CalDB Public Release Notes Version 2.28 Effective Date: 2004-08-11T17:00:00 Released in Processing: 2004-08-11T19:30:00 I. Summary of Changes A. ACIS QE version 5 / QE Uniformity (QEU) -120C version 2 Location: $CALDB/data/chandra/acis/bcf/qe/ Filenames: acisD1997-04-17qeN0005.fits acisD2000-01-29qeuN0002.fits In tandem, these new files improve the local QE estimates for seven of the ten ACIS chips. The first file contains a modification of the so-called mean QE for chips ACIS-5 and -7 only (the back-illuminated chips). The second contains new QEU maps, correcting for the QE loss due to CTI effect, for all but chips ACIS-4, -8, and -9. Users may want to look over the QE Comparison "Why" page at http://cxc.harvard.edu/ciao/why/qeu.html for information regarding how this change would affect their analyses. Tools affected: CIAO mkarf, mkgarf, mkexpmap (mkinstmap), mkwarf for ACIS data only Threads affected: 1. Exposure map threads: http://cxc.harvard.edu/ciao/threads/expmap_acis_single/ http://cxc.harvard.edu/ciao/threads/expmap_acis_multi/ 2. ARF threads: Arfs for point sources "psextract" and pieces thereof: http://cxc.harvard.edu/ciao/threads/psextract/index.html#script http://cxc.harvard.edu/ciao/threads/pieces/index.html#arf 3. GARF threads; ACIS/grating combinations: Compute HETG/ACIS-S Grating ARFs http://cxc.harvard.edu/ciao/threads/mkgarf_hetgacis/ Compute LETG/ACIS-S Grating ARFs http://cxc.harvard.edu/ciao/threads/mkgarf_letgacis/ 4. Weighted ARFs for ACIS (mkwarf): Weighting ARFs and RMFs: multiple sources http://cxc.harvard.edu/ciao/threads/wresp_multiple_sources/ Extracting Extended Source Spectra and Responses http://cxc.harvard.edu/ciao/threads/acisspec_extract/ B. LETG Grating Efficiency Version 5 Location: $CALDB/data/chandra/tel/grating/letg/bcf/greff/ Filename: letgD1999-07-22greffpr001N0005.fits This file gives an improved estimate of the LETG grating efficiencies at certain higher-orders, namely: +/-2, +/-4, +/-5, +/6, and +/-7. It was derived using the new ACIS QE/QEU above, and hence must be upgraded in tandem therewith. Note that the first and third order grating efficiencies have NOT changed. Tools affected: CIAO:mkgarf for LETG observations. Threads affected: Compute LETG/ACIS-S Grating ARFs http://cxc.harvard.edu/ciao/threads/mkgarf_letgacis/ Compute LETG/HRC-S Grating ARFs http://cxc.harvard.edu/ciao/threads/mkgarf_letghrcs/ C. LETG/ACIS-S LSF Parameter files (with RAND_TG=0.0) Location: $CALDB/data/chandra/tel/grating/letg/cpf/lsf/ Filenames: acissleg-1D1999-07-22lsfparmN0003.fits acissleg1D1999-07-22lsfparmN0003.fits These files complete the set of LSFPARMs for the new processing case, where the transmission grating pixel randomization is switched to OFF. The files are selected whenever the keyword RAND_TG is present and set to 0.0 in the PHA2 and EVT2 file headers. Since the installation of DS 7.3.x, this has been the default condition. Tools affected: CIAO: mkgrmf Threads affected: Create Grating RMFs for ACIS-S Observations (LETG/ACIS-S case) http://cxc.harvard.edu/ciao/threads/mkgrmf_aciss/ D. HRC-S BADPIX version 3 Location: $CALDB/data/chandra/hrc/bcf/badpix Filename: hrcsD1999-07-22badpixN0003.fits This new file has a time-dependent addition for a rectangular hot spot on plate 1 of HRC-S, which recently became enlarged. Tools affected: HRC L1 pipeline: hrc_build_badpix Does NOT affect CIAO at all. Threads affected: NONE. E. Corrections to HRC-I/S GTI_LIM secondary pipeline files, version 6 Location: $CALDB/data/chandra/hrc/bcf/gtilim/ Filenames: hrciD1999-07-22gtilim_secN0006.fits hrciD1999-10-04gtilim_secN0006.fits hrcsD1999-07-22gtilim_secN0006.fits These files have some extraneous lines accidentally added to the previous version N0005 files released with CalDB 2.27. The secondary pipeline does not run for science data, and does not affect users. The