2. SXT Soft X-Ray Telescope Onboard the Yohkoh Satellite http://solar.physics.montana.edu/winter/RSS_Presentation/ SXT.ppt

3. Overview Brief Description The Trouble with X-Rays Optical Design System Parameters Block Diagram Effective Areas Why I Don’t Have a SNR Calculation NOBODY HAS A SNR CALCULATION !!! Sample data References

4. Soft X-Ray Telescope (SXT) was designed to study “thermal” X-ray emissions from solar coronal sources (1/2 MK-30 MK) 0.25 – 4 keV range (3-45 Å) E[keV]=12.40[keV* Å]/ [Å] Passive sensor One of many instruments onboard Yohkoh Satellite Launched from Kagoshima, Japan on August 31, 1991 Trae Winter arrives in Bozeman on January 6, 2002 to take over MSU SXT science planning January 9, 2002 announced (to me at least) that Yohkoh was lost on December 14, 2001. Brief Description I

5. Brief Description II: SXT http://isass1.solar.isas.ac.jp/yohkoh/images/teemsxt.gif

6. Brief Description III: Yohkoh (Solar-A) Ogawara, Y.Ogawara, Y., et al. 1991

7. Atmospheric transmission of X-Ray and E.U.V. is essentially 0 Sounding Rockets Satellites X-Rays ignore “most” refractive optics The index of refraction, n[ ], is ~1 at X-ray wavelengths for all material X-Rays are not easily reflected More likely to be transmitted or absorbed The Trouble with X-Rays I

8. X-Rays can be made to reflect off of high density materials at shallow angles Analogous to total internal reflection  critical is the angle in arcminutes,  is the mass density in g cm -3, E is the photon energy in keV http://harris.roe.ac.uk/~jcm/thesis/thesis.html The Trouble with X-Rays II

9. Optical Design I: Wolter I Telescope http://www.sr.bham.ac.uk/xmm/images/mirrors/lightanim.gif

10. Optical Design II: “Ray-Trace” of SXT (Mod. Wolter I) http://www.lmsal.com/SXT/

11. Optical Design III: Breakaway http://www.lmsal.com/SXT/

12. System Parameters CCD  Cooled to ~-18°C  Array Size: 1024 X 1024 Pixel Size: 18.281  0.002  m 2.4528  0.0005”  1779 km Time Resolution: 0.5 sec. (Special) 2.0 sec. (normal) Telescope Geometrical Area 261.75 mm 2 Effective Area (Peak) 78 mm 2 @ 8 Å Effective Focal Length 1535.6 mm Construction Zerodur™ Glass/Ceramic 420 Å Au on 80 Å Cr Surface Roughness 3.8 Å r.m.s.

13. Block Diagram Mirror Filter CCD Shutter Data Processor Memory 10 MB Goldstone Canberra Madrid Kagoshima

14. Effective Area I

15. Effective Area II: Now with filters a) No filter b) 1265 Å Al c) Dag d) 2.52  m Mg e) 11.6  m Al f) 119  m Be

16. SNR Calculation I X  Energy Per [Å] CCD Response (e - /keV) Sum the electons/sDN=(#E/100)+(13,30, 69) For noise repeat but the photon spectrum is now the square root of itself.

17. SNR Calculation I Assumptions  Solar active region  Electron Density 1 x 10 9 particles cm -3  A certain set of elemental abundances  Ionization equilibrium approximations SNR = 1.73 or 2.4 dB Signal=22.5 DN s -1 pixel -1, Noise= 13 DN s -1 pixel -1 Why don’t I still have a true SNR??

18. Sample Data

19. http://www.lmsal.com/ypop/sxt_movie.html

20. References Ogawara, Y.Ogawara, Y., et al. 1991, “The Solar-A Mission - an Overview”, SOLAR PHYSICS, 136, pp. 1-16 Tsuneta, S.Tsuneta, S., et al. 1991, “The Soft X-ray Telescope for the SOLAR-A Mission”, Solar Physics, 136, pp. 37-67 Web Resources: Yohkoh Data Analysis Guide and Instrument Guide Available at http://umbra.gsfc.nasa.gov/yohkoh_archive.html#YAG ISAS Yohkoh Web Page http://isass1.solar.isas.ac.jp/yohkoh/images/ James Manners’ Thesis Page http://harris.roe.ac.uk/~jcm/thesis/thesis.html Lockheed Martin Solar & Astrophysical Lab Yohkoh Web Page http://www.lmsal.com/SXT/ Marshall Space Flight Center http://science.nasa.gov/ssl/pad/solar/ Yohkoh Public Outreach Project http://solar.physics.montana.edu/YPOP/

21. Slides that I deleted due to lack of time

22. Scientific Context: Begin the Space Age “Almost” no E.U.V. or X-Ray photons @ surface No reason to expect solar X-Rays Sounding rockets detected X-Rays Then came OSO, Skylab RESOLUTION!!! http://science.nasa.gov/ssl/pad/solar/images /s054_1.gif http://science.nasa.gov/ssl/pad/solar/images /skylab2.jpg

23. Temperature Response Based on synthetic spectra with certain input parameters (elemental abundances, electron density, emission measure (amount of emitting plasma))