The Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center (GSFC) seeks a creative, innovative individual with strong teamwork and leadership skills to serve as Director of the High Energy Astrophysics Science Archive Research Center (HEASARC). This will be a permanent civil servant position. + Learn more.
acisabs: Chandra ACIS q.e. decay
This model accounts for the decay in the ACIS quantum efficiency most likely
caused by molecular contamination of the ACIS filters. The user needs to
supply the number of days between Chandra launch and observation. The acisabs
parameters related to the composition of the hydrocarbon and the rate of decay
should be frozen and not modified. The present version of acisabs
is to be used for the analysis of bare ACIS I and ACIS S data. For the
present version of acisabs one must use the standard qe file
vN0003 instead of the optional vN0004 file.
Because of the present large uncertainty in the ACIS gain at energies
below 350eV we recommend that events in the 0-350eV range be ignored in the
spectral analysis until the gain issue is resolved.
acisabs calculates the mass absorption coefficients of the
contaminant from atomic scattering factor files provided at
http://henke.lbl.gov/optical_constants/asf.html
par1 |
Days between Chandra launch and ACIS observation |
par2 |
Slope of linear quantum efficiency decay |
par3 |
Offset of linear quantum efficiency decay |
par4 |
Number of carbon atoms in hydrocarbon |
par5 |
Number of hydrogen atoms in hydrocarbon |
par6 |
Number of oxygen atoms in hydrocarbon |
par7 |
Number of nitrogen atoms in hydrocarbon |
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Last modified: Friday, 23-Aug-2024 13:20:40 EDT
The Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center (GSFC) seeks a creative, innovative individual with strong teamwork and leadership skills to serve as Director of the High Energy Astrophysics Science Archive Research Center (HEASARC). This will be a permanent civil servant position. + Learn more.
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