ABSTRACT
X-ray communication is a kind of space communication technology which uses X-ray as information carrier. In order to improve the information transmission capacity, communication rate and anti-interference ability of X-ray communication, we proposes to design a novel multi-target X-ray source. The source is composed of a fast switching module of light channels based on FPGA technology and four photoelectric X-ray tubes with different target materials: Cr, Fe, Ni, and Cu. Using Geant4 software, we determined the optimal target thickness for each material, which enabled us to fully leverage the characteristic X-rays for multi-channel signal modulation transmission. Moreover, using CST software for particle trajectory simulation and optimization of the electron beam revealed that at a tube voltage of 20 kV, the focus area measures approximately 1.2 mm×1.2 mm. The simulations show that four kinds of spectra with high distinctiveness can be generated from the Cr, Fe, Ni, and Cu targets. Within a single modulation period, these spectra can be combined in various ways to create 16 different X-ray spectra signals, thereby increasing the number of communication elements and enhancing the information transmission rate.
ABSTRACT
A MCNP model of a252Cf source-based prompt gamma-ray neutron activation analysis (PGNAA) system for bulk sample analysis was benchmarked. The indium foils activation and aqueous samples containing chlorine were measured using the PGNAA system, and the experimental data compared to the simulations. The discrepancies between the measurements and simulations are within 6% and 20% for thermal neutron flux and prompt gamma-ray response, respectively. The results show that the simulations agree well with the measurements, and demonstrate the proposed MCNP model can represent the system.
