mi018.labonte02 Posted: 12-Oct-96 Updated: 16-Dec-96 Events specified: Post flare loops of the 25-JUN-92 20 UT X class flare
Collaboration: Barry LaBonte (University of Hawaii) Kevin Reardon (Naples Observatory)
Science: The dynamic range of the solar soft x-ray flux
makes the determination of temperature
difficult. We propose to explore a
"new" method that works equally well
independent of flux level.
Method: We will determine if the photon shot noise
can be used to provide a measure of the
mean energy per photon, which is
a monotonic function of temperature.
Required data: 1992 June 25 22:50 - 23:10 UT
There are about 10 minutes of SXT images
during the decay phase of a large flare
that serve our needs.
Update 16-Dec-96
We have finished a paper titled:
X-ray Photon Spectroscopy with the YOHKOH Soft X-ray Telescope
by Barry LaBonte (University of Hawaii) Kevin Reardon (Astronomical Observatory of Capodimonte)
Abstract. Individual X-ray photons in the keV energy range produce hundreds of photoelectrons in a CCD array detector. The Yohkoh Soft X-ray Telescope uses a CCD in an integrating mode and makes temperature estimates from multiband filter photometry. We show that the variance of repeated SXT images of a source through a single filter can be used to measure the mean energy per photon, which is proportional to temperature. Given the large dynamic range of the soft X-ray flux observed from the Sun, future instruments should take advantage of photon spectroscopy.
We will be submitting to Solar Physics.
The full text (90 KB postscript file) and figures are available at
http://www.solar.ifa.hawaii.edu/~labonte/blabonte.html
under "SXT photon variance" if you want a full copy.