To: ACIS Team
From: Beverly LaMarr (fergason@space.mit.edu)
Subject: ACIS Flight Energy Scale and Resolution as a Function of Row
Date: 05 November 1999

This memo presents the energy scale and resolution of the ACIS devices as a function of row position for days 262 through 286 of 1999 where the CTI was stable. Figure 1 is a plot of the average CTI of s2 at -110C.

The data from all 110C external calibration source measurements from days 262 through 286 of 1999 have been summed. For i0, i1, i2 and i3 this includes OBSIDs 1310 1313 1315 1316 62373 62380 62377 62508 62371 62367 62366 62362 62361 62357 62353 and 62350. For s0, s1, s4 and s5 this includes OBSIDs 1311 1312 1314 1317 62375 62509 62379 62378 62370 62368 62365 62363 62360 62358 62354 and 62351. For s2 this includes OBSIDs 1304 1306 1310 1311 1312 1313 1314 1315 1316 1317 62375 62373 62509 62380 62379 62378 62377 62508 62371 62370 62368 62367 62366 62365 62363 62362 62361 62360 62358 62357 62354 62353 62351 and 62350. For s3 this includes OBSIDs 1304 1306 1310 1311 1312 1313 1314 1315 1316 1317 62375 62373 62509 62380 62379 62378 62377 62508 62371 62370 62368 62367 62366 62365 62362 62361 62360 62358 62357 62354 62351 and 62350.

After the data for each chip was summed, the data from each output node has been broken into thirty two thirty two row bins and only the summed pulse heights of ASCA grade 02346 events were considered. For each of the 256x32 pixel bins, a gaussian was fit to each of the three main peaks (Mn Kalpha at 5894 keV, Ti Kalpha at 4510 keV, and Al K at 1487 keV).

Table 1 summarizes the total number of ASCA g02346 events from 0 to 2000 ADU, as well as the average number of counts in each of the gaussian fits for each CCD.

Figures 2 through 31 are plots of the peak location of the gaussian fit to the ASCA g02346 events for each of the thirty two row bins.

Figures 32 through 61 are plots of the full width half max in eV of the gaussian fit to the ASCA g02346 events for each of the thirty two row bins.

Figures 62 through 81 are plots of slope and intercept of the energy scale for each of the thirty two row bins.

Also plotted here, as Figures 82 through 91, are the total number of ASCA g02346 events from 0 to 2000 ADU in each of the thirty two row bins. The first of the bins is low due to shadowing of the framestore cover over the first several rows. These plots are included to give an indication of the number of ''good'' events that are lost into ''bad'' grades due to the CTI.

Similar plots for ground data taken of the external calibration source at -110C can be found following the plots of flight data.

Table 1. Number of Counts

External calbration source data was taken with the focal plane at -110C while the ISIM was in thermal vac testing at Ball in October of 1997. Table 2 summarizes the total number of ASCA g02346 events from 0 to 2000ADU, as well as the average number of counts in each of the gaussian fits for each CCD.

Table 2. Number of Counts

The data from each output node has been broken into thirty two thirty two row bins and only the ASCA grade 02346 events were considered.

Figures 92 through 121 are plots of the peak location of the gaussian fit to the ASCA g02346 events for each of the thirty two row bins.

Figures 122 through 151 are plots of the full width half max in eV of the gaussian fit to the ASCA g02346 events for each of the thirty two row bins.

Figures 152 through 171 are plots of slope and intercept of the energy scale for each of the thirty two row bins.

Also plotted here, as Figures 172 through 181, are the total number of ASCA g02346 events from 0 to 2000 ADU in each of the thirty two row bins. The first of the bins is low due to shadowing of the framestore cover over the first several rows. These plots are included to give an indication of the illumination pattern of the external calibration source.