- pcagainset:
This tool has been modified to work with a revised EDS gain/offset calibration file. The EDS gain and offset values are needed for all PCA/EDS data configurations except Good Xenon and Standard-2. It is called automatically by the script pcarsp.
The revised calibration file now collects all of the gain/offset values for the mission into separate extensions of a single physical file instead of being in separate files. Pcagainset now reads this single file and determines the extension containing the EDS gain and offset values appropriate for the date of the observation. The current revised file, edsgcor_e04v00.fits, will be available in both the calibration subdirectory in the xte mission database and in caldb
in /caldb/data/xte/pca/bcf/eds. Note that pcagainset will work properly with the older files, but the user may get warning messages.
- edsgcor_e04v00.fits:
This calibration file replaces the previous files devoted to the EDS gain/offset calibration values. As described above, the ftool pcagainset has been modified to read a single file and determine the extension containing the EDS gain/offset values for the date of the observation.
Note that this is a change in the design of the calibration file only and not in any of the EDS gain/offset values.
The location for the file, which can be copied via anonymous FTP at heasarc.gsfc.nasa.gov, is
/caldb/data/xte/pca/bcf/eds.
- PCA Collimator Cubes:
The collimator cubes have had their lower energy bound extended from 2.0 keV to 0.0 keV.
These collimator cubes may obtained via anonymous FTP at heasarc.gsfc.nasa.gov in
/caldb/data/xte/pca/bcf/collresp/96jun05.
- pcabackest:
The latest version of this tool, which constructs a FITS file from which model PCA background spectra and light curves may be extracted, now does the following:
- Supports interpolation of binned models to improve background estimation.
- Accommodates individual PCU's being turned off.
- Offers the option of calculating error estimates (runs faster if omitted).
- Executes on DEC Alpha systems.
- Allows separate estimation of internal and diffuse X-ray background.
- Can search calibration database (caldb) for background models.
- runpcabackest:
This new Perl script serves as a wrapper for running multiple input files into pcabackest. The names of the output files are collected into a list which may be optionally be run through saextrct.
- PCA Background Model Files:
These files are used as input to pcabackest and runpcabackest. There is one file for each of the PCA high voltage settings. These files are currently available via FTP from legacy in the directory
/xte/calib_data and have names like
pca_bkgd_q6_e0v01.mdl where n corresponds to the time of the particular PCA high voltage settings:
The models were constructed from earth-occulted data from
non-SAA orbits with low electron contamination. These conditions are expressed in the following equations:
This model will only produce an adequate model of the internal background for non-SAA orbits. In practice, the requirement of low electron contamination is not significant since electrons are well excluded from the X-ray rates.
