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CalDB PUBLIC Release Notes
Effective Date: (UTC) 2007-02-02T14:00:00
Public Release Date: 02 February 2007
Version: 3.3.0.1
Release Type: PUBLIC only
 

I. Introduction

CalDB 3.3.0.1 is an emergency patch to CalDB 3.3.0 (released 18 Dec 2006) which includes a correction to the ACIS branch index file located at $CALDB/data/chandra/acis/caldb.indx. The correction is a change to the boundary conditions of the four FEF_PHA listings. The FEF_PHA files are the inputs to the CIAO tool "mkrmf". The change allows the -120C CTI-corrected FEF file to be selected properly in "acis_fef_lookup" for data processed by ASCDSVER DS 7.6.10 or later.

CalDB 3.3.0.1 is a public release version, and does not affect Standard Data Processing in any way.

II. Summary of Changes

A. ACIS FEF_PHA file header updates/index listing changes
Files affected:
acisD2000-01-29fef_phaN0005.fits (FP_TEMP=-120C, CTI_CORR=NO)
acisD2000-01-29fef_pha_ctiN0004.fits (FP_TEMP=-120C,CTI_CORR=YES)
Location: $CALDB/data/chandra/acis/cpf/fefs/

The CXC CalDB Manager has discovered an error in the CalDB 3.3.0 ACIS branch index file, which prevents the tools from selecting the CTI-corrected FEF_PHA file (acisD2000-01-29fef_pha_ctiN0004.fits) for data reprocessed with acis_process_events in CIAO 3.4 or in DS 7.6.10, or later versions of the software. CIAO 3.4 was released on 18 Dec 2006, and DS 7.6.10 was installed on 09 Jan 2007. Data processed or reprocessed by earlier versions of either software are NOT AFFECTED by this error.

The error only affects users with all three of the following circumstances:
- Using data reprocessed with acis_process_events in CIAO 3.4 or later, or processed in DS 7.6.10 or later
        at the CXC SDP Operations Center.
AND
- The data has the CTI correction applied, that is, is not a GRADED DATAMODE observation.
AND
- Using "mkrmf" and "acis_fef_lookup" to select the ACIS -120C CTI-corrected FEF_PHA file,
        acisD2000-01-29fef_pha_ctiN0004.fits automatically from the CalDB. Users of the tool mkwarf, or the
        scripts "acisspec" "psextract" are included in this description.

Here is an example of a user, whose circumstances meet the above criteria, attempting to call for a FEF_PHA file using acis_fef_lookup with CalDB 3.3.0:
dagny-12: punlearn acis_fef_lookup
dagny-13: dmkeypar acism05511_chipi3_evt2.fits CTI_APP echo+
PPPPPBPBPP
dagny-14: acis_fef_lookup acism05511_chipi3_evt2.fits chipid=3 chipx=512 chipy=512
# caldb (CIAO 3.4): WARNING:  2 CALDB files found. Using the first

/data/CALDB/ciao/data/chandra/acis/cpf/fefs/acisD2000-01-29fef_phaN0005.fits[FUNCTION][ccd_id=3,chipx=257:512,chipy=481:512]

The warning results from the caldb search routine "quizcaldb" being unable to distinguish between the two -120C FEF_PHA files on the basis of CTI_APP, because neither file specifies this boundary condition currently. Furthermore, because the non-CTI FEF file comes first in the index listing, it gets selected by default, even though it is the wrong file.

acis_fef_lookup works correctly for a newly reprocessed dataset that wants the CTI-corrected FEF in CalDB 3.3.0.1:

dagny-15: punlearn acis_fef_lookup
dagny-16: dmkeypar acism05511_chipi3_evt2.fits CTI_APP echo+
PPPPPBPBPP
dagny-16: acis_fef_lookup acism05511_chipi3_evt2.fits chipid=3 chipx=512 chipy=512
/data/CALDB/test_2/data/chandra/acis/cpf/fefs/acisD2000-01-29fef_pha_ctiN0004.fits[FUNCTION][ccd_id=3,chipx=257:512,chipy=481:512]

This time, the correct FEF_PHA is selected.

From E. Galle on 30 January 2007, testing acisspec:

The warning results from the caldb search routine "quizcaldb" being unable to distinguish between the two -120C FEF_PHA files on the basis of CTI_APP, because neither file specifies this boundary condition currently. Furthermore, because the non-CTI FEF file comes first in the index listing, it gets selected by default, even though it is the wrong file.

