From Bill, explanation of the screenshot and suggestions for how to setup run number ranges: On the left the files shown are from my a1nd2n replay /group/c-polhe3/Users/wmhenry/hallc_replay/DBASE/SHMS/standard.database /group/c-polhe3/Users/wmhenry/hallc_replay/DBASE/SHMS/general.param On the right the file is from my F2 replay /group/shms/wmhenry/f2-xem/DBASE/SHMS/STD/standard.database To assign specific calibration files for specific runs I think this is what needs to be done. 1) copy the general.param file and give it a unique name like a1n.param or d2n.param. That file should have the same structure as general.param and is a list of all the calibration files needed. You will have a param file for each group of runs that have different calibration files. 2) Modify the standard.database file which will assign the correct param file for a given run. This file sets the variables g_ctp_param_filename and g_ctp_kinematics_filename for a given run number. It gets used in the main replay script. For your replay that is /group/c-polhe3/Users/wmhenry/hallc_replay/SCRIPTS/src/replay_shms.cxx. I have attached a screen shot of the relevant lines in the replay script.