SOFTWARE DEVELOPMENTS FOR PROCESSING SOLUTION SCATTERING DATA

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The improved electronic stability made the MarCCD165 detector highly effective in recording solution scattering data last year, in addition to using the gas chamber and image-intensified CCD detector systems. We consequently begun developing MarParse, a new program for converting the 2D raw data into a universal data format expressed in I(Q) vs Q through several steps of numerical data processing and background subtraction. We extended the application range of this program to cover time-resolved data recorded by the intensified CCD detector earlier this year. In addition, we have made a number of important improvements to MarParse:1) alterations in the parameter file format, which now allows users to insert comments on the parameters and process multiple series of data in one parameter file; 2) additional functionalities, such as, evaluating and using different detector offset values in different quadrants, and the use of a mask file for data integration; 3) support for additional data types, such as those from image-intensified CCD and the ASCII format beam intensity files generated by the EMBL gas detector data collection system; 4) faster data processing speed, which cuts the processing time by 10 times. The use of individual detector offset value is particularly significant because even a small offset drift would make background subtraction extremely challenging due to very weak level of scattering signal at intermediary scattering angles where protein solutions scatter only slightly above the matching buffer solution. The rapid data processing capability of MarParse provides highly effective data collection experience, especially in time-resolved studies, by allowing them to select experimental conditions carefully in a much more timely fashion than before. Almost all of the solution scattering experiments at BL4-2 benefit from this development.