A Scanning Multi-Probe Straightness Measurement System for Alignment of Linear Collider Accelerator
This paper describes a scanning multi-probe measurement system for local alignment of linac components. The system consists of two probe-units, each having three displacement probes. The two probe-units, which are placed on the two sides of the cylindrical linac components, are moved by a scanning stage with a scanning range of 5 m to simultaneously scan the two opposed straightness profiles of the linac cylinders. A differential output calculated from the probe outputs in each probe-unit cancels the influence of error motions of the scanning stage, and a double ntegration of the differential output gives the straightness profile. The difference between the unknown zero-values of the probes in each probe-unit of zero-difference, which introduces a parabolic error term in the profile evaluation result, is calculated and compensated for by a zero-adjustment method so that accurate straightness profiles of the linac cylinders can be obtained. The effectiveness of the measuring system is confirmed by experimental results.
Yongsheng Gao, Shuetfung Tse and Wei Gao
W. Gao et al., "A Scanning Multi-Probe Straightness Measurement System for Alignment of Linear Collider Accelerator", Key Engineering Materials, Vols. 295-296, pp. 253-258, 2005