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An EUV Imaging Detector of Space Solar Telescope Qian Song, Binxun Ye, Zhaowang Zhao National Astronomical Observatories, China Chinese Academy of Sciences SWD 2005, Taormina, Jun,19-26 Introduction of SST The Space Solar Telescope, the first space astronomy program in China SWD 2005, Taormina, Jun,19-26 Satellite Solar synchronous circular orbit Orbit height: 735 km Inclination: 98.3° Period: 99.3 min Attitude: accuracy ±6", stability ±3"/s Weight: 2 ton Lifetime: 3 years Launch: LM-4B SWD 2005, Taormina, Jun,19-26 Payloads • • • • • SWD 2005, Taormina, Jun,19-26 MOT EUT HWT WBS SIR Main optical telescop, MOT with a 2-D polarizing spectrograph, working in 8 channels simultaneously Resolution 0.1‘ FOV 2.8'×1.5‘ Polarization Accu. 2×10 –4 SWD 2005, Taormina, Jun,19-26 Payloads •HWT: a Hα and white light telescope, whole sun viewing resolution 1 , FOV 0.7°×0.7° • WBS: a wide band spectrometer, investigating high energy flare process on -ray, hard & soft x-ray • SIR: solar and interplanetary radiospectrometer, 1-60GHz nonthermal electron populations SWD 2005, Taormina, Jun,19-26 EUT Based on the EUVSAT proposal. Consists of four normal incidence telescopes mounted in a vacuum vessel, which should overlap, be well aligned and synchronized with each other and with the images of the MOT. Field of view 7’×7’ Resolution 0.8” Wave length 12.8, 17.1, 19.5, 30.4 nm (subject to change) Focal length 7.04 m Distance between Mirrors 1.4 m Primary Mirror 120 mm Secondary mirror 48 mm SWD 2005, Taormina, Jun,19-26 EUT structure SWD 2005, Taormina, Jun,19-26 EUT Detector: requirements To achieve highest sensitivity, a combination of a phosphor screen, an image intensifier and a CCD is proposed. This not only improves the sensitivity for low intensity scenes, but as a bonus it provides an electronic shutter as well, one with no moving part. 2048×2048 format At least 12 bit dynamic range between CCD readout noise and full well capacity Spacial resolution should match the telescope’s, 0.8”, or 27.3μ, 36.6 lp/mm SWD 2005, Taormina, Jun,19-26 EUT Detector: Structure In order to achieve high sensitivity, an image intensifier is used A phosphor screen is needed to converse EUV photons to visible. A CCD imager is to be used with format changing optics (fiber optic taper) SWD 2005, Taormina, Jun,19-26 Phosphor’s response on EUV 4.00E-009 3.50E-009 3.00E-009 Current (A) 2.50E-009 2.00E-009 1.50E-009 1.00E-009 5.00E-010 0.00E+000 50 100 150 200 Wavelength (Angstrom) SWD 2005, Taormina, Jun,19-26 250 300 Phosphor’s output against input 270 170 17.1nm l9.5nm 260 160 150 240 230 140 220 130 210 200 120 190 110 180 170 100 60 70 80 90 100 Current of Accumulate Circle (mA) SWD 2005, Taormina, Jun,19-26 110 19.5nm's Current (pA) 17.1nm's Current (pA) 250 MCP image intensifier, resolution 57 Lp/mm, gain 8900 cd /m2 /Lx, equivalent background irradiance 0.16 µLx Optic taper: resolution >102Lp/mm SWD 2005, Taormina, Jun,19-26 The front end of the detector SWD 2005, Taormina, Jun,19-26 The outlook and inside of the detector 荧光屏 像增强器 光锥 CCD SWD 2005, Taormina, Jun,19-26 5s dark: MCP contribution 800DN SWD 2005, Taormina, Jun,19-26 Test on BSRF SWD 2005, Taormina, Jun,19-26 The image of the 17.1nm beam of BSRF SWD 2005, Taormina, Jun,19-26 Resolution test on 17.1nm 9µ 13µ 23µ 19µ SWD 2005, Taormina, Jun,19-26 The intensity distribution of the 19μ grid 17500 19 miron grid CCD Readout (DN) 17000 16500 16000 15500 15000 14500 1140 1144 1148 1152 1156 1160 1164 Pixel No. SWD 2005, Taormina, Jun,19-26 1168 1172 1176 1180 Response of the detector on 17.1nm & 19.5nm 2.00E+010 1.80E+010 G: measurements on 17.1nm Linear Fit of DATA171_G 1.80E+010 H: measurements on 195nm Linear Fit of DATA195_H 1.60E+010 - - 1.60E+010 R: 21 e /photon R: 18 e /photon Readout electrons Readout electrons 1.40E+010 1.40E+010 1.20E+010 1.00E+010 8.00E+009 1.20E+010 1.00E+010 8.00E+009 6.00E+009 6.00E+009 4.00E+009 4.00E+009 3 4 5 6 7 8 9 10 11 12 3 5 6 7 8 Incident photon number (10 photons) Incident photon number (10 photons) 17.1nm, 18e/photon 4 8 8 19.5nm, 21e/photon SWD 2005, Taormina, Jun,19-26 9 10 Possible Solution Better phosphor screen, MCP, fiber optic taper Open MCP with CrI or KBr-coated photon cathode+CCD EUV L3 CCD Suggestions and comments are very precious for us SWD 2005, Taormina, Jun,19-26 SWD 2005, Taormina, Jun,19-26