The Study On Micro X-ray Tube Power Supply System

The portable X-ray elemental analysis instrument which was developed by using elements characteristic X-rays has been widely applied in ocean exploration, geological surveys, environmental monitoring, mining and other elements for rapid analysis. As the key component of a portable X-ray elemental analyzer, miniature X-ray tube has a very important practical uses and market prospects. However, the core technology of micro-X-ray tube has not mastered in our country at present, and the vast majority of commercially available miniature X-ray tubes are imported from abroad.As the core part of the miniature X-ray tube, the power supply system is developed by Roentgen team at the next year of X-ray was found. Initially, X-ray power system used a frequency inverter. With the advances in electronic technology, there is IF inverter circuit. With the further development of technology, after the 1990 s, X-ray power system frequency and from IF to upgrade to a high-frequency, and the appearance high frequency power supply system has great significance for the development of X-ray equipment, which reduces the output filter circuit capacitance requirements and the output ripple voltage, not only improves the efficiency of the power system, but also reduces the volume and reduce the weight. Therefore, since the high-frequency inverter begins to be applied to the X-ray tube power supply system, and it has been a high-voltage X-ray generating device mainstream DC power inverter technology.At present, the domestic X-ray tube power systems is mainly for medical and industrial fields. That kind of X-ray tube power is generally large, less efficient and large power, and it is not suitable to portable fluorescence analysis. Used in portable fluorescence analyzer miniature, X-ray tube has more stringent requirements in power, volume and efficiency.This article describes a power supply system that is developed for special power supply system which is used in miniature X-ray tube. First, by comparing the advantages and disadvantages of different circuit configuration, we chose the appropriate circuit structure to accommodate the technical requirements of miniature X-ray tube power system. Then, the electromagnetic interference method and packaging processes were studied, and made a test about the performance indicators of the power system.This paper studies comes from a 863 plan resources in the field of environmental technology topics “high-precision ray detection equipment R & D "(Project No.:2012AA061803). Fluorescence analysis needed for portable micro X-ray tube power system circuit design and test, the main work and achievements of the paper are as follows:1. In accordance with the miniature requirement of X-ray tube, we designed and developed a new high-voltage DC power supply. We selected Royer resonant circuit as a high voltage DC power inverter circuit which is a self-excited oscillation, small volume and no switching noise circuit and design the parameters. Meanwhile, in order to improve the efficiency of the circuit, we used a chip UCC2973 as resonant current modulation. The step-up part of the circuit design was the high-frequency transformer and voltage doubling rectifying circuit. Regulators way was the sample feedback loop control. After the actual circuit high voltage DC power supply was made, we used electrical equipment potting material to make it cut off the air in a vacuum chamber, then there was a performance testing for it. We measured the output ripple coefficient of the high voltage DC power supply is lower than 0.3%, and the stability of the power supply voltage is better than 0.10%/10 h, which met the requirement of micro X-ray tube.2. According to the requirement specification of miniature X-ray tube filament power supply, we designed the filament power supply that was based on high-frequency electromagnetic coupling method. It was low voltage DC power supply and suitable for field application. Thus, it was easier to achieve precise control of filament current. We adopt the high frequency push-pull mode,and electromagnetic field coupled energy. Not only improving the efficiency of energy transfer, but also reducing the size and weight of the overall system in order to facilitate a portable work. The filament power supply’s consumption test was connected to a 1.5? power resistor power. The input power of 11 W, and its efficiency was over 80%, and it met the requirements of the filament power consumption indicators.3. Elaborate the problems about the process and reliability when we develop the practical circuit of the power system. It involves the suppression circuit trace layout, power supply systems, electromagnetic interference, select high-voltage components, various protection circuits and high voltage insulation measures system.4. The high-voltage DC power supply and filament power supply is applied to the micro-X-ray tube, and we used electrical equipment potting material to make it cut off the air in a vacuum chamber, then there was a performance testing. The experiment results show that the design of miniature X-ray tube X-ray power supply system can stimulate the X-ray source give off stable X-rays, and it achieves the desired effect. Therefore, this micro X-ray tube power supply system could meet the needs of portable fluorescence analysis.