*** Disregard. The acis_build_chip_gti specs are flawed. ***
This document describes a specification for the ACIS tool acis_build_chip_gti.
This document describes a specification for the ACIS tool acis_build_mask.
This document describes a specification for the ACIS tool acis_detect_hotpix. This spec is superseded by the newer afterglow and hot-pixel detection spec.
Afterglow and hot-pixel spec
This document describes a specification for the ACIS tool acis_make_bkgd.
This document describes an incomplete specification for the ACIS tool acis_process_events.
This document describes the use of the parameters bitflag and usrfile for the tool acis_build_badpix.
ACIS Analysis Reference Data Interface Control Document
This document describes the formats of the Analysis Reference Data files used by the ACIS tools.
This spec describes how to handle bias-parity errors when producing a bad-pixel file.
Bias repair and replacement
This spec describes how to repair or replace a bias for an observation with a suitable bias from another observation.
Check VFAINT background
This document describes an algorithm that can be used to search for potential cosmic-ray background events in the data for TIMED VFAINT mode observations.
This document describes how to compute the CTI-adjusted values of PHAS, PHA, ENERGY, PI, FLTGRADE, and GRADE for ACIS event data. The algorithm includes a temperature-dependent scaling factor for the integrated trap-density maps.
This document describes the algorithm used to identify anomalous DELTOCLK values.
Computation of FLTGRADE, GRADE, and PHA
This document describes how to compute FLTGRADE, GRADE, and PHA for ACIS event data.
Download PS (280 K) of Rev. 1.1 (04/02/99)
Computation of X, Y, and TIMEs of arrival of CC-mode events
This document describes how to compute the sky coordinates and times of arrival of photons at the detector for CC-mode event data.
Download PS (1.7 M) file of Chandra Calibration Workshop presentation, November 2002 (11/07/02)
ACIS Level 0 Interface Control Document
This document describes the formats of the Level 0 data products.
Download older revisions of the ICD
ACIS Level 1 Interface Control Document
This document describes the formats of the Level 1 data products.
Download older revisions of the ICD
This document describes a specification for computing observation-specific biases from mean biases.
ACIS pipeline processing caveats
This document describes caveats about ACIS pipeline-produced event data.
S4 streak algorithm
This document describes an algorithm used to identify horizontal, instrumental, streak events on ACIS-S4.
Download PDF (1574 K) of the August 1, 2000 document (06/07/13)
S4 streak loss parameter
This document describes a better implementation of the fractional loss parameter of the tool that identifies horizontal, instrumental, streak events on ACIS-S4.
Download PDF (2640 K) of Rev. 1.1 (06/12/13)
Download PDF (2594 K) of Rev. 1.0 (06/10/13)
S4 streak properties
This document describes the properties of the horizontal, instrumental, streak events on ACIS-S4.
Download PDF (328 K) of the March 16, 2004 document (06/07/13)
STATUS bits in bad-pixel files
This document describes the conditions for which the STATUS bits in ACIS bad pixel files are set.
STATUS bits in event files
This document describes the conditions for which the STATUS bits in ACIS event data files are set.
Sub-pixel event-repositioning and pixel randomization spec
This document is a spec describing the sub-pixel event-repositioning and pixel randomization algorithms.
Time-dependent gain spec
This document specifies how to apply the time-dependent gain adjustment. This spec is superseded by the acis_process_events spec.
This memo describes changes made to acis_process_events and tg_resolve_events which improve order-sorting through a second pass of processing which uses the HETG-processing-determined CHIPY position to re-do CTI/gain/tgain corrections.
Current version: PDF Ver. 1.0 (04 Nov 2015)
Tests/validation of new HRC-S QE and LETG EEFRAC
This memo shows test of the revised HRC-S QE and LETG EEFRAC (in the LSFPARM file). The LETGS effective area should be unchanged. EEFRAC changes were required for custom extractions which can improve a weak lines signal-to-noise ratio.
Current version: PDF Ver. 1.0 (11 August 2015)
HRC-S Tgain correction (for reduced background); LETG/HRC-S spectral filtering after HRC-S Tgain correction
This document describes the HRC-S time-dependent linearized PI computation ("SPI") for background reduction and associated CALDB "t_gmap" file (appropriate for all HRC-S observations), and the associated HRC-S/LETG event filter required for spectral extraction from Tgain-corrected HRC-S events (CALDB "pireg_tgain" file).
Current version: PDF Ver. 1.4 (24 November 2009)
Previous version: PDF Ver. 1.3 (8 July 2009)
Technical Note: LETG/ACIS-S rotation compensation
Modification to extraction region to compensate for anomalous rotation residuals.
Data Randomization / New Header Keywords
This document describes how we propose to implement additional FITS keywords into Level 1 Event products and higher.
Interface Control Document describing the reference data read by exposure map and gratings pipelines and tools.
ACIS Spatial Contamination (2004.10.13 UPDATE)
ACIS Dead Area (2006.09.14 update)
ISIS: Interactive Spectral Interpretation System
resolution X-ray spectra (currently under development).
Download PS ..... (392 K)
Talk by John E. Davis, from CXC S-Lang class (January, 2003)
AXAF Transmission Grating Diffraction Coordinates
to dispersion coordinates.
Download PS ..... (101 K)