Filtering

The Hall B collaboration performs many experiments using CLAS at the same time. Hence, many people's analysis use only certain portions of the data. Resources would be a wasted if many people had to run through the same data file to find their hundred or so events every time they re-examined their data. It would also waste resource time if people needed to retrieve these full data files from the silo. An effort has been made, therefore, to skim through the data files to extract events that appeal to a large audience in the CLAS collaboration.

• e_filter: A large portion of the CLAS experimental program revolves around strangeness electroproduction. e_filter skims through the data file to keep events which pass a W cut and/or a hadron mass cut. It is currently used in the ``cooking'' process to keep only events which contain a kaon.
• g_filter: g_filter performs the same function for photon data as e_filter does for electroproduction.
• physfilter: Attempts to produce a data file with an enhanced number high multiplicity events. The program can be run in several different modes, for electron processing it extracts event with at least two negative and two positive time based tracks, in photon running it selects events with at least one negative and two postitive time based tracks.