Chandra Calibration Status

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Chandra Calibration Status

• ACIS
• Gain correction files for epochs 30, 31 and 32
  were released in CALDB 3.4.1 (Sept 2007), 3.4.2
  (Dec. 2007) and 3.4.3 (March 2008).
• The blank sky background data sets were
  reprocessed with the latest cti-corrected
  calibration products and released in CALDB 3.4.1
• Updated gain correction files for data taken at a
  focal plane temperature of T-110 C with the BI
  chips (S1 and S3) were released in CALDB 3.4.3

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HRC

• An updated HRC-I de-gap corrections table derived
  from the AO8 Capella raster scan was released in
  CALDB 3.4.1. This improves image reconstruction
  for off-axis sources.

Web Pages
1. A tag index of all presentations given at the
Chandra calibration workshops is now on-line at
cxc.harvard.edu/ccw/tags
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ACIS and HETG Calibration Projects
Develop a set of cti-corrected calibration
products
for CC-mode observations.
ACIS Flight Grades
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Comparison of TE and CC mode grade distributions
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Comparison between ECS data taken in TE and CC
mode
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Comparison between Mn-K line profile in TE and CC
mode
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Future work on CC mode calibration
1. The CC mode cti-correcter only works when all
flight grades other than 255 are telemetered.
This will require a new default SI mode for ACIS
data taken in CC mode. 2. At present, CC mode
observations do not telemeter grade 7 events, so
a separate QE for CC mode must be developed for
all CC mode data taken until a new SI mode is
implemented.
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Plot from the IACHEC Meeting comparing MOS, PN,
and ACIS spectral fitting results in the 2-7 keV
band for a sample of 7 clusters.
HRMA Calibration Projects
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Comparison of ACIS derived temperatures in a
broad band, a hard band and from the H-like to
He-like Fe K alpha line ratio.
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Residuals in the Abell 2029 spectrum assuming the
gas temperature is given by the Fe line ratio
(kT7.9 keV).
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Two corrections have been applied to the
predictions of the raytrace code since XRCF.
Empirical XRCF correction
HRMA overlayer of 22A
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Sensitivity of derived cluster temperatures on
the depth of the HRMA overlayer without the
empirical XRCF correction.
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Spectra fitting results with a HRMA effective
area model without the XRCF empirical correction
and a depth of 20A for the overlayer.
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Spectra fitting results with a HRMA effective
area model without the XRCF empirical correction
and a depth of 20A for the overlayer.
Comparison with XMM-Newton
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Fit to the continuum source at XRCF with a
variable depth for the overlayer on each shell
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Things to do

• Determine the depth of the overlayer required to
  match the SSD continuum measurement for each
  shell.
• Apply the XRCF derived overlayer depths for each
  shell to the in-flight HRMA effective area model.
• Adjust the HETG gratings transmission efficiency
  and the HRC-S QE accordingly.
• Validate the in-flight HRMA effective area model
  with gratings and cluster data.

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HRC-I and LETG Calibration Projects

• Generate high spatial resolution, time-dependent
  gain corrections for the HRC-S

Median PHA (sum of all
pre-amps) vs. energy on HRC-I
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Median PHA at C-Ka vs.
position on central HRC-S chip
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Median SAMP (sum of 6 pre-amps) at C-Ka vs.
position on central
HRC-S chip
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Time dependence of HRC-S gain