Research On The Key Technologies Of Space X-ray Communication

X-ray communication?XCOM?is a novel space communication method that transmits information by using X-ray carriers.Compared with microwave and laser,XCOM has the merits of high frequency,large photon energy and strong penetrating ability.Therefore,XCOM could realize high-speed and long-distance transmission in spatial environment,especially on condition of electromagnetic shielding.This paper mainly focus on key devices and core theories of XCOM,such as X-ray emit source,transmission model in free space,plasma sheath and spatial charged particle environment,which laid the foundation of further research on space XCOM.In this paper,the feasibility of XCOM transmission in space were analysized firstly.Then the power transmission model,noise model and bit-error-ratio model were established and verified by using a 10m vacuum XCOM demonstration system.Experiment results accord well with theoretical analysis,which also indicate that MCP?Micro Channel Plate?and SDD?Silicon Draft Detector?detector can get40kbps and 100kbps transmitting speed respectively.These theoretical and experiment results provide some guidances for the optimal design of space XCOM system.Considering the strong particle property of X-ray photons,by introducing the collision model,the transmission model of X-ray photon in plasma sheath were re-explained and optimized.Then a XCOM demonstration system based on the glow discharge plasma source was used to verify theoretical results.The transmission efficiency of X-ray signal in plasma sheath were firstly analysised.Experiment results pointed out that X-ray signal could get more attenuation with the increase of plasma electron density.When the plasma electron density ranges from 6×10¹⁶/m³to1.2×10¹⁷/m³ with 18cm thickness,1.34Mcps signal X-ray photons flow with 20kV anode voltage would achieve more than 95%transmission efficiency.In addition,considering the re-enter plasma sheath has the characteristics of dynamic,non-uniform and dusty,an alkali metal plasma source was used to simulate these features for simplification.Then,transmission efficiency under different X-ray flow were tested,which pointed out that X-ray signal would achieve more than 80.3%transmission efficiency on condition of the dynamic dusty plasma.In order to achieve a X-ray source suitable for spatial XCOM,a MCNP?Monte Carlo N Particle?transport code and three-dimensional electromagnetic fieldsimulation were applied to optimize the grid-control X-ray source.By simulating the quantum efficiency of X-ray photons under different structure and anode material,the slot structure,sink depth,anode thickness and grid structure of X-ray source wasoptimized and a new X-ray source was manufactured.Experiment results confirmed that more that 16%X-ray photons were produced after optimize the grid control X-ray source.Finally,considering the influence of spatial charged particles on XCOM system,an experimental platform for electron gun interact with the coating material of nested X-ray focusing optical was build.Experimental results show that nested X-rayfocusing optics can filter the interference of space charged particles,and the SNR?Signal to Noise Ratio?of the experimental system is better than 15.1dB.