F.9 Quantitative Illustration

quantity min max mean st.dev. relevant corrections

-1.0156 +0.0312 -0.4942 0.2890 NLC

0.0000 +39.594 +0.3654 1.3463 GSC

-1.0156 +39.000 -0.1289 1.3768 NLC + GSC

+2.4844 +113.57 +17.250 13.409 TGC

+1.4844 +152.57 +17.121 14.364 NLC + GSC + TGC

-17.070 +18.945 -0.4353 1.1322 SGC

+1.3359 +162.56 +16.686 14.032 NLC + GSC + TGC + SGC

-9.0000 +20.750 +0.1771 2.6969 EPC

-21.875 +24.125 +3.3085 6.7258 WC

-22.750 +30.500 +3.4856 7.5448 EPC + WC

-2.0000 +1.7500 -0.2686 0.6963 FC

-21.500 +29.250 +3.2170 6.9006 EPC + WC + FC

-18.500 +19.625 +2.0454 8.7856 EPC

-21.625 +16.750 -4.5542 5.1255 WC

-36.625 +32.625 -2.5088 10.726 EPC + WC

-1.8750 +1.8750 +0.0447 0.7187 FC

-34.750 +30.750 -2.4640 10.296 EPC + WC + FC

Table F.3: PSPC observation WG700513P (Mkn 421): all events within a circle with (XPIX, YPIX are sky coordinates relative to the nominal position, all values in units of 0.5 arcsec) have been selected and the statistical effects of individual corrections have been investigated. The table contains the minimum and maximum value, the mean and the standard deviation of each correction as well as of the cumulative correction. Since the selected photons originate only from a small portion of the detector not the full effects are visible but the effects on near-on-axis photons.

Here we want to summarize the previously introduced corrections in a quantitative manner. Table F.3 shows the effect of each correction step for Mkn 421, observed in May 1992. The large effect of the gain corrections in low-gain mode (maximum

) is shown up as well as the large spread in the electronic position correction along the y-axis. The mean shift

is -0.49 channels.