The Telemetry Data Processing

The telemetry event list is from Science Run 72, which began on 09 May 1997 at 17:48 GMT as TRW ID I-IAS-SG-2.008. The parameter block used was xfaint_win_s.te. xfaint_win_s.te is full frame, faint telemetry, trickle bias, with a window.

The window block used was xsik56b50.2d. For the s4 chip, this has two windows. The first window begins at row 9 (counting from 0) and is 28 rows high. The second window begins at row 972 and is 28 rows high. All 1024 columns were telemetered.

The first event for the science run was on 09 May 1997 at 18:03 GMT. The last event for the science run was on 09 May 1997 at 23:49 GMT.

An ERV event list and fits format average bias frame for this science run were created from the ACIS telemetry using PSCI. For a description of PSCI and the ERV format (see http://acis.mit.edu/ttools/psci.html).

The ERV format event list was converted to ACIS RV format using an IDL program which combines the fits format average bias file and the E RV format event list. For a description of the ACIS RV format see http://acis.mit.edu/ttools/acis-analysis.html.

To directly compare the telemetry event list with the High Speed Tap event list, events which the telemetry includes but the High Speed Tap does were removed. There are three types of events that the High Speed Tap event list does not include; events on quadrant boundaries, events taken before (22:17 GMT) or after (23:00 GMT) the High Speed Tap data were captured, and events in frames that the High Speed Tap dropped.