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This study presents early mapping results of hydrogen, potassium, and silicon using gamma lines. The data sets include raw gamma data, spectra analysis, background mapping, correlation analysis, and future development plans. The study aims to improve mapping accuracy and incorporate additional data sources for better understanding of the elements' distribution.
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Early Mapping of Hydrogen,Potassium and Siliconfrom the Gamma lines L. d’Uston, S. Maurice, O. Gasnault
Gammas Raw data from Query Tool (gammaspatial + engineering) Time selection: Feb 20 – March 9 before annealing Temperature selection: GRS_IS_TEMP_A < -165oC 2 weeks 55,972 spectra (~304 hours) Neutrons Press release data from W. Feldman & R. Tokar Data sets
Spectral Analysis 2.0 MeV Continuum H-line 2.4 MeV (counts/19.6 sec) Background Energy 2.215 – 2.230 MeV Energy callibration [W. Boyton, Feb 02] Slope = 0.6152 keV/channel Intercept = 18.86 keV
Mapping at 30o resolution (equal area) Application of the Mapping/Display Toolkit (8) (8) (12) (12) (15) Min = 530 spectra
Background with MOLA Below –45o Above +45o Effects of atmospheric Absoption
Map of background (corrected for 0 km MOLA altitude) (same color range)
Epithermal neutrons [Press release data] ! Arb. Units = constant - epithermals ! Smooth 4o
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 Future Developments • Quantify statistical significance per pixel • Increase surface resolution of gamma’s (15o by early May – 8o at poles) • Use better epithermal map • Incorporate HEND data ? • Improve spectral analysis (norm to thermals / line fit…) • Quantify gamma H-line Quantification of abundances
K line (1.461 MeV) underlying continuum versus MOLA altitude Slope = 0.05 C/dt*km Offset =4.045 C/dt
Si line (1.779 MeV) underlying continuum versus MOLA altitude Slope = 0.032C/dt*km Offset = 2.885C/dt
Atmospheric correction I(h,E) = I0 exp (-α. g) ¤ α (E)attenuation coefficient in cm2/g ¤ g (h)optical thickness in g/cm2 Using ρ(h)= ρ0 exp (-h/10.8) Slope E-1.6
Atmospheric transmission