  We give the results of an analysis of some 18 rise-time calibrations which
are based on data collected in 1996/97. Such measurements are used to determine
the absolute polarization scale of the transverse electron beam polarimeter
(TPOL) at HERA. The results of the 1996/97 calibrations are found to be in good
agreement with earlier calibrations of the TPOL performed in 1994 with errors
of 1.2% and 1.1%. Based on these calibrations and a comparison with
measurements from the longitudinal polarimeter (LPOL) at HERA carried out over
a two-months period in 2000, we obtain a mean LPOL/TPOL ratio of 1.018. Both
polarimeters are found to agree with each other within their overall errors of
about 2% each.

High Energy Physics - Experiment