X-ray framing imaging technique applied in laser fusion
The X-ray framing camera has high temporal resolution and two-dimensional spatial resolution,which is a significant ultrafast diagnostic device in the laser inertial confinement fusion(ICF)experiments.Such cameras are commonly used to obtain information such as implosion compressed dynamic images.In addition,this camera can also be applied for transient information detection in research,such as Z-pinch,X-ray laser,and synchrotron radiation.The temporal resolution of the traditional X-ray framing camera has been improved from 0.1 μs to 100 ps,as well as the achievement of the engineering and large frame size of the cameras.The microchannel plate(MCP)gated X-ray framing camera is a useful traditional X-ray framing camera,which has been developed over the last several decades and contains four basic components,the pinhole array,the MCP imager,the MCP gating pulse generator,and the charge-coupled device(CCD).The pinhole array is placed between the object and the framing camera,producing an array of X-ray images.Then,the X-ray images are converted into electron images and amplified at different times to obtain time-dependent information by using gated MCP.The electrons outputting from the MCP are accelerated onto a phosphor layer to produce intensified visible images of the incident X-ray images.Typically,the temporal resolution of such a camera is 35-100 ps,limited by the transit time and transit time spread of the electron multiplication process taking place in the MCP.With the deepening of the ICF research,the temporal resolution of the framing camera is required to be better than 30 ps.The electron beam dilation technology improves the temporal resolution to 5 ps.The dilation X-ray framing camera dilates the electron signal converted from the incoming X-ray signal.Then the temporal magnified electron signal is sampled by a time-resolved MCP imager to achieve a high time resolution.The electron signal time-dilation unit contains a transmission PC,a grounded anode mesh,and an electron drift tube.A negative high DC voltage plus a dilating pulse are applied on the PC to achieve a time-dependent electric field between the PC and the mesh,which results in electron energy dispersion.The photoelectrons bom earlier can acquire larger energy than those later,and they drift faster in the region from the mesh to the MCP.Therefore,the time duration of the electron signal is magnified.Subsequently,the temporal magnified electron signal is sampled by a time-resolved MCP imager.Because of the temporal magnified electron signal,the temporal resolution of the dilation X-ray framing camera is greatly improved.Recently,the progress of microelectronics technology further promotes the development of framing cameras.The single line-of-sight(SLOS)framing imaging system based on CMOS chips achieves a temporal resolution of 30 ps and a spatial resolution of 35 μm.Furthermore,in order to improve the ability to resist electromagnetic interference,an all optical solid-state framing camera has been developed.In this paper,the traditional useful MCP gated X-ray framing technique and the recent dilation X-ray framing technology are both described.Furthermore,the all-solid framing technology and all-optical solid-state framing technology are prospected.
NETL
NSTL
万方数据
维普
