A solar flare X-ray polarimeter for the space shuttle

✍ Scribed by J. R. Lemen; G. A. Chanan; J. P. Hughes; M. R. Laser; R. Novick; I. T. Rochwarger; M. Sackson; L. J. Tramiel

• Publisher: Springer
• Year: 1982
• Tongue: English
• Weight: 865 KB
• Volume: 80
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00147980

✦ Synopsis

We have recently built and tested an instrument designed to measure the polarization of the hard (5-30 keV) X-ray emission from solar flares, and thereby to investigate the energy release mechanism and constrain flare models. In particular, these measurements will help to determine whether hard X-ray bursts are produced by nonthermal or by thermal electrons. The polarimeter makes use of the angular dependence of Thomson scattering from targets of metallic lithium. It has an energy resolution of a few keV, a time resolution of 5 s, and suff• sensitivity to measure polarization levels (3 a) of a few percent in about 10 s for a moderate strength solar flare. The instrumental polarization has been directly measured and found to be within the design goal of ~ 1%. This polarimeter is scheduled to be flown as part of the OSS-I pallet on an early Space Shuttle mission.

* Haug (1979Haug ( , 1981) ) has also considered the possibility of polarization measurements of X-ray lines from hydrogenic ions during solar flares. However, the small polarization expected in these cases make such measurements considerably more difficult than those considered here.