OnDA Solution Scattering enables real-time analysis of solution scattering data at XFELs. 

Originally designed for serial crystallography by Valerio Mariani at CFEL, OnDA enables real-time analysis of experiments before data are even written to disk. This allows for feedback within seconds of data collection, as opposed to several hours without OnDA. BioXFEL researcher Tom Grant and summer student Sarah Chamberlain have developed a solution scattering module of OnDA that performs radial integration, normalization, cumulative averaging, and “hit finding”. This feedback is crucial for the efficient use of beamtime as it provides information about whether or not the data being collected are useful and can immediately alert researchers to data collection problems. For example, the hit finder feature is useful for ensuring that the sample delivery jet is properly aligned with the X-ray beam. If misalignment occurs (common during shifts), the hit rate immediately drops within seconds and the injection team can be notified to make quick adjustments, limiting significant loss of beamtime. The module has been designed with time-resolved experiments in mind and can accommodate pump-probe and mix-and-inject set ups. The module has been installed centrally at LCLS and is available for all users, as well as being incorporated into the main OnDA package.