Abstract:
Background With the increasing requirement of beam stability in particle accelerators, the accuracy of engineering control network is required to be higher.
Purpose This study aims to elaborate on the specific observation scheme for large-scale tunnel control network, and introduce the control network layout, measurement mode and data processing procedures.
Methods In this paper, taking the booster of high energy photon source (HEPS) with a circumference of 454 m as an example, aiming at the disadvantages of narrow space in the tunnel, the control network layout scheme and measurement method based on laser tracker precision measurement are proposed. At the same time, in the face of the problem of data validity detection of multiple stations and close points in the measurement process, the quality control method of adjacent single station fitting and multi-station fitting is proposed, and the point fitting error root mean square (RMS) is better than 0.1 mm.
Results Finally, the absolute point error RMS of radial, tangential and elevation coordinate components of the control network reaches 0.2 mm, which meets the installation accuracy requirements of the equipment. At the same time, in order to monitor the stability of the booster after the initial construction, two phases of the booster control network were observed over a one-year period. The measurement results show that the deformation of the booster tunnel is about 10 mm within this period. The specific manifestation is that the tunnel foundation expands outward in the three areas of southeast, northwest and southwest.
Conclusions Overall, the point accuracy of the three directions of the control network is different. The correctness and reliability of the results of the control network can be ensured through multiple control network measurements and data processing and analysis, which provides a reference for other synchrotron radiation light sources.
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