README File for CALDB 4.9.3 Upgrade Only Instructions 14 October 2020 DE Graessle, Chandra CALDB Manager Includes brief Intro, Upgrade download and installation instructions, and pointers for further assistance. To learn more about the Chandra CALDB, and to find this information on the WEB, you are referred to http://cxc.harvard.edu/caldb/index.html. For Release Notes to the Chandra CALDB4, and specifically CalDB 4.9.3, see http://cxc.harvard.edu/caldb/downloads/releasenotes.html These instructions apply only to those wanting to upgrade their CalDB version 4.9.0 or later version to version 4.9.3 quickly, installing only the updated calibration files and index updates. You must have installed CalDB 4.9.0 or later version previously, or this upgrade installation will not work correctly. CalDB 4.9.3 is compatible with CIAO 4.12 or later versions only. It is NOT to be used with CIAO 4.11 or any ealier versions of CIAO. Be sure to use the CIAO command "check_ciao_caldb" to verify your CalDB version before proceeding with these instructions. Condensed Release Notes for CalDB 4.9.3 ------------------------------------------------------------------------------------------ I. Introduction CalDB 4.9.3 is an upgrade to the Chandra CalDB, which includes the following items: * ACIS T_GAIN Epochs 77-82 * HRC-I GTI_LIM for HV Ramp-Up Procedure For the CIAO 4.12 / CalDB 4.9.3 release notes see How CalDB 4.9.3 Affects Your Analysis, at https://cxc.cfa.harvard.edu/ciao/releasenotes/ciao_4.12.1_release.html"#HowCALDB4.9.3AffectsYourAnalysis" ------------------------------------------------------------------------------------------ II. SUMMARY OF CHANGES A. ACIS T_GAIN Epochs 77-82 Location: $CALDB/data/chandra/acis/t_gain/ Filenames: acisD2019-05-02t_gainN0008B_revA.fits acisD2019-05-02t_gainN0008_revA.fits acisD2019-11-01t_gainN0008B.fits acisD2019-11-01t_gainN0008.fits acisD2020-05-02t_gain_biN0002.fits acisD2020-05-02t_gainN0002.fits The ACIS Calibration team has released new time-dependent gain correction data from the most recently complweted bi-epochal period, namely Epochs 81+82 (Feb-Jul 2020). With this release it is now possible to finalize the T_GAIN for the previous bi-epochal period (Epochs 79+80, Aug 2019 through Jan 2020). These updates are included in the files above with effecive dates 2020-05-02 (provisional) and 2019-11-01 (finalized) respectively. As with recent previous epochs, the T_GAIN calibration continues to be challenged by the ever poorer statistics available from the ACIS External Calibration Source (ECS), which continues to decline in intensity as expected over time. However, a new data reduction method involving trend evaluation which considers a full year of ECS data to influence ("nudge") the semi-annual results, has produced considerable improvement in the latest data sets. The new technique was applied to the Epochs 77+78 period (Feb-Jul 2019) in addition to the bi-epochal periods above. Hence a "_revA" version of the previously-released 2019-05-02 T_GAIN files, and are listed above as well. This release affects all ACIS observations taken since 2019-05-02T12:00:00, and users of any OBS_IDs with DATE-OBS later than that date are encouraged to reprocess their datasets. The degree of the corrections is similar to those of previous T_GAIN releases, and those analyzing narrow line-source data are the most likely to be affected signficantly. See the technical details section below for further information. See the why page for a more basic explanation of the time-dependent gain correction. PIPELINES/TOOLS AFFECTED: ACIS Level 1 pipeline tool acis_process_events. CIAO script chandra_repro uses acis_process_events to reprocess ACIS observation data. THREADS AFFECTED: Reprocessing Data to Create a New Level=2 Event File B. HRC-I GTI_LIM for HV Ramp-Up Procedure Location: $CALDB/data/chandra/hrc/gti_lim/ Filename: hrciD2020-09-28gti_limN0001.fits The recent HRC power supply anomaly aboard Chandra has required that the detectors be powered down so that the "B-side" electronics could be implemented. Power to HRC was then reestablished successfully, and most recently the HRC-I high voltage settings have been brought back up again. The procedure was completed over 2020-09-28 through 2020-09-29, with a manual procedure to "ramp up" the HV. The HRC instrument team requested that a modified GTI limits file be used for the data taken during the ramp-up procedure so that events could be delivered to L2 despite the GTI limits being applied. The modification was to removed the line from the HRC-I GTI_LIM file which includes the HV limits. A file with that prescription is listed above, and is to be effective in CalDB for only the period of 2020-09-28T00:00:00 until 2020-09-30T00:00:00. PIPELINES/TOOLS AFFECTED: In standard data processing (SDP) only, the tool mtl_build_gti, first run only for the "standard" GTI limits configuration, which is the only case in which the parameter lkupfile is actually set to "CALDB", so that the CalDB GTI_LIM file for HRC-I is actually delivered. THREADS AFFECTED: No CIAO threads are affected by this change. ------------------------------------------------------------------------------------------ III. Instructions for installing the upgrade from CalDB 4.9.0 or later version to 4.9.3. The following are manual installation instructions. You may also download and install CalDB 4.9.3 using the "ciao-install" script at http://cxc.harvard.edu/ciao/download/, or follow the instruction at http://cxc.cfa.harvard.edu/caldb/downloads/index.html. Before you begin, you must have write privileges in your local CalDB area. If you don't have your system administrator do this upgrade! A. As system admin, verify your current CalDB version. With CIAO installed and loaded, enter the command "check_ciao_caldb" If you do not see that the CalDB version is 4.9.0 or later version, you need to use the MAIN CalDB download procedure from Table 1 of the CIAO CalDB downloads page. If the version shown is 4.9.0 or later, proceed with the following: B. Downloading Instructions: Set your working directory to $CALDB, and verify that you are there. Please download the "upgrade" tar ball and either or both of the other tar balls you may need (as indicated below) into the $CALDB area. The following FTP links will allow you to access the files from the Chandra Data Archive. You may also use your web browser to locate the CalDB Download instructions, and proceed from there: http://cxc.harvard.edu/caldb/downloads/index.html CALDB UPGRADE FILE: ftp://cda.harvard.edu/pub/arcftp/caldb/upgrade/caldb_4.9.3_upgrade.tar.gz The ACIS BKGRND files have been updated to include (1) eleven N0002 files in Group G for 2012-01-01 through the present. Some header updates were released as of the with CalDB 4.9.2.1 on 09 Jul 2020. ftp://cda.harvard.edu/pub/arcftp/caldb/acis_bkgrnd_4.9.2.1.tar.gz Three new HRC-I BKGRND files, effective for calendar years 2015-2017 respectively, have been added to the CalDB as of version 4.7.7 (14 Dec 2017). As has been the case since their original addition to CalDB, they are packaged separately in the following tar file: ftp://cda.harvard.edu/pub/arcftp/caldb/hrc_bkgrnd_4.7.7.tar.gz TABLE 1: Files, sizes, and md5sum values: FILENAME Ship Size Unpacking space md5sum (bytes) caldb_4.9.3_upgrade.tar.gz 1,289,044,104 3.3 GB 0804937cdbeabca6a95af435e06c38c2 acis_bkgrnd_4.9.2.1.tar.gz 1,387,254,665 2.9 GB ea9c6dec632d6efae242b426513cc3f4 hrc_bkgrnd_4.7.7.tar.gz 2,323,747,030 3.2 GB 3c9b4e5d6966929793d726b12ae4a4b2 C. Unpacking instructions: We prefer that you use gtar with the appropriate options to unzip and untar the files in a single step, to save disk space and to apply the safest unpacking procedures: gtar xvUfz caldb_4.9.3_upgrade.tar.gz gtar xvfz acis_bkgrnd_4.7.6.tar.gz gtar xvfz hrc_bkgrnd_4.7.7.tar.gz LINUX users: You may omit the "U" uption in the first gtar command. D. Upgrade verification checks See the CalDB downloads web page for steps to verify your upgrade installation, at http://cxc.harvard.edu/caldb/downloads/index.html#dl_config. - Dale Graessle Chandra CalDB Manager