secondary pipeline runs for engineering data only, such as for monitoring of certain spacecraft systems or certain on-board calibrations. Tools affected: Secondary L2: mtl_build_gti Threads affected: None. F. ACIS GAIN FILE INDEX MODIFICATIONS: Filenames: acisD1999-07-22gainN0002.fits (FP_TEMP = -90C) acisD1999-08-13gainN0002.fits (FP_TEMP = -100C) Directory: $CALDB/data/chandra/acis/bcf/gain/ Change to -100C and -90C ACIS gain file listings. Added the boundary condition CBD30001='CTI_CORR(NO)' to both of these listings, so that these files would not be selected by acis_process_events for cases where the CTI corrector is turned ON. This was in response to a helpdesk ticket wherein a_p_e was getting the correct -110C gain file when the CTI-corr was turned off, and another (-100C) when it was accidentally turned ON. This was later identified as an error in the sequencing of CalDB calls within a_p_e wherein the CTI corrector was ON by default at the start. Hence, a CTI_CORR.EQ.YES was given by default in the ACIS gain lookup. Then when a_p_e discovered no CTI corrector file for the -110 C data, it reset this to CTI_CORR.EQ.NO, but too late for the gain call. This problem will be repaired in the CIAO 3.2 release. In CIAO 3.1, using acis_process_events on -110C data with the default CTI setting will produce an error wherein a_p_e can't find a suitable gain file. For CIAO 3.1 users, any data taken at -110C, -100C, or -90C should be reprocessed by presetting the appropriate a_p_e parameter as follows: pset acis_process_events apply_cti=no This will ensure that you get the appropriate gain file rather than an error. Threads affected: ACIS DATA PREPARATION: Apply an ACIS Gain Map http://cxc.harvard.edu/ciao/threads/acisgainmap/ Apply the ACIS CTI Correction http://cxc.harvard.edu/ciao/threads/acisapplycti/ II. Technical details A. ACIS QE v5 / QEU version 2 (-120C) Discrepancies between measured fluxes from ACIS-I and ACIS-S imaging observations have been documented from early in the Chandra mission. In the process of diagnosing this discrepancy, several issues were uncovered with the ACIS QE determination, and in particular two issues surfaced with respect to calibration files: 1) the BI chips QE correction, and 2) QEU normalization. We have corrected issue 1 and clarified and corrected issue 2 above. Also with regard to the QEU, we have accumulated considerable ECS data over the years, and are now able to provide a calibration with considerably more spatial detail, incorporating a far greater understanding of how the CTI affects the local QE for seven of the ten chips. (Chips 4, 8, and 9 have not been upgraded; instead the same data as in -120C qEU version 1 have been carried over.) The correction to S1 and S3 QE's proper is presented in the following memorandum: http://cxc.harvard.edu/cal/Acis/Cal_prods/qe/qe_memo.ps, "Absolute QE of ACIS S1, S2, and S3 from XRCF data at selected energies" The above memorandum is visible from the link http://cxc.harvard.edu/cal/Acis/Cal_prods/qe/index.html, where and abstract may be found. The ACIS QEU upgrade is presented in full detail in the memorandum http://cxc.harvard.edu/cal/Acis/Cal_prods/qeu/qeu.pdf, "High Resolution QEU maps for ACIS-I and S1,2,3 chips", which is visible from the link: http://cxc.harvard.edu/cal/Acis/Cal_prods/qeu/index.html Users may want to look over the QEU Comparison "Why" page at http://cxc.harvard.edu/ciao/why/qeu.html for information regarding how this change would affect their analyses. NOTE: The definition of the QE and QEU respectively are now that the actual QE values for each chip in the file are the QE's associated with the near-readout position of the chip. Hence the QEU is normalized to unity at these points. The QEU tables then degrade this QE value with increasing CHIPY. B. LETG Grating Efficiency version 5 For technical