Survey And Alignment Of The HLS Ⅱ Upgrade Project And Study Of The Measurement Precision

With the support of Chinese Academy of Sciences (CAS) and University of Science and Technology of China (USTC), National Synchrotron Radiation Lab (NSRL) has upgraded Hefei Light Source (HLS) on the existing structure since 2010. The new light source, HLS II, equips experiments with brighter and more stable synchrotron light. The alignment is in progress along with the whole upgrade project, and the precise installment of key elements is the foundation of accomplishing the upgrade project smoothly.The thesis studies the alignment processing in the upgrade project completely, including the design of engineering control network, measurement and installation of all elements. We conducted research in the smoothing methods of the beam orbit in the HLS II storage ring to improve the work efficiency after completely adjusting all core elements. On the other hand, we established a test platform and performed expansive study on the laser tracker to improve the precision of measurement. The study and production of the thesis mainly include the following several aspects:Combining the construction features of HLS with the original engineering control network targets, we redesigned the engineering control network and optimized the first plane control network. After actual measurement, the first plane control network, the elevation control network and the three-dimensional control network were adjusted and their precision were evaluated.The three-dimensional adjustment methods were thoroughly studied combined with the engineering control network of HLSII. In the thesis, the principles of three-dimensional adjustment, three-dimensional adjustment based on the Helmert variance component estimation and United Space Metrology Network (USMN) were introduced in detail. The three different adjustment methods were adopted to process the control network measurement data, and the adjustment results were compared to deeply expound the difference of these adjustment methods.The key elements such as magnets, accelerator cubes and undulators were pre-aligned, and the pre-alignment errors were analyzed. The installation methods which based on global coordinate system and element coordinate system were analyzed and compared. We reasonably adopted these two different installment methods practically considering the structure features of HLSII, which guarantee the installment precision and work efficiency.During the storage ring installation process, these magnets should be finally accurately aligned to determine the smoothing of beam orbit after all magnets were installed and aligned. It asks that all the storage ring magnets to be placed with a relative higher accuracy under the stringent demand of accelerator physics. A reliable and simple smoothing method was developed by studying and analyzing the experience and merit of other smoothing methods. The method has simple implementation and similar work efficiency to the low-pass filtering and spline function smoothing method. The whole smoothing process can be coded based on MATLAB programing.The engineering control network and every elements in HLSⅡ were re-surveyed after one year’s test and half year’s formal running. We analyzed the transformation with the final alignment results.It is necessary to calibrate and check these measurement devices before the program, in the program and in the field work. Based on the hardware and software of NSRL, we had established a test platform to calibrate the laser tracker performance which includes distance accuracy and angle accuracy. Meanwhile, in-site calibration of laser tracker was studied to check the measurement accuracy in the field work. Finally, the influence of environmental factors on laser tracker measurement was also studied by using the temperature and humidity sensor.In summary, the main contribution and innovation of the thesis mainly include the following aspects:USMN processes including the point computation optimization, instrument transform optimization and uncertainty extraction from optimization results are introduced in detail. A reliable and simple smoothing method is developed according to the construction features of HLSII, and the smoothing method is suitable for other accelerators. A test platform is established to calibrate the laser tracker, field check method is developed and the influence of environmental factors on laser tracker measurement is also studied. The measurement accuracy of laser tracker can be completely calibrated and checked at NSRL.