Speaker
Description
The "Millepede" algorithm, for refining the geometry of complex multi-component particle physics detectors, was introduced in the late 1990s. The same approach, and in fact the same software, can be applied to serial crystallography for refining the positions and orientations of segmented X-ray detectors. The Millepede approach allows simultaneous joint refinement of the detector geometry parameters alongside the crystal parameters (orientation, lattice parameters etc) for each individual frame in the dataset. A joint refinement is required, otherwise the refinement will be biased and not convergent. Since serial crystallography datasets consist of very large numbers of diffraction patterns, this joint refinement would usually involve solving a very large matrix equation, quickly becoming too time-consuming to form part of a routine analysis pipeline. With Millepede, the matrix size can be reduced to the number of detector geometry parameters, which is much smaller. This leads to a speedup of several orders of magnitude.