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SAG+SASWG Meeting Potsdam 2006-11-14/15 PN Tasks – Status Report (update since Leicester) Hermann Brunner - MPE epframes: The dark quadrant problem in small number of observations event time vector stops while exposure vector continues => one or several `dark´ image quadrants not correctly represented in exposure maps machine-dependent: ok on Tru64 (32/64 bit issue ?) workarounds: - keyword OBT_WARN to identify affected exposures ( InvalidObtValue warning) - task parameter withallobtgti to adjust GTI to make images and exposure maps consistent - check for NaNs in „all good AUX1 entries“ loop
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SAG+SASWG Meeting Potsdam 2006-11-14/15 do i = 1, ngaux1-1 if (aux1Gtime(i).EQ. aux1Gttime(i) ) then... consistency with hardware where the problem did not occure ?? task uploads should be made by the task author or with the consent of the task author Question on version numbers patch level uploads should not contain interface changes for DEPEND mechanism to work (?) (counter-)example: oal 3.114.1 -> oal 3.114.2 new feature: OAL_hasconfIPPV( )
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SAG+SASWG Meeting Potsdam 2006-11-14/15 merge: now merges both STDGTI and GTI to permit merging of individual flare screened event sets permit merging of arbitrary numbers of event files (current version merges two event files) CAUTION: merged event files don‘t work with all SAS tasks ! epatplot: missing axis labels on some arcitectures but not on others (different pgplot libraries ? – ongoing analysis) epchain: corrected error when running epchain for specific exposures in odfacess=oal mode (SPR closed)
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SAG+SASWG Meeting Potsdam 2006-11-14/15 epreject - ongoing activities: - define new pn event flags BELOW_THRESH flag bit 26 LOEN_NOISE flag bit 27 and include in EPN_REJECTION_MASK purpose: - exclude events shifted below threshold from pattern recognition ( BELOW_THRESH ) - replacement for NOISE column ( LOEN_NOISE ) discussed with CG – SCR to ssclib issued
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- replace noise screening method with different method current method: noise properties derived from calclosed obervations - problems: may cause discontinuities in soft spectrum of weak sources new method: remove noisy frames (more than one event per frame below 31 ADU) and perform statistical noise flagging based on observation itself (calclosed noise-maps not needed anymore) - problem: spectral analysis – interface to arfgen new event table extension: noise ratio image/vector ?? SAG+SASWG Meeting Potsdam 2006-11-14/15
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23.2 ks closed FF 0500 3 application of the original method (implemented in the SAS task epreject) Konrad Dennerl, EPIC Cal meeting, Mallorca, ct. 2006
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EPIC-pn detector noise (LW) 2050 adu 99% suppression Original method (“method 1”): Suppression of events below 50 adu according to a reference noise distribution deduced from long calclosed exposures Shown in blue is the result of this method applied to a (long) calclosed exposure, to illustrate the effect on a very faint X-ray source
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SNR 1E 0102, rev 803, LW, thick, 30 ks =+ singles, 20 – 30 adu, all frames singles, 20 – 30 adu, frames with more than 1 event below 31 adu per frame and CCD singles, 20 – 30 adu, frames with 1 event below 31 adu per frame and CCD
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number of frames removed original number of frames percentage of frames removed removing frames with more than 1 event below 31 adu per CCD and frame: SNR 1E 0102, rev 803, LW, thick, 30 ks
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singles, 0.3-3.0 keV mask for source regions to be avoided for noise determination source region mask SNR 1E 0102, rev 803, LW, thick, 30 ks In order to determine the noise properties, some areas have to be ignored:
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common fit (for all CCDs) between 40 and 100 adu Deriving the general properties of the detector noise from closed exposures
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SNR 1E 0102, rev 803, LW, thick, 30 ks, source regions included red: data set to be corrected, blue: closed exposure
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average 45-55 adu flux SNR 1E 0102, rev 803, LW, thick, 30 ks, source regions excluded
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extrapolated flux at 20 adu averaged between all CCDs SNR 1E 0102, rev 803, LW, thick, 30 ks, source regions excluded
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spectrum before/after noise suppression, source regions excluded SNR 1E 0102, rev 803, LW, thick, 30 ks, source regions excluded
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unfiltered data singles, 25 adu after noisy frame removal SNR 1E 0102, rev 803, LW, thick, 30 ks
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after noisy frame removal singles, 25 adu after spatially uniform noise suppression
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SNR 1E 0102, rev 803, LW, thick, 30 ks after noisy frame removal singles, 25 adu after spatially variable noise suppression
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unfiltered data singles, 30 adu after noisy frame removal SNR 1E 0102, rev 803, LW, thick, 30 ks
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after spatially uniform noise suppression singles, 30 adu after spatially variable noise suppression SNR 1E 0102, rev 803, LW, thick, 30 ks
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singles, 100-130 eV original data after noisy frame removal and spatially uniform noise suppression after noisy frame removal and spatially variable noise suppression
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SNR 1E 0102, rev 803, LW, thick, 30 ks singles, 130-140 eV original data after noisy frame removal and spatially uniform noise suppression after noisy frame removal and spatially variable noise suppression
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SNR 1E 0102, rev 803, LW, thick, 30 ks singles, 140-150 eV original data after noisy frame removal and spatially uniform noise suppression after noisy frame removal and spatially variable noise suppression
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SNR 1E 0102, rev 803, LW, thick, 30 ks singles, 150-200 eV original data after noisy frame removal and spatially uniform noise suppression after noisy frame removal and spatially variable noise suppression
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SNR 1E 0102, rev 803, LW, thick, 30 ks singles, 200-300 eV original data after noisy frame removal and spatially uniform noise suppression after noisy frame removal and spatially variable noise suppression
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Todo list: epreject: new treatment of noise screening, possibly split in separate tasks for offset correction and noise screeing epframes/epevents: internal interface change after solution of OAL time jump problem epexposure: randomisation of event times (after solution of OAL time jump problem) calpnalgo: implement/calibrate mode dependent temperature gain corrections – may require calpnalgo/CCF changes SSC Consortium Meeting Potsdam 2006-11-14
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