The headers and more importantly the index listings of the above listed FEF_PHA files have been enhanced to correct this error in the 3.3.0.1 patch. Specifically, the tool "acis_fef_lookup", employed by hand or internally in the threads "psextract" and "acisspec", will now select the CTI-corrected FEF_PHA file for -120C operating temperatures (acisD2000-01-29fef_pha_ctiN0004.fits) rather than errantly selecting the corresponding non-CTI-corrected FEF_PHA file (acisD2000-01-29fef_phaN0005.fits).


Users are alerted to check their analysis of data files processed in CXC Standard Data Processing since 09 January 2007, or reprocessed using CIAO 3.4 acis_process_events, wherein the CTI-correction has been applied, if they are using "mkrmf", "acis_fef_lookup", or scripts "acisspec" or "psextract".

CIAO tools/scripts affected:
mkrmf, acis_fef_lookup, acisspec, psextract, mkwarf

CIAO Threads affected:
"Using psextract to Extract ACIS Spectra and Response Files for Pointlike Sources"
http://asc.harvard.edu/ciao/threads/psextract/
"Coadding Spectra and Weighted Responses"
http://asc.harvard.edu/ciao/threads/acisspec_coadd/
"Weighting ARFs and RMFs: multiple sources"
http://asc.harvard.edu/ciao/threads/wresp_multiple_sources/ (if user does not elect to use mkacisrmf)
"Step-by-Step Guide to Creating ACIS Spectra for Pointlike Sources"
http://asc.harvard.edu/ciao/threads/pieces/ (if one elects to use mkrmf and acis_fef_lookup)

II. Technical Details

A. ACIS FEF_PHA files

The ACIS FEF_PHA files are used as input to the CIAO tool mkrmf to generate ACIS response matrix files (RMFs). The boundary condition which allowed the selection of CTI versus non-CTI FEFs has been stored in the keyword CBD60001, which sets the CTI_CORR value to either YES for the CTI-corrected data, and to NO for non-cti-corrected data.

With the advent of CIAO 3.4, CalDB 3.3.0, and DS 7.6.10, the CTI_CORR parameter has been replaced by the new keyword CTI_APP. This new parameter has a 10-character specification, with each character place denoting a particular ACIS chip. CTI_APP may have one of three values:

CTI_APP:         CTI-correction applied        FEF_PHA to be selected
---------------------------------------------------------------------
NNNNNNNNNN      No CTI correction applied     non-CTI-corrected FEF_PHA
PPPPPNPNPP      CTI-correction for FI chips   CTI-corrected FEF_PHA
PPPPPBPBPP      CTI-correction for all chips  CTI-corrected FEF_PHA

The FEF_PHA library of files has most recently been updated as of November 2004. While the FEFs remain part of the CalDB, the library will not be upgraded any further, now that "mkacisrmf" has been added to CIAO, and the phase 2 response files (P2_RESP) have been included in the CalDB. Current and future changes to the ACIS RMFs will be maintained in the P2_RESP files, but not in the FEF_PHA files.

The -120C CTI-corrected FEF_PHA file (acisD2000-01-29fef_pha_ctiN0004.fits) only contains the appropriate CTI-corrected response inputs for the ACIS-I array chips. The response data for ACIS-7 (ACIS-S3) when NOT CTI-corrected are also acceptable for processing since November 2004. However, the included data for ACIS-4,5,6,8, and 9 are totally out of date for the CTI-corrected forms of these data, and must never be used. Instead users must use "mkacisrmf" and the appropriate P2_RESP file as input, for their particular CTI-correction configuration (CTI_APP value set by acis_process_events).

Users of -120C GRADED DATAMODE datasets must still employ the non-CTI-corrected FEF_PHA file (acisD2000-01-29fef_phaN0005.fits) for analysis of FI chips data. For the ACIS-S1 chip, users must use mkacisrmf to employ the gain function compatible with that already applied, for data processed since November 2005, when the new ACIS-S1 gain function was installed in processing. This will include the whole -120C ACIS archive, as it has been recently reprocessed in Repro III. For ACIS-S3, GRADED DATAMODE users may continue to employ the FEF_PHA file, but are strongly encouraged to switch to mkacisrmf to take advantage of the recent upgrades to the response function for S3.

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