Effect of multiple coulomb scattering on the beam tests of silicon pixel detectors

In the research and development of new silicon pixel detectors, a collimated monoenergetic charged-particle test beam equipped with a high-resolution pixel-beam telescope is crucial for prototype verification and performance evaluation. When the beam energy is low, the effect of multiple Coulomb scattering on the measured resolution of the Device Under Test (DUT) must be considered to accurately evaluate the performance of the pixel chips and detectors. This study aimed to investigate the effect of multiple Coulomb scattering on the measured resolution, particularly at low beam energies. Simulations were conducted using Allpix\(^2\) to study the effects of multiple Coulomb scattering under different beam energies, material budgets, and telescope layouts. The simulations also provided the minimum energy at which the effect of multiple Coulomb scattering could be ignored. Compared with the results of a five-layer detector system tested with an electron beam at DESY, the simulation results were consistent with the beam test results, confirming the reliability of the simulations.