Research On The Technology Of The Ultrahigh Vacuum Medium Energy Crystal Monochromator

With the development of synchrotron radiation technology,synchrotron radiation light with excellent performance makes it play an irreplaceable role in many fields, but in most applications, monochromatic synchrotron radiation is often required, the monochromator can achieve the monochromatic beam. In order to study the mechanism of biological cells, viruses and other biological cells by synchrotron radiation monochromatic light, the related technology research of double crystal monochromator was carried out in this paper. And the research also will promote the development of biology and medicine. According to the application requirements of the actual research, the monochromator only require to output three energy points beam line, these energy points are 2.1 keV,2.3 keV and 2.5 keV respectively, the energy resolution △≤5×10-4, the repeated precision of angle less than 3 ".Based on the application requirements and the research of traditional crystal monochromator, an innovative double crystal monochromator structure was proposed in this paper. The structure is mainly based on the crystal moving system, crystal fine adjustment system and the flexible hinge. The double crystal monochromator achieve the monochromatic beam based on Bragg diffraction condition, different energy points of light is corresponding to different Bragg angle. The monochromator applys three separate cutting groove crystals and can output beam line which energy point is 2.1 keV,2.3 keV,2.5 keV respectively. Firstly, the mobile system which can accurately switch the three pieces of crystal consists of crystal fixing structure and crystal moving device. Crystal fixing structure consists of crystal mounting base, crystal support, crystal connecting plate and so on. Crystal moving device consists of main shaft device, linear guide rail lead screw and so on. Secondly, to meet the requirements of crystal diffraction angle, the crystal fine adjustment system was designed, which based on the flexible hinge, the push rod and the stepper motor. Crystal moving system and crystal fine adjustment system are closely linked together through the angle adjusting upper and lower plates. In addition, a new technique for thermal release of crystal is proposed by research on the cooling technology of the crystal. The new technique based on copper braid and indirect water cooling, it can meet the practical application requirements. Finally, the main performance parameters of double crystal monochromator device was measured, including the crystal angle repeated precision and crystal repeated positioning precision. According to the actual measurement data analysis, the crystal angle repeated precision is less than 3", crystal repeated positioning accuracy is less than 30", so it meets the research objectives. The study of double crystal monochromator has the advantages of simple structure, convenient operation, outstanding performance. This research has laid a good foundation for the follow-up study of the monochromator.