Recently, Group led by Zhao Baosheng developed a new type of X-ray modulator and an X-ray detector based on MCP which are respectively the launcher and receiving systems. It realized the experiment of new space X-ray communication method.
In 1895, the German physicist W.K. Roentgen discovered X-ray whose wave is short but has strong penetrability and it could make a lot of invisible solid materials give off visible fluorescence. Therefore, X-ray has been widely used in medical perspective and nondestructive inspection. Actually, as short-wave electromagnetic wave, X-ray could also transmitted in space and successfully realize the function of communication.
At present, the research of space wireless communication has been adopted in many fields, for instance, airwave, microwave, infrared, visible light and ultraviolet, otherwise, the utilization of X-ray communication research is blank. Consequently, it has important scientific meaning and good application prospects to study a new concept space communication method based on X-ray.
With short wave and strong penetrability, the transmittance of X-ray is 100% when its photon energy is greater than 10 kilo electron volt (wavelength short than 0.12nm.) and the atmospheric pressure is below 10-1 Pascal, its transmission has hardly any weakening. It means very low transmitting power could realize distance space communication. So compared with other electromagnetic wave such as microwave and laser, X-ray is equipped with good directivity, low transmitting power, distant transmission range, strong confidentiality, free from EMI of space environment and wide communication band. All these merits may help to realize satellite time communication. In 2007, the astrophysicists of Goddard Space Flight Center of NASA Keith Gendreau proposed to use X-ray to realize point communication among satellite spacecrafts. This concept was considered “the new space communication method of next generation”.
The X-ray modulator developed by Zhao Baosheng Group is a combination of vacuum triode and X-ray tube technologies and it realizes high speed modulation of X-ray energy. In theory, the bandwidth of an emission could reach to 50GHz. Meanwhile, since the X-ray detector based on MCP has advantages such as rapid response, great receiving area and small lowest detectable power, when the divergent angle of X-ray is less than 2 milliradian, its photon energy is more than 20 kilo electron volts and the transmitting power is 100 milliwatt, it could transfer over 6000 km in the space.
For now, XIOPM has established X-ray digital transmission verification system which is based on voice communication, mainly including X-ray launching and receiving devices. It has already realized the voice communication under the OOK and PWM modulation systems and the communication speed could reach to 64 kbps in a 6m vacuum line.