As was mentioned above, the cosmic rays are used to calibrate the detector
on a continual basis. This means that while the detector is gathering data
on neutron polarization it is also gathering calibration data. Offline the
calibration data are used to recalibrate the software offsets for each
individual run (one run = 
hours of data-taking) before other
quantities are extracted to insure that the data remain accurate. There
are five different calibrations performed on the data for each run: pulse
height gains, position time offsets in each cell, relative time offsets
between cells in a plane, relative timing offsets between the planes, and
overall timing offset for the detector. Each of these will be described
below.