First Steps Toward the Development of a Straight-Line Reference Alignment System for Future Accelerators at CERN Using Pseudo-Nondiffracting Layer Beams

This paper presents experimental results that allow for the performance evaluation of a straight-line reference alignment system based on pseudo-nondiffracting Layer beams (LBs). Sensors, developed specifically for this system, feature four linear CMOS chips and a square aperture. This allows for simultaneous measurements along the beam path without disrupting the laser reference. Measurements, conducted over a distance of 2 m from the first to the last sensor, were compared with state-of-the-art alignment techniques to assess the system performance. The alignment reference generated by the LBs exhibited a repeatability and reproducibility root-mean-square error (RMSE) of less than 30 μm. The relative alignment precision for a known displacement was validated with a standard deviation of 4.3 μm. The results demonstrate the potential for scaling the system to longer distances. The key sources of noise that must be addressed before such scaling can be realized are identified. Additionally, a proof-of-concept for future development of a radiation-hard sensor utilizing optical fiber matrices is demonstrated. The RMSE of the reference position detection introduced by the fiber matrix remained below 1.3 μm. This would allow the sensor to be used reliably in high-radiation environments typical for accelerator facilities. This study serves as a foundational step toward developing a straight line reference alignment system based on pseudo-nondiffracting LBs intended for deployment in the accelerator facilities.