The SolarB EUV Imaging Spectrometer an Overview of
The Solar-B EUV Imaging Spectrometer: an Overview of EIS J. L. Culhane Mullard Space Science Laboratory University College London 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
EIS on the Solar-B Spacecraft Roles and Responsibilities UK (MSSL (PI), Birmingham, RAL): CCD cameras, Structure, On-board Processor, Filter Housing, Calibration USA (NRL, GSFC, Columbia): Optics, Coatings, Mechanisms, Filters, Japan (NAOJ, ISAS): Testing, Integration with Spacecraft Norway (Ui. O): ` EGSE Software All participants are involved in Post-launch Mission Operations and Data Analysis 2 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
EIS - Instrument Features • Large Effective Area in two EUV bands: 170 -210 Å and 250 -290 Å – Multi-layer Mirror (15 cm dia ) and Grating; both with optimized Mo/Si Coatings – CCD camera; Two 2048 x 1024 high QE back illuminated CCDs • Spatial resolution: 1 arc sec pixels/2 arc sec resolution • Line spectroscopy with ~ 25 km/s per pixel sampling • Field of View: – Raster: 6 arc min× 8. 5 arc min; – FOV centre moveable E – W by ± 15 arc min • Wide temperature coverage: log T = 4. 7, 5. 4, 6. 0 - 7. 3 K • Simultaneous observation of up to 25 lines/spectral windows 3 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
EIS Optical Diagram Primary Mirror Entrance Filter CCD Camera Front Baffle Grating 4 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Primary Mirror Assembly • Multilayer-coated mirror shown installed in the instrument structure Raster Drive Primary Mirror 5 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Slit/Slot and Shutter Assembly Slit/Slot Wheel - before blackening Shutter 6 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Grating Assembly Grating Focus Drive 7 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Atomic Force Microscope Profile of Laminar Grating • AFM profile of grating grooves in a 1 μm x 1 μm region near grating center for grating FL-8 . • Mean groove depth is 6. 4 nm and the land width is 108 nm (4200 lines/mm) • Grating substrates fabricated by Zeiss - Holographic technique used to form a sinusoidal groove pattern - Ion beam etching used to shape laminar grooves and to achieve specified groove depth 8 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
CCD Camera and Readout Electronics CCDs with cold finger attachments Camera and associated electronics installed in the instrument structure Dual CCD Camera 9 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
EIS Instrument Pre-Calibration EIS Instrument Completed 10 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Spectroscopic Performance Long Wavelength Band • Ne III lines near 267 Å from the NRL Ne–Mg Penning discharge source • Gaussian profile fitting gives the FWHM values shown in the right-hand panel /D ~ 4600 57. 7 mÅ 58. 1 mÅ 57. 9 mÅ 11 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Spectroscopic Performance Short Wavelength Band • Mg III lines near 187 Å from the NRL Ne–Mg Penning discharge source • Gaussian profile fitting gives the FWHM values shown in the right-hand panel /D ~ 4000 47 mÅ 12 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Observables • Observation of single lines – – – • w Line intensity and profile Line shift ( ) → Doppler motion Line width ( w) and temperature → Nonthermal motion Observation of line pair ratios – – • Temperature Density Observation of multiple lines – Differential emission measure 13 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Slit and Slot Interchange • Four slit/slot selections available • EUV line spectroscopy - Slits - 1 arcsec 512 arcsec slit - best spectral resolution - 2 arcsec 512 arcsec slit - higher throughput • EUV Imaging – Slots – Overlappogram; velocity information overlapped – 40 arcsec 512 arcsec slot - imaging with little overlap – 250 arcsec 512 arcsec slot - detecting transient events 14 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
EIS Field-of-View Shift of FOV center with coarse-mirror motion Maximum FOV for raster observation 360 900 512 40 slot 250 slot Raster-scan range EIS Slit 15 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
EIS Effective Area Primary and Grating: Measured - flight model data used Filters: Measured - flight entrance and rear filters CCD QE: Measured - engineering model data used Following the instrument end-to-end calibration, analysis suggests that the above data are representative of the flight instrument 16 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Detected photons per 1 1 area of the Sun per 1 sec exposure. Ion Wavelength (A) log. T Nphotons AR M 2 -Flare Fe X 184. 54 6. 00 15 36 Fe XII 186. 85 / 186. 88 6. 11 13/21 105/130 Fe XXI 187. 89 7. 00 - 346 188. 23 / 188. 30 6. 11 41 / 15 110/47 Fe XXIV 192. 04 7. 30 - 4. 0 104 Fe XII 192. 39 6. 11 46 120 Ca XVII 192. 82 6. 70 31 1. 8 103 Fe XII 193. 52 6. 11 135 305 Fe XII 195. 12 / 195. 13 6. 11 241/16 538/133 Fe XIII 200. 02 6. 20 20 113 Fe XIII 202. 04 6. 20 35 82 Fe XIII 203. 80 / 203. 83 6. 20 7/20 38/114 Fe XI EIS Sensitivity 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. Nphotons AR M 2 -Flare Fe XVI 251. 07 6. 40 - 108 Fe XXII 253. 16 7. 11 - 71 Fe XVII 254. 87 6. 60 - 109 Fe XXVI 255. 10 7. 30 - 3. 3 103 He II 256. 32 4. 70 16 3. 6 103 Si X 258. 37 6. 11 14 62 Fe XVI 262. 98 6. 40 15 437 Fe XXIII 263. 76 7. 20 - 1. 2 103 Fe XIV 264. 78 6. 30 20 217 Fe XIV 270. 51 6. 30 17 104 Fe XIV 274. 20 6. 30 14 76 Fe XV 284. 16 6. 35 111 1. 5 103 EIS Instrument Overview 17
Doppler Velocity and Line Width Uncertainties Flare line Bright AR line Photons (1 1 area)-1 sec-1 Photons (1 1 area)-1 (10 sec)-1 Doppler velocity Number of detected photons Line width 18 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
Processed Science Data Products • Intensity Maps (Te, ne): – images of region being rastered from the zeroth moments of strongest spectral lines • Doppler Shift Maps (Bulk Velocity): – images of region being rastered from first moments of the strongest spectral lines • Line Width Maps (Non-thermal Velocity): – images of region being rastered from second moments of the strongest spectral lines 19 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
First 90 Day Observing Plan • Flare Trigger and Dynamics: Ø Spatial determination of evaporation and turbulence in a flare • Active Region Heating: Ø Spatial determination of velocity field in AR loops for a range of Te values • Quiet Sun Studies: Ø Correlate coronal Te, ne, v with the magnetic topology inferred from FPP • Coronal Holes and Hole Boundaries: Ø Measurement of intensity and velocity field at a coronal hole boundary and at selected sites in coronal holes 20 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
CONCLUSIONS • Following SOHO CDS, the EIS instrument will provide the next steps in EUV spectral imaging of the corona: – – x 10 enhancement in Aeff from use of multilayers and CCDs x 5 enhancement in spectral resolution x 2 -3 enhancement in spatial resolution Like CDS; absolute calibration performed to ± 20% • EIS will: – Address a broad range of coronal science topics – Enable major goals of Solar-B mission by relating coronal response to magnetic flux emergence and material flows 21 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
END OF TALK 22 6 th Solar B Science Meeting, Kyoto 8 th November, 2005. EIS Instrument Overview
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