Transcript Prezentacja programu PowerPoint

D. E. McKenzie
(Montana State University),
S. Gburek
(Space Research Centre, Polish Academy of Sciences),
L. W. Acton, P. C. Martens
(Montana State University)
The Point Spread Function of the
Yohkoh Soft X-ray Telescope
Poster preparation for AAS meeting
Abstract
The point spread function (PSF) of the Yohkoh solar observatory's Soft
X-ray Telescope has two primary components, a sharply defined core and a
diffuse wing due to photon scattering. Because the extent of the PSF is
significantly wider than a single pixel, its characterization is useful
for improvement of the quality of the SXT images. We will present results
from analyses of the two PSF components, and demonstrate our best model of
the core and scattering wing of the SXT point spread function. An example
of PSF deconvolution to remove the effects of photon scattering will be
given
Core part of the SXT PSF
Properties:
Size – about 5 pixels from the peak
FWHM – approx. 1.5 pixels
Depends on wavelength, position on the CCD
Calibration series to consider
BX42_APR25
Step 1,500
49
C K (0.28 keV/44.7 A) Best_Defoc
XY Scan -> X,-11,500 to -2,500; Y, -6,500 to 2,500;
BX02_APR23
Step 1,500
49
Al K (1.49 keV/8.34 A) Best_Defoc
XY Scan -> X,-11,500 to -2,500; Y, -6,500 to 2,500
BX51_APR25
Step 1,500
49
Ag L (3.00 keV/4.16 A) Best_Defoc
49
CK
XY Scan -> X,-11,500 to -2,500; Y, -6,500 to 2,500;
Could be also
BX21_APR24
Best_Defoc
XY Scan -> X,-11,500 to -2,500; Y, -6,500 to 2,500; Step 1,500
bx42_apr25 calibration series
bx02_apr23 calibration series
The image above shows 49 images of bx01_apr23 ground calibration series. Enlarged contour
plots of their peak portions in the image bellow.
bx51_apr25 calibration series
Elipticity of the core
calibration series
bx42_apr25
bx02_apr23
bx51_apr25
The PSF core gets elliptically deformed with the distance from the
CCD center. In the CCD corners can be even double peaked.
averaged core cross sections
calibration series
bx42_apr25
bx02_apr23
bx51_apr25
Solid line peak x-cross sections (upper row) and y-cross sections (the bottom row) for average PSF core for WSMR calibration
series. The average PSF shape was determined from images 7-49 for each of (mentioned above) series respectively. Error bars show
absolute errors for the selected images
Comparison of cross sections of averaged PSF core for
different energies
Ag-L
C-K
Al-K
Ag-L
C-K
Al-K
x-cross sections
y-cross sections
Core aplications
Aplications:
Deconvolution of the SXT
Flare images, mainly in
horizontal belt shown to the
left where eliptical
deformation of the core PSF
part is small.
Above, a coverage map of the CCD detector surface by full resolution SXT frames.
Gray intensity says how many times a given pixel was captured within a full resolution
frame during year 2000.
Example of deconvolution of SXT Flare images
SXT flare frame
8-MAY-00 at 10:50:21
SXT flare frame (Log10 scale)
Deconvolved image
Deconvolved image (Log10 scale)
PSF approximation from
steepest descent method
Calibration beam seen
in Al.-K line
Deconvolved PSF
PSF cross sections (x-cross section in the left panel, to the right y-cross section.
Thin solid line – cross sections of the PSF found by steepest descents method
Thick solid line – cross sections of the calibration beam
Diamonds – deconvolved PSF cross-sections