The Optical Constants window is used to set the source position and optical parameters for the detector. This window is only available in the OPTICAL_CAL version of XSNOED.
To perform an interactive optical calibration, first change the display to calibrated hits in the Data menu, then sum an entire run of events for a specific source location. (Note: The summed events are windowed and only prompt hits are summed if you perform the sum in calibrated hits mode. In this mode, hits differing from prompt light by more than 3.5 nanoseconds are not summed.)
The next step is to enter the x,y,z source position (in centimeters) into the Optical Constants window. Then (if a corresponding source position is found in the OCA database file) adjust the acrylic, H2O and D2O attenuation parameters to give a uniform hit distribution. If multiple copies of XSNOED are running, the attenuation parameters are automatically updated in each version. This allows you to determine a set of constants that yield reasonable results for a number of source positions.
The calibrated hit values displayed are the expected/calculated occupancies
for each PMT, normalized to an average of unity. The normalization
constant is given as the Source Intensity at the bottom of this window.
Also displayed is the percentage of hits in the prompt window.