A new method of observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar Spectroscopic Imager

Hannah, I.G. , Hurford, G.J., Hudson, H.S. and Lin, R.P. (2007) A new method of observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar Spectroscopic Imager. Review of Scientific Instruments, 78(2), 024501. (doi:10.1063/1.2437120)

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Abstract

We present a new method, fan-beam modulation, for observing weak extended x-ray sources with the Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI). This space-based solar x-ray and γ-ray telescope has much greater sensitivity than previous experiments in the 3-25 keV range, but is normally not well suited to detecting extended sources since their signal is not modulated by RHESSI's rotating grids. When the spacecraft is offpointed from the target source, however, the fan-beam modulation time-modulates the transmission by shadowing resulting from exploiting the finite thickness of the grids. In this article we detail how the technique is implemented and verify its consistency with sources with clear known signals that have occurred during RHESSI offpointing: microflares and the Crab Nebula. In both cases the results are consistent with previous and complementary measurements. Preliminary work indicates that this new technique allows RHESSI to observe the integrated hard x-ray spectrum of weak extended sources on the quiet Sun.

Item Type:Articles
Keywords:Observation and data reduction techniques; computer modeling and simulation, X- and gamma-ray telescopes and instrumentation, Solar instruments, Flares, X-ray sources; X-ray bursts, X- and gamma-ray instruments
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Hannah, Dr Iain and Hudson, Dr Hugh
Authors: Hannah, I.G., Hurford, G.J., Hudson, H.S., and Lin, R.P.
Subjects:Q Science > QB Astronomy
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Review of Scientific Instruments
ISSN:0034-6748
Published Online:07 February 2007

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