details you are refered to the LETG Calibration page http://cxc.harvard.edu/cal/Letg/HO2004/ An improved calibration of certain LETG higher order (m=2, 4, 5, 6, and 7) efficiencies has been completed, based on ACIS QE version 5 and QEU -120C version 2. The first and third order efficiencies have not changed. Hence, a new LETG grating efficiencies file has been generated and tested for the Chandra CalDB. The updated orders are also updated symmetrically for positive and negative corresponding orders. C. LETG/ACIS-S LSFPARMS +/-1st order, RAND_TG=0.0 The final set of line-spread-function LSF parameter files, these for the LETG/ACIS-S configuration, have been generated, specifically two files, one for +1 order and the other for -1 order. As with the other grating/instrument configurations, the transmission grating pixel randomization has been turned off (corresponding to keyword RAND_TG value set to 0.0 pixels) in DS version 7.3.0+, and will be turned off for REPRO 3 as well. Hence ALL top-level archival data and any new processing will have no TG pixel randomization. This change requires that LSF parameters be recalculated for the RAND_TG =0.0 case. This has been done for the HETGS and LETGS cases in CALDB 2.27, released July 7, 2004. A memorandum with further information may be found at http://space.mit.edu/CXC/docs/docs.html#lsf3 D. HRC-S BADPIX version 3 From Frank Primini: HRC-S plate 1 includes a hot spot previously identified (see the current HRC-S badpix file, version 2) but which has grown in size as of date TT= 122597337.0 seconds. The new rectangle specification line has been added to the existing fits file to make version 3 of the HRC-S badpix file as follows: ROW SHAPE COMPONENT RAWX[2] RAWY[2] TIME STATUS EXISTING: 12 RECTANGLE 1 [2964 2974] [27740 27750] [122597337.0 NaN] 00100000 NEW ROW: 13 RECTANGLE 1 [2960 2975] [27731 27750] [192105457.0 NaN] 00100000 Note that the new row 13 specifies a rectangle that subsumes the rectangle in row 12. There is a time-dependence to these rows such that the software may use only the portion that is required during the time between TT=122597337.0 and 192105457.0 seconds. E. HRC-I/S GTI_LIM secondary pipeline file corrections, version 6 We must inform the CCB that an error has been found (by inspection, not by processing error diagnostics) that the recently upgraded GTI_LIM files for the secondary pipeline cases of HRC-I and HRC-S include about 25 spurious lines of limits that are not applicable to the secondary pipeline specifications, along with the five lines of limits required for that pipeline. Needless to say this eluded both pipeline processing scientist Ian Evans and the CalDB Manager at the time preceding installation. Duty scientist Dong-Woo Kim discovered this irregularity upon inspection of results of successful secondary pipeline processing of three OBSIDs, (namely 62979, 62980, and 62983) wherein all events were excluded from good time intervals because the HV limits of the HRC-S were violated for them. In other words, the GTI_LIM files worked correctly in these cases, but were still found to have extraneous lines of limits in them. Note that the processing for the three OBSIDs mentioned actually completed successfully. Ian Evans has stated that these extraneous lines of limits ought to be removed from the CalDB (that is, these current files should be upstaged by new ones without the errant extraneous data) because there is a clear possibility that circumstances could arise where they would be a problem. These files would NEVER affectscience observations, because they are never used for the SI pipelines, only the secondary pipeline. Engineering Run (or "ER") observations might be adversely affected by the extraneous GTI limits included. Therefore we request the included change, and acknowledge our error in the previous release.