A Stochastic approach in uncertainty budgeting for Accelerator pre-alignment - Study for the CLIC project

A new strategy for uncertainty budgeting estimation following the International Standard (GUM -Supplement 1) is proposed as alternative to current classical methods of error budgeting applied in the domain of accelerator components. This strategy applies stochastic modelling on the uncertainty contributing factors for providing probability density function as quantification of pre-alignment measurements uncertainty. As a case study the methodology is applied to the PACMAN pre-alignment project providing a ‘measurement specific’ uncertainty budget for accelerator pre-alignment of components according to GUM Supplement 1. With this methodology the global uncertainty budget can be determined as function of the exact conditions of each specific contributing factor (temperature and its gradients, measurement strategy, instrumentation, etc.). We believe that this methodology would provide a more accurate approach on the tight uncertainty budgeting allocated for the alignment requirements of the future particle accelerators projects. The method could be easily extrapolated/applied for uncertainty budgeting of different type metrology systems.