First steps toward the development of a straight-line reference alignment system for future accelerators at CERN using pseudo-nondiffracting Layer beams

Abstract 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>30</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mtext>μ</mml:mtext> <mml:mrow> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:mrow> </mml:math> . The relative alignment precision for a known displacement was validated with a standard deviation of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>4.3</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mtext>μ</mml:mtext> <mml:mrow> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:mrow> </mml:math> . 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 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mn>1.3</mml:mn> <mml:mstyle scriptlevel="0"/> <mml:mtext>μ</mml:mtext> <mml:mrow> <mml:mi mathvariant="normal">m</mml:mi> </mml:mrow> </mml:mrow> </mml:math> . 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.