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WFC3 SOC, October 04, 2007
WFC3 GrismsResults from TV2
2D Simulations
Harald Kuntschner, Jeremy Walsh, Martin Kümmel
ST-ECF
WFC3 SOC, October 04, 2007
WFC3-IR G102
directimage
0th order 1st order 2nd order
1014 pixel (full size)
detector defectsCombined white light + direct image
WFC3 SOC, October 04, 2007
WFC3-IR G141
directimage
0th order 1st order 2nd order
1014 pixel (full size)
detector defects
3rd order
Combined white light + direct image
WFC3 SOC, October 04, 2007
WFC3-UV G280
Direct image
0th order
1st order -1st order
4096 pixel (full size)
Combined white light + direct image
WFC3 SOC, October 04, 2007
WFC3-UV G280
0th order
+1st -1st
4096 pixel (full size)
+2st -2st
Combined monochromatorsteps
WFC3 SOC, October 04, 2007
WFC3-UV G280
+1+2
• +8 to -8 orders visible
• Heavy order overlap for > +2 order
• Order overlap in y-direction between +1st and +2nd beyond ~380nm
+3+4
+5
+8
+7+6
0-1
-2-3
-4
-5-6
-7
-8
WFC3 SOC, October 04, 2007
WFC3-IR G102 Throughput
• 1st order– Peak efficiency of ~30%
at 960 - 1120nm– Good sensitivity range:
840 - 1140nm
• 2nd order– Efficiency < 5%
• 0th order– Efficiency < 1.5%
WFC3 SOC, October 04, 2007
WFC3-IR G102 aperture corrections
• Aperture corrections are largely wavelength independent
• 95% flux within ~10 pixel aperture
WFC3 SOC, October 04, 2007
WFC3-IR G141 Throughput
• 1st order– Peak efficiency of ~40%
at 1420 - 1640nm– Good sensitivity range:
1120 - 1660nm
• 2nd order– Efficiency < 6%
• 0th order– Efficiency < 1.5%
WFC3 SOC, October 04, 2007
WFC3-IR G141 aperture corrections
• Aperture corrections are largely wavelength independent
• 95% flux within ~12 pixel aperture
WFC3 SOC, October 04, 2007
WFC3-UV G280 Throughput
• 1st order– Peak efficiency of 24%
at 240nm– Good sensitivity range:
200 - 330nm
• 2nd order– Efficiency < 2%
• 0th order– Efficiency equal to first
order at 330nm and rising!
WFC3 SOC, October 04, 2007
WFC3-UV G280 Throughput
• Higher order efficiencies are at the ~0.1% level
WFC3 SOC, October 04, 2007
WFC3-IR G141 trace
• Linear trace solutions with rms < 0.05 pixel
• f(X-Xref) = 0.0074 * (X-Xref) + 1.1
WFC3 SOC, October 04, 2007
WFC3-IR G1412-dim trace solution
central trace:
f(X-Xref) = 0.0074 * (X-Xref) + 1.1
Offset = f(X,Y)
rms < 0.2 pixel
Slope = f(X,Y)
WFC3 SOC, October 04, 2007
WFC3-IR G141 dispersion
• Linear dispersion solutions with rms < 1 Å
• f(X) [Å] = 46.9 * (X) + 8950
* Data points omitted in fit due to wavelength shift caused by steep sensitivity decline
WFC3 SOC, October 04, 2007
WFC3-IR G1412-dim dispersion solution
central dispersion solution:
f(X’) [Å] = 46.9 * (X’) + 8950
Offset = f(X,Y) units=Å
rms < 0.1 pixel
Dispersion = f(X,Y) units=Å
WFC3 SOC, October 04, 2007
WFC3-IR G1022-dim disp solution
central dispersion solution:
f(X) [Å] = 24.6 * (X) + 6376
Offset = f(X’,Y’) units=Å
rms < 0.1 pixel
Dispersion = f(X’,Y’) units=Å
WFC3 SOC, October 04, 2007
WFC3-IR PSF
Gaussian FWHM = 2.3 pixelMoffat FWHM = 1.9 pixel; beta=1.08
Gaussian FWHM = 2.7 pixelMoffat FWHM = 2.3 pixel; beta=1.14
Moffat
Gaussian
WFC3 SOC, October 04, 2007
WFC3-UV PSF
Gaussian FWHM = 3.4 pixelMoffat FWHM = 2.9 pixel; beta=1.4
Gaussian FWHM = 3.8 pixelMoffat FWHM = 3.3 pixel; beta=1.5
Moffat
Gaussian
230-260 nm 300-400 nm
WFC3 SOC, October 04, 2007
WFC3-UV G280 Trace
+2 order +1 order -1 order
5th order polynomial fits
200nm
530nm
200nm
200nm 530nm530nm