ULYSSES

Ulysses HISCALE Data Analysis Handbook

5,2.3 PHA Analysis

This section describes an analysis that was undertaken in IDL to better understand the SEEPHA matrix. Figure 5.18 shows a 3D plot of the matrix shown in Figure 5.9 made with the IDL routine shade_surf. The tallest peak corresponds to the Cm source. The peak corresponding to the Gd source is to the left of the Cm peak and towards the top of the figure. The large number of scattered He which are counted as H because of the priority scheme can be seen in the elongated peak in front of the Gd peak and in the peak to the right of the Cm peak.

Figure 5.18 PHA matrix for 92049 calibration

Figure 5.19 PHA matrix for 92049 calibration

The matrix was divided into five areas as shown in Figure 5.19, and PHA matrix for 92049 calibration. Summations were made over each section to determine the number of counts in each region. It is difficult to draw many conclusions because of the distortions created by the priority scheme. However, one can compare the percentages in each area from one calibration to the next to verify that they don't change very much. This is done in Table 5.14.

Table 5.14 PHA counts/percentages

 Date/Time CM peak Gd Peak Area A Area B Area C 93019.20-22 3193/36.1 1375/15.6 3488/39.4 597/6.8 172/1.9 92009.22-24 2079/39.2 917/17.3 1875/35.3 386/7.3 42/0.8 92049.20-22 3705/42.1 1613/17.9 3034/33.7 578/6.4 65/0.7 93008.14-16 3652/41.5 1560/17.7 2979/33.8 538/6.1 50/0.6 94091.10-12 3540/39.2 1782/19.9 2997/33.4 575/6.4 46/0.5

Here the left column gives the time of the 2-h period during which the data in the table were accumulated. The table entries give the total number of counts in each of the areas delineated in Figure 5.19, followed by the percentage of the total counts that this represents. The number of counts during the 2h period of the 92009 calibration are about half those during the same length intervals during the other calibrations. This is because the spacecraft telemetry rate was a factor of 2 lower at this time. Another look at the same data can be had from the trackrate files with the program TRACKDUMP. Such a printout for 92049.20-22 is included as Table 5.15 (below). The PHA event counts in W4 (the high energy He channel) are slightly less than the counts found above in the Cm peak for this time. There are several hundred more counts in W3 than were found in the Gd peak. These were probably in the area of W3 that was included in Area A. There are more total PHA counts in W3 and W4 than in W1 and W2, but only 60% more, whereas the rate channels give a He/H ratio of 48:1; this is due to the PHA priority scheme described above. W4 (Cm peak) contains 64.1% of the total counts, W3 (Gd peak) contains 33.8%. The H channels (W1 and W2) each contain only about 1% of the rate counts. One can also check the distribution vs sector from this table: the minimum W4 rate channel counts in sector 8 are 12.4% of the total, the maximum in sector 4 is 12.6%. It is reassuring to look at the Undefined Event Counts and to see that practically all of the PHA event counts in channels W1 and W2 fall outside of the defined track bins. About 15% of the W3 counts are undefined; less than 6% of the W4 counts are.

Table 5.15 Track dump output 92049

 LAN PHA Track Rate Record Begin time: 92 49 20 0 0 End time: 92 49 22 0 0

PHA event counts

 Channel Sector 0 1 2 3 4 5 6 7 8 W0 9026 1128 1128 1128 1128 1128 1128 1128 1130 W1 1383 165 160 170 165 181 171 196 175 W2 2079 275 268 248 252 244 262 261 269 W3 1890 245 242 248 214 232 239 232 238 W4 3673 443 458 462 496 471 456 439 448 W5 0 0 0 0 0 0 0 0 0 W6 1 0 0 0 1 0 0 0 0 W7 0 0 0 0 0 0 0 0 0 W8 0 0 0 0 0 0 0 0 0

Rate channel counts

 Channel Sector 0 1 2 3 4 5 6 7 8 W0 256106 32300 31955 31884 32009 32168 31959 31966 31863 W1 2099 260 250 247 248 277 254 292 267 W2 3129 382 400 375 382 372 390 409 416 W3 86568 11011 10878 10706 10721 10964 10665 10844 10776 W4 164291 20645 20409 20555 20656 20544 20647 20419 20403 W5 0 0 0 0 0 0 0 0 0 W6 17 0 16 0 1 0 0 0 0 W7 0 0 0 0 0 0 0 0 0 W8 0 0 0 0 0 0 0 0 0

Undefined event counts

 Channel Sector 0 1 2 3 4 5 6 7 8 W0 0 0 0 0 0 0 0 0 0 W1 0 165 159 169 165 181 169 195 173 W2 0 275 268 247 252 244 262 261 269 W3 0 45 22 26 25 36 34 29 30 W4 0 38 16 21 22 18 22 16 15 W5 0 0 0 0 0 0 0 0 0 W6 0 0 0 0 1 0 0 0 0 W7 0 0 0 0 0 0 0 0 0 W8 0 0 0 0 0 0 0 0 0

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