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Status of EPIC time jump problems

Status of EPIC time jump problems. Marcus G. F. Kirsch, M.J. Freyberg, E. Kendziorra, U. Lammers. Time jumps. mid-2000 first discovered pn-AUX data anomalies: frequency of occurrence is variable unrelated to camera mode, observing time or duration

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Status of EPIC time jump problems

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  1. Status of EPIC time jump problems Marcus G. F. Kirsch, M.J. Freyberg, E. Kendziorra, U. Lammers

  2. Time jumps • mid-2000 first discovered pn-AUX data anomalies: • frequency of occurrence is variable • unrelated to camera mode, observing time or duration • some data sets are completely free of any problems others are heavily affected. • reason: H/W problem of EPEA • consequences: event times turn out wrong • single shift in FTCOARSE time will cause all subsequent times to be wrongly shifted by the same amount. • pulse profile analyses inconclusive because all photons after the instant of the time jump will be out-of-phase • pulse peak broadening, phase shift or the appearance of spurious pulse components. • SAS should find and correct those time jumps

  3. Situation 5.4.1 • Not all negative or positive jumps in FTCOARSE are found and corrected by SAS pulse peak broadening, phase shift spurious pulse components

  4. Experimenting with the detection algorithm: 2-tests 01537503010153750401 0153750501 deltrack deltrack deltrack 6.0 6.0 6.0

  5. Relative Timing accuracy

  6. Status: SAS 6.0 • fast modes: • problems are reliably found and corrected • only 2 know problem cases • imaging modes: • rare cases of very long time jumps (ks) in the imaging modes (< 0.5 %) • still uncorrected time gaps with no integer multiple of frame time (< 2 %) mainly in revs < 220 • list of problematical cases and work around will be provided in document:XMM-Newton EPIC photon arrival times: This document gives an overview of the readout of the EPIC camera and the applied correction to the photon arrival times.

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