Conceptual design and theoretical analysis of a system: The reference network of alignment

As a fourth-generation light source based on a diffraction-limited storage ring, Hefei Advanced Light Facility (HALF) has higher requirements for the alignment of magnets in terms of accuracy, efficiency and reliability. In this paper, we propose a system called the Reference Network of Alignment (RNA) that can achieve a transverse alignment accuracy of the magnets of ±20μm along a 100 m straight section of the accelerator. We first present the concept underlying the design of the RNA system. The girder assembly on which several common axis magnets are fixed forms the independent unit, and a long stretched wire is used as a straightness reference. A theoretical analysis of our system is then presented based on strict mathematical models that center on the combining method of the wire position sensors, the hydrostatic leveling sensors, and two-axis inclination sensors, for which the positions and orientations are known relative to each other. Finally, we perform a simulation of the RNA system using the Monte Carlo method. The results show that it is credible to assume that the RNA system can achieve an alignment installation accuracy of 20 μm and a displacement monitoring accuracy of 15 μm.