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 Normal Standard Model  Fast telescope  New coatings  CCD Window Ghost  Ghost simulator Catania,28-2,01-03 Matteo Munari – INAF OACt.

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Presentation on theme: " Normal Standard Model  Fast telescope  New coatings  CCD Window Ghost  Ghost simulator Catania,28-2,01-03 Matteo Munari – INAF OACt."— Presentation transcript:

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2  Normal Standard Model  Fast telescope  New coatings  CCD Window Ghost  Ghost simulator Catania,28-2,01-03 Matteo Munari – INAF OACt

3  It is the model of reference  Based on a slightly old design (some radii of curvature)  Structure is semiconceptual (tube & diaphgrams) 90% absorbing, 10% lambertian scattering  All lenses and window (front face included) have 1% AR coating  20A microroughness and CL500 dust on window  The CCD has a 1-QE reflectivity  Feeded by a 240mm diam circular collimated source of 4W (1W on the entrance pupil), moved along the diagonal of FoV  Wavelength weighted to reproduce energy of a G0  It has 2.5(in FoV)+1.7 (out FoV) ph/s/pxl Catania,28-2,01-03Matteo Munari – INAF OACt

4 Catania,28-2,01-03Matteo Munari – INAF OACt Reflective 99% Or Absorbing QE absorbing Two simulations: One with reflecting parts, one with absorbing Results for these models are multiplied by two (the recording surface is half) In FoV less then double, out of FoV same  ph/s NB:about the CCD Front window ghost: no difference

5 Catania,28-2,01-03Matteo Munari – INAF OACt From December Meeting / Telecon: Coatings from Galileo AR: <1.2 % in [500,1000nm](<=0.5% in [550,1000]) Has to be verified for substrates IR :7-30% has to be optimized IRx2: a 2 times ‘better’ ‘fake’ (reflectivity is the half)

6 Catania,28-2,01-03Matteo Munari – INAF OACt The Main difference is due to the ccd window ghost. ‘Only AR’ performs better the standard Not taking in account the CWG we are in specs even with the IR coating (given the AR)

7  It decreases linearly from the maximum near the center of the FPA to a radial distance of ~6°  Its intensity depends on the coatings of the surfaces  Mag diffs: 4.3, 4.9, 7.5  Same dimension of the spot Catania,28-2,01-03Matteo Munari – INAF OACt

8  Using Allen1973 we count how many stars per mag are present in 6 ‘1°-width’ annula around the center of the FoV  The center annulus has the minimum mag difference Catania,28-2,01-03Matteo Munari – INAF OACt Up to MagIRIRx2AR E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E+05  Going far from the center the mag difference grows  For every annulus we calculate how many ghosts per mag are present  We sum everything up (summing all annula to a given mag) 

9  Goal: build a way to simulate ghosts froma a real field, to have a clearer idea of the space distribution of ghosts  Realized through zemax and idl:  Generated 105 zemax files that represent all the possible double reflection ghosts, ‘doubling’ the system and substituting the ghosting surfaces with mirrors  From that files recorded the positions and the maximum radius of the spots (that are the ghosts of the ‘real’ system) for several positions along a semi-diagonal of the FoV  Given a position of a source in the field, interpolating previously recorded data, and using the data about the coatings, the ghosts disposition on the ccd can be reconstructed… Catania,28-2,01-03Matteo Munari – INAF OACt

10 Catania,28-2,01-03Matteo Munari – INAF OACt

11 Catania,28-2,01-03Matteo Munari – INAF OACt Zemax NS IDL

12 Fiji Islands, 30 Feb 2008Matteo Munari – INAF OACt 902x902 pixel  each pixel is 100 TOU pixels Source G0 mv=0 emits ~5E8 photons for our pupil in [500,1000]nm per sec In the image (calculated with photons) TOTAL=5.042E8photons per sec MAX= 5.013E8photons per sec  difference ~3E6 photons per sec Per TOU pixel is 3E6/(9e3)^2=0.036 ph/px/s Assuming Allen stellar model, the flux obtained summing up all the stars in a 30x30°is ~12 mv=0 stars  0.5 ph/px/s, compatible with previous NS simulations

13  Use a real PLATO field to feed the simulation  We need the filed data (positions, mags, spectral type)  We need the photons numbers for the spectral types Catania,28-2,01-03Matteo Munari – INAF OACt

14 Fiji Islands, 30 Feb 2008Mago Merlino - INAF OACamelot

15  Irradiance is energy/space  So in Zemax is dependant on the dimension of the detector pixel: the local irradiance is calculated by the energy falling in a pixel / the dimension of the pixel  If the pixel is bigger then the structure, the irradiance will be smaller  (288/18)^2=256=10^2.4 Catania,28-2,01-03Matteo Munari – INAF OACt Delta:10E4.5 Min: 10E-2 Delta:10E4.5 Min: 10E-2 Delta:10E7 Min: 10E-2 Delta:10E7 Min: 10E-2 Zemax pixel: 18 micron Zemax pixel: 288 micron


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