XMM-Newton 1 M.Stuhlinger/P.Calderon, ESAC Re-appearance of the MOS1 CCD1 meteorite column during...
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Transcript of XMM-Newton 1 M.Stuhlinger/P.Calderon, ESAC Re-appearance of the MOS1 CCD1 meteorite column during...
XMM-Newton
1
M.Stuhlinger/P.Calderon, ESAC
Re-appearance of the
MOS1 CCD1 meteorite column
during revs. 1792-1801
Madrid, 23. March 2010
XMM-Newton
2
M.Stuhlinger/P.Calderon, ESAC
Review: Initiation
● Presumably micro-meteorite impact into MOS1 in rev. 0961.
Anomaly frame [energy] Subsequent frame [energy]
XMM-Newton
3
M.Stuhlinger/P.Calderon, ESAC
Review: Impact on hardware
● CCD6 inactive.
● Damaged pixels in CCD1 causing hot column close to boresight.602
RAWY
539
11 dead pixels:RAWX 323RAWY 567-577
First diagnostic exposure taken in rev. 0961: CCD1 detail
New hot column RAWX 323:3 (9) pixels next to pn (RGS)prime boresight position
XMM-Newton
4
M.Stuhlinger/P.Calderon, ESAC
Review: Corrective actions
● Investigated meteorite column offset in FF, LW and SW mode diagnostics: • Same increased column offset (by ~19 ADU) measured for all
imaging modes.
● Investigated impact of meteorite column offset for science observations: • Calibration line energies in calclosed observations were shifted
by ~20 ADU.• Similar offset as in diagnostic exposures.• Thus just an additive offset.
● Correction can be done by changing of onboard-offset table to make the meteorite column available for science again.
XMM-Newton
5
M.Stuhlinger/P.Calderon, ESAC
Review: Monitoring of column offset
● Regular FF, LW and SW diagnostic exposures in routine calibration. • Column offset showed exponential long term decay.
● On-board offset table value decreased by 10 ADU (123 =>113 ADU) after ~600 revolutions (active since rev. 1690).
Topic of this talk
XMM-Newton
6
M.Stuhlinger/P.Calderon, ESAC
Re-appearances since on-board offset table change
● Detections usually by Blanca Juárez (last remaining InsCon).
● During first eclipse phase after correction in single observations. (revs.1122-1130).
● Few single observations, e.g. slew 9152300002.
● Short phase in revs. 1537+1538.
Offset in on-board table decreased (~rev.1690).
● After change, column was mostly hot in revs. 1698-1701.
● Longer phase in revs. 1792-1801.
XMM-Newton
7
M.Stuhlinger/P.Calderon, ESAC
Trend during re-appearance in revs. 1792-1802
● Diagnostic exposures to measure the column offset during a “hot phase” are only available for latest occurrence due to coincidence with routine calibration observation in rev. 1796 (Capella).
500 sec bins
XMM-Newton
8
M.Stuhlinger/P.Calderon, ESAC
First diagnostics during re-appearance
● Diagnostics in routine cal. observation 1796-0510780401 (Capella):column offset about 7 ADU higher (119 ADU) than expected by the decay model (112 ADU).
XMM-Newton
9
M.Stuhlinger/P.Calderon, ESAC
Detection due to telemetry anomaly
● Independent notification of hot meteorite column by Pedro Calderon via strange behaviour of MOS1 telemetry, e.g. in rev.1800.
● MOS1 telemetry showed flares whereas MOS2 telemetry was constant.
● Meteorite column is cause of telemetry anomaly.
XMM-Newton
10
M.Stuhlinger/P.Calderon, ESAC
Frequency search in SW obs.1800_0412600801
● Except readout time and its harmonics, no significant frequency was found inside the data.
0.3 s = readout
Harmonics of readout frequency
XMM-Newton
11
M.Stuhlinger/P.Calderon, ESAC
Frequency search in FF obs.1798_0605580601
● Column modulation at long timescales or feature of harmonics?
2.6s = readout
1000 x readout
XMM-Newton
12
M.Stuhlinger/P.Calderon, ESAC
Summary
● If the meteorite column appears hot, it is due to increase of the column offset.
● No time correlation was found for frequencies higher f>0.01 Hz.
● Possible correlations at very low frequencies, might be just features in harmonics of light curve binning/readout frequency harmonics(?).
Still open questions:
● Why does the meteorite column occasionally re-appears hot for some observations / time periods?
● What causes the (short term) variation of the column offset?
XMM-Newton
13
M.Stuhlinger/P.Calderon, ESAC
Future…