1. 2001 Mars Odyssey GRS 1 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Early Mapping of Hydrogen, Potassium and Silicon from the Gamma lines L. d’Uston, S. Maurice, O. Gasnault

2. 2001 Mars Odyssey GRS 2 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping

3. 2001 Mars Odyssey GRS 3 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Gammas Raw data from Query Tool (gammaspatial + engineering) Time selection: Feb 20 – March 9 before annealing Temperature selection: GRS_IS_TEMP_A < - 165 o C  2 weeks  55,972 spectra (~304 hours) Neutrons Press release data from W. Feldman & R. Tokar Data sets

4. 2001 Mars Odyssey GRS 4 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping

5. 2001 Mars Odyssey GRS 5 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping

6. 2001 Mars Odyssey GRS 6 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Energy callibration [W. Boyton, Feb 02] Slope = 0.6152 keV/channel Intercept = 18.86 keV 2.4 MeV 2.0 MeV Continuum H-line Background 2.215 – 2.230 MeV Spectral Analysis Energy (counts/19.6 sec)

7. 2001 Mars Odyssey GRS 7 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Min = 530 spectra Mapping at 30 o resolution (equal area) (8) (12) (8) (15) (12) Application of the Mapping/Display Toolkit

8. 2001 Mars Odyssey GRS 8 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Map of background

9. 2001 Mars Odyssey GRS 9 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Above +45 o Below –45 o  Effects of atmospheric Absoption Background with MOLA

10. 2001 Mars Odyssey GRS 10 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Map of background (corrected for 0 km MOLA altitude) (same color range)

11. 2001 Mars Odyssey GRS 11 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Map above continuum  H-LINE map

12. 2001 Mars Odyssey GRS 12 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Map of H-line (corrected for 0 km MOLA altitude)

13. 2001 Mars Odyssey GRS 13 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Smooth 4 o Epithermal neutrons [Press release data] ! Arb. Units = constant - epithermals !

14. 2001 Mars Odyssey GRS 14 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Epithermal neutrons: Rebin to 30 o

15. 2001 Mars Odyssey GRS 15 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Correlation epithermals/gammas (1)

16. 2001 Mars Odyssey GRS 16 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Correlation epithermals/gammas (2)

17. 2001 Mars Odyssey GRS 17 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Map of HYDROGEN is feasible; it makes sense… Map of BACKGROUND: –Correlated with altitude (atmospheric effect) –Corrected map shows signal at poles Agreement between epithermal neutrons & gamma H-line: –Very good at first order –Strenghten epithermal detection of H –Differences have not been interpreted Conclusions Quantify statistical significance per pixel Increase surface resolution of gamma’s (15 o by early May – 8 o at poles) Use better epithermal map Incorporate HEND data ? Improve spectral analysis (norm to thermals / line fit…) Quantify gamma H-line  Quantification of abundances Future Developments

18. 2001 Mars Odyssey GRS 18 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping

19. 2001 Mars Odyssey GRS 19 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping K line (1.461 MeV) underlying continuum versus MOLA altitude Slope = 0.05 C/dt*km Offset =4.045 C/dt

20. 2001 Mars Odyssey GRS 20 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Si line (1.779 MeV) underlying continuum versus MOLA altitude Slope = 0.032C/dt*km Offset = 2.885C/dt

21. 2001 Mars Odyssey GRS 21 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping

22. 2001 Mars Odyssey GRS 22 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping

23. 2001 Mars Odyssey GRS 23 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Slope  E -1.6 Atmospheric correction I(h,E) = I 0 exp (-α. g) ¤ α (E) attenuation coefficient in cm2/g ¤ g (h) optical thickness in g/cm2 Using ρ(h)= ρ 0 exp (-h/10.8)

24. 2001 Mars Odyssey GRS 24 Workshop HEND - 2002 May 20 th – 22 nd 2002 Chemical elements preliminary mapping Atmospheric transmission: I (h,E) = I 0 exp (-α. g) g (h) optical thickness in g/cm 2 α (E) attenuation coefficient in cm 2 /g