CalDB Public Release Notes Version: 3.0.3 (patch) Effective Date: 2005-05-08T16:00:00 CalDB 3.0.3 (patch) contains only one additional new file beyond the most recent version 3.0.2. However the last public release of the CalDB was version 3.0.1, in Feb. 2005. Hence, the public release of CalDB 3.0.3 includes the 3.0.2 patch as well. See the release notes of 3.0.2 for details on that upgrade. I. Summary of Changes: A. ACIS phase 2 response file repaired (p2_resp) Filename: acisD2000-01-29p2_respN0003.fits Location: $CALDB/data/chandra/acis/cpf/p2_resp/ We have discovered an incompatibility between the mkacisrmf software and the currently released p2_resp file (CalDB 3.0.0, December 2004), namely acisD2000-01-29p2_respN0002.fits. The problem exists in Block 4 of the file, the CTI-induced scattering matrices for the FI chips. Specifically there are 21 regions (tiles) of the ACIS front illuminated chips that have data that has not been sorted in increasing PHACHAN order. The result of this is that on these 21 tiles, an RMF with zero values over most of the bandpass will be generated. For individual tiles, the zero RMF will yield obviously bad fitting results; however for weighted RMFs where a WMAP is employed, the result is less obvious, because the amplitude of the resulting RMF will be to some degree reduced. In forward fitting of the response to observation spectra, the result is an overestimate of the source flux for any given model. The new file, version N0003, contains the same data points as the old one, but for the 21 tiles, the PHACHAN sorting has been corrected. For most of these tiles, the RMF will now be acceptable below 10 keV, but will be truncated above that value. In a future release of the CalDB, a new p2_resp file will be included that contains a broader grid, and will use the same grid for all tiles of ACIS. Threads affected: Creating ACIS RMFs with mkacisrmf http://cxc.harvard.edu/ciao/threads/mkacisrmf/ II. Technical Details: A. ACIS p2_resp version N0003 The 21 tiles with the mis-sorted scattering matrix data are as follows: REGNUM CCD_ID chipx_lo chipx_hi chipy_lo chipy_hi 7 0 1 256 193 224 18 0 1 256 545 576 30 0 1 256 929 960 39 0 257 512 193 224 93 0 513 768 897 928 144 1 1 256 481 512 146 1 1 256 545 576 221 1 513 768 897 928 272 2 1 256 481 512 274 2 1 256 545 576 295 2 257 512 193 224 349 2 513 768 897 928 400 3 1 256 481 512 402 3 1 256 545 576 423 3 257 512 193 224 477 3 513 768 897 928 528 6 1 256 481 512 530 6 1 256 545 576 551 6 257 512 193 224 573 6 257 512 897 928 605 6 513 768 897 928 The only way a user can identify if any of these regions is included in their RMF calculation is by watching the standard output of mkacisrmf, or by using the logfile option, and checking this for any of the above region numbers. The CAVEAT for this has been posted on "mkacisrmf bugs" at http://cxc.harvard.edu/ciao3.2/bugs/mkacisrmf.html#sorterr The CXC has elected to do an emergency patch of the CalDB to alleviate this problem as soon as possible. Note that this repair does NOT fix the SEGV problem that occurs on Chip I1, Node 1 for the entire node. That problem requires a patch to the mkacisrmf software, currently anticipated for release in June 2005.