Chandra LETG higher-order diffraction efficiencies

Bradford J. Wargelin; Peter W. Ratzlaff; Deron O. Pease; Vinay L. Kashyap; Jeremy J. Drake

doi:10.1117/12.509361

3 February 2004 Chandra LETG higher-order diffraction efficiencies

Bradford J. Wargelin, Peter W. Ratzlaff, Deron O. Pease, Vinay L. Kashyap, Jeremy J. Drake

Proceedings Volume 5165, X-Ray and Gamma-Ray Instrumentation for Astronomy XIII; (2004) https://doi.org/10.1117/12.509361
Event: Optical Science and Technology, SPIE's 48th Annual Meeting, 2003, San Diego, California, United States

Abstract

Accurate calibration of the Chandra Low Energy Transmission Grating (LETG) higher-order (|m|>1) diffraction efficiencies is vital for proper analysis of spectra obtained with the LETG's primary detector, the HRC-S, which lacks the energy resolution to distinguish different orders. Pre-flight ground calibration of the LETG was necessarily limited to sampling a relatively small subset of spectral orders and wavelengths, and virtually no higher-order data are available in the critical region between 6 and 10 Å. In this paper, we describe an analysis of diffraction efficiencies based on in-flight data obtained using the LETG's secondary detector, the ACIS-S. Using ACIS, the relative efficiency of each order can be studied out to |mλ| ~ 80 Å, which is nearly one-half of the LETG/HRC-S wavelength coverage. We find that the current models match our results well but can be improved, particularly for the even orders just longward of the Au-M edge at 6 Å.

Citation Download Citation

Bradford J. Wargelin, Peter W. Ratzlaff, Deron O. Pease, Vinay L. Kashyap, and Jeremy J. Drake "Chandra LETG higher-order diffraction efficiencies", Proc. SPIE 5165, X-Ray and Gamma-Ray Instrumentation for Astronomy XIII, (3 February 2004); https://doi.org/10.1117/12.509361

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