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By the PSU High Energy Astrophysics Group
Joint AXAF high-resolution mirror assembly and
AXAF CCD Imaging Spectrometer calibration
at the MSFC X-ray calibration facility
J. Nousek, L. Townsley, G. Chartas, D. Burrows,
E. Moskalenko,
R. Sambruna, J. Pesce, C. Grant, K. Nishikida,
L. Cawley, P. Broos, T.S. Koch,
A. Garmire, G. Garmire, M. Bautz, S. Jones, B.
LaMarr, and G. Ricker
Department of Astronomy & Astrophysics, The
Pennsylvania State University,
525 Davey Lab., University Park, PA 16802, U.S.A.
Center for Space Research, MIT, 77 Mass. Av.,
Cambridge, MA 02139
Abstract:
The flight AXAF CCD Imaging Spectrometer (ACIS) and
the High-Resolution Mirror Assembly (HRMA) telescope were extensively calibrated
at NASA MSFC's X-Ray Calibration Facility (XRCF). We present results based
on HRMA/ACIS characteristics that were obtained with the following tests:
(a) Point-Spread-Function (PSF) tests measuring the core and wings of
the PSF on-axis and at several off-axis positions, at the point of ideal
focus.
(b) Effective-Area (EA) tests measuring the total effective collecting
area over the PSF at many energies. We investigate the dependence of the
effective area and energy response of ACIS/HRMA as a function of several
ACIS parameters.
(c) Count-rate-linearity (pile-up) tests measuring the effect of increasing
the mean incident rate of photons per pixel on the PSF, the EA, source
centroid, and photon detection.
The goal of the calibration is to provide accurate estimates of the
in-orbit performance of the ACIS/HRMA instrument and to enable translation
of in-orbit measurements to absolute values of the incident x-ray flux
and physical models of the source emission.
AXAF, ACIS, CCD, charge-coupled device, x-ray, calibration, HRMA
Next: INTRODUCTION
Up: Publications
By the PSU High Energy Astrophysics Group
John Nousek
July 1998