Distortion reduction in a multi-beam imaging system

A system comprising:

• an imaging sub-system utilizing multiple particle beams, wherein the imaging sub-system includes one or more detectors and one or more control elements to manipulate two or more particle beams, wherein the one or more control elements comprise at least one of lenses, rotators, magnifiers, or stigmators, wherein the one or more control elements are adjustable with two or more control parameters;
• and
• a controller configured to be coupled to the imaging sub-system, wherein the controller includes one or more processors configured to execute program instructions causing the one or more processors to:
• iteratively performing one or more steps until one or more termination conditions are met, wherein the one or more termination conditions include at least one of a distortion threshold, reaching a minimum difference between calculated values from two sequential iterations, or reaching a maximum number of iterations, wherein the one or more steps include:
• direct the imaging sub-system to individually adjust the two or more control parameters and receiving measurements of changes of distortions of the two or more particle beams resulting from the individual adjustments, wherein the distortions are associated with at least one of positions or aberrations of the two or more particle beams;
• associate the measurements with proportionality constants of a linear predictive model to relate the changes of distortions of the two or more particle beams to the individual adjustments of the two or more control parameters;
• and
• calculate values of the two or more control parameters that correspond to at least one of a local minimum or an absolute minimum of the linear predictive model;
• and
• adjust settings of the two or more control parameters of the imaging sub-system to the calculated values.

A method comprising:

• directing two or more particle beams to a sample plane with an imaging system including one or more detectors and one or more control elements for manipulating the two or more particle beams, wherein the one or more control elements comprise at least one of lenses, rotators, magnifiers, or stigmators, wherein the one or more control elements are configurable with two or more control parameters;
• iteratively performing one or more steps until one or more termination conditions are met, wherein the one or more termination conditions include at least one of a distortion threshold, reaching a minimum difference between calculated values from two sequential iterations, or reaching a maximum number of iterations, wherein the one or more steps include:
• individually adjusting the two or more control parameters and generating measurements of changes of distortions of the two or more particle beams resulting from the individual adjustments, wherein the distortions are associated with at least one of positions or aberrations of the two or more particle beams;
• associating the measurements with proportionality constants of a linear predictive model to relate the changes of distortions of the two or more particle beams to the individual adjustments of the two or more control parameters;
• and
• calculating values of the two or more control parameters correspond to at least one of a local minimum or an absolute minimum of the linear predictive model;
• and
• adjusting settings of the two or more control elements to the calculated values.