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Suzaku News #051: CALDB error/HXD-PIN tuned background

18 June, 2008


[1] Error in the June 2 release of CALDB
[2] Release of "tuned" background model for HXD/PIN


[1] Error in the June 2 release of CALDB

The XIS team has discovered a bug in the XIS quantum efficiency (QE)
files (ae_xi[0-3]_quanteff_20080504.fits) released in the recent CALDB
update made on June 2, 2008.

Specifically, the team has found that the latest QE files are not
correct below 2 keV, with errors as large as 20%.  RMF files generated
by xisrmfgen with the QE files are thus not correct.  Related
problems also exist in XIS "teldef" and XRT "reflect" and "mirror"
files, which affect the ARF files as well.

As of 2008 June 18, we have re-ingested the CALDB files to point to
earlier versions of these calibration files.  This corrected version
is tagged "20080616" in the CALDB, for both the XIS and the XRT; the
HXD CALDB dated 20080602, however, is still current.  The XIS0
contamination file originally released on June 2 is still valid,
and it is flagged as such in the 20080616 version.

Users who have downloaded the June 2 version of Suzaku CALDB,
or have used the Suzaku CALDB since June 2 to generate response
files, are advised to take corrective action of re-downloading
the corrected CALDB and/or re-generating the responses.

We apologize for the inconvenience.


[2] Release of "tuned" background model for HXD/PIN

The HXD team has released a new ("tuned") non X-ray background (NXB)
model for the PIN.  Since this model has significantly lower
systematic uncertainties (1.3%) compared to the previous (now called
"quick") model, users are advised to use the tuned NXB model whenever

Because this method needs one month worth of calibrated GSO event
files, it takes 1-2 months after finishing the pipeline processing
for the HXD team to deliver the tuned NXB model.  The HXD team will
therefore continue to produce the quick NXB model files as well,
which should now be used for quick-look purposes only, before the
tuned NXB model becomes available.

For more, see