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Session 1 - Chromosphere, Corona, Flares.
Display session, Friday, June 27
Ballroom B, Chair: Charles Kankelborg

[1.73] Observations of Flare Thermal X-rays with the NEAR PIN Detector

R. A. Schwartz (GSFC and HSTX), J. I. Trombka (GSFC), R. Starr (GSFC and CUA)

Two C-level solar flares were observed by the Near Earth Asteroid Rendezvous (NEAR) solar monitor detectors on 8 May 1996. We use the observations made with the 0.11 cm square solid state silicon PIN detector to determine the solar X-ray flux in the 1.9-10 keV energy region with an efficiency ranging from 0.2-0.8, peaking near 6 keV. We fit to a single temperature bremsstrahlung emission spectrum by convolving the model with the detector response and comparing at 136 PHA channels, the derived temperatures ranged from 9 to 18 MegaKelvin. Some of the intervals are well-characterized by this convolved input form, yielding Chi-Square values near 1 and fitting both the continuum and the details of the broadened (580 eV FWHM) iron complex around 6.6 keV.

We have made direct comparisons with the observations made with the X-ray monitors on GOES7, GOES8, and GOES9 where we have folded the measured spectrum through the GOES response functions. The NEAR PIN detector PHA completely spans the effective response of the GOES short wavelength channel, commonly 0.5-4 Angstroms, and shows significantly more flux over this effective bandwidth. For the NEAR measurement best represented by an isothermal over the effective energy range, the NEAR derived GOES fluxes would be 30-50% larger than those reported. This discrepancy cannot be resolved by any flare differential emission measure. We also report comparisons with the Yohkoh BCS and BATSE Spectroscopy Discriminator channels.


The author(s) of this abstract have provided an email address for comments about the abstract: Richard.A.Schwartz.1@gsfc.nasa.gov

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