New Calibration Web Pages

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New Calibration Web Pages

We have substantially changed the organization of the Chandra calibration web pages with the intention of making information about calibration easier to find. In particular our home page (http://cxc.harvard.edu/cal/) now contains a table (Table 2) of the fundamental calibration products, with information on how well we planned to calibrate each one (the pre-launch "requirement"), how well we have actually calibrated it, and how much better we plan to do in the future (the "goal"). More detailed information on a given calibration characteristic, including links to related memos can be found by clicking on that item in the "Characteristic" column.

Characteristic Det/Grat Requirement PresentGoal
(1 sigma) (Dec 2003)  
Absolute Positions HRC/ACIS 1.0" 0.6" (90%) 0.6" (90%)
Relative Spatial PositionsACIS-I 0.1" 0.1" 0.1"
ACIS-S3 0.1" 0.1"
HRC-I 0.3" 0.1"
Absolute Energy Scale ACIS 1 eV 3.0 eV at 1.5 keV 3.0 eV
LETG/HRC-S 0.02A 0.013A 0.010A
MEG/ACIS-S 0.03A (MEG) 0.011A0.010A
HEG/ACIS-S 0.03A (MEG) 0.006A0.005A
Absolute Imaging Efficiency (Effective Area) ACIS 2% 12% 5%
HRC 7% 10% 7%
Absolute Gratings Efficiency (Effective Area)
1st order
LETG/HRC-S 10% 15% 10%
HETG/ACIS-S 10% 15%10%
Absolute Gratings Efficiency (Effective Area)
2nd - 5th Orders
LETG/HRC-S   20% 15%
HETG/ACIS-S   20%15%
Energy Resolution (FWHM) ACIS 3% 12% 8%
LETG/HRC-S 3% 20% 10%
MEG/ACIS-S 3% 4% 3%
HEG/ACIS-S 3% 5% 3%
Relative Efficiency (Effective Area) ACIS 1% on scales of 1' 2.0% 1.0%
ACIS   10% 3% on scales of 200 eV
HRC 1% on scales of 1' 0.7% 0.7%
LETG/HRC-S 3% on scales of 0.05A 6% 3%
HETG/ACIS-S 3% on scales of 0.05A 10% 3%
Point Spread Function HRC/ACIS 0.1% of peak within 1" annuli out to 16" 0.004% 0.004%
0.001% of peak between 16" and 20" 0.00008% 0.00008%
Relative Time Precision HRC 16 mu s 4-18 mu s 16 mu s
Absolute Time Accuracy HRC 100 mu s 35 mu s 35 mu s
ACIS-CC   1.5 m sec1.5 m s

Larry David for the Calibration Group




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