Introduction

The Hall C analysis engine uses corrections for pulse height walk and channel-to-channel timing differences to get good timing resolution from the HMS and SOS hodoscopes. Whenever there are changes to the timing dependence on the pulse height from the scintillator PMTs¹ or changes to any electronics upon which timing depends,² you need to refit the pulse-height corrections and/or time offsets in order to get optimum time-of-flight (TOF) resolution. If only timing has changed then only time offsets need to be recalculated. On the other hand, if timing dependence on the pulse heights has changed, then you must first calculate new pulse-height coefficients and then find new time offsets. Corrections to account for light velocity in the scintillators are also made, but these are very stable; most people will never need to change them.