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EDS Configurations: Standard-2



Packaging of science data

The Standard-2 configuration is a type of binned mode which is run for all observations. Files containing Standard-2 data are in science array format. The science data occupy the first, XTE_SA extension and comprise thirty columns of pulse-height histograms (i.e. energy spectra), one for each anode of each PCU, accumulated every 16 seconds (2 seconds if the source is bright). The pulse-height histograms have 129 channels and are accumulated from "good" xenon events (i.e. those which survive background rejection). The columns containing the pulse-height histograms are preceded by the Time column which gives the time of the start of each 16-second accumulation. To see the column names, run the ftool flcol on a sample data file.


Time and energy resolution

The time resolution is 16 seconds (2 seconds if the source is bright). The actual value is stored in the DELTAT header keyword which you can view with the ftools fdump or fkeyprint.

The spectra have 129 channels, binned according to the following scheme: channels 1-4 (combined); channels 5-53 (unbinned); channels 54-135 (binned by a factor of 2); channels 136-237 (binned by a factor of 3); channels 238-249 (binned by a factor of 4); channels 250-255 (combined).


Reduction requirements and options

Spectra and light curves may be extracted from Standard-2 data using the ftool saextrct. Apart from adjusting screening criteria, your primary reduction options include:

  • Selecting and/or combining data from the six anodes in each PCU
  • Selecting and/or combining data from the five PCU
  • Increasing the size of time bins when extracting a light curve
  • Selecting a channel range when extracting a light curve
  • Extracting 129-channel spectra

For complete details on using Standard-2 data, see the RXTE Cookbook recipe Reduction and Analysis of PCA Spectra.


Gain and offset

Gain and offset corrections are not applied by the EDS to Standard-2 data.


Other features

In addition to the xenon pulse height histograms, Standard-2 files also contain two other sets of data, namely:

  1. Five columns of 33-channel pulse-height histograms from the propane veto layer, one for each PCU, accumulated every 16 seconds (shorter if the source is bright)

  2. Background data comprising 29 columns of single-value count rates from various anodes, discriminators and veto flags. Details can be found in the Technical Appendix.

And in common with other configurations in science array format, Standard 2 files have two additional columns called Spillage and ModeSpecific, as well as a coda of keywords summarizing EDS status.


Return, if you like, to the PCA Issues chapter or to the Table of Contents.

The ABC of XTE is written and maintained by the RXTE GOF. Please email xtehelp@athena.gsfc.nasa.gov if you have any questions or comments. This particular page was last modified on Tuesday, 14-Sep-1999 13:45:45 EDT.