mm(contrast of 10% for 20 lp/mm),and the time resolution is 3.3 ps,dynamic range of up to 2000:1.2.In order to expand the imaging area under the premise of further reducing the effects of field curves,the concentric sphere electrostatic focusing system was used to be the prototype tube.Through analysising the characteristics field distribution of concentric sphere system,we design a approximate concentric sphere electrostatic electroptica l structure consist of multi-pole for large format streak tube,with the field distribution is similar to prototype.Numerical simulation results show that the the electroptical structure with the 50 mm length cathode can obtain excel ent imaging performance,and the magnification is about 1.The electron trajectory tracking results show that the the influe nce caused by the field curves and other aberrations on the image shape is alleviated effective ly.While using a planar phosphor screen,it proved that the spatial resolution within the scope of the whole length of the cathode can be up to 30 lp/mm,which could provide at least 1500 lines pairs of spatial resolution.