Method and system for tomographic projection correction

A tomography system comprising:

• a rotation stage for rotating a sample and a metrology reference;
• a transmission microscope for capturing a series of projections at different rotation angles of the sample;
• position sensors for measuring mechanical displacements of the sample at the different rotation angles by measuring displacements of the metrology reference with respect to a fixed mechanical reference for each of the projections;
• and
• a controller for shifting the projections by reference to the measured mechanical displacements of the metrology reference with respect to the fixed mechanical reference and then performing tomographic reconstruction using the shifted projections.

A tomography method comprising:

• performing a calibration by measuring displacements of a sample holder with x-ray or transmission electron microscope having a rotation stage for the sample holder at different rotation angles and determining offset and sensitivity information for position sensors that measure mechanical displacement between a metrology reference of the rotation stage and a fixed mechanical reference at each of the different rotation angles;
• capturing a series of projections at different rotation angles of a sample held on the sample holder with the x-ray or transmission electron microscope;
• measuring displacements of the sample at the different rotation angles for each of the projections using the position sensors that measure mechanical position changes between the metrology reference and the fixed mechanical reference;
• storing projection image data with sensor data generated from the position sensors for the angle corresponding to the angle at which the associated projection image data were generated;
• and
• shifting the projections by reference to the measured mechanical position changes of the rotation stage with respect to the fixed mechanical reference and the offset and sensitivity information generated from the calibration;
• performing tomographic reconstruction using the shifted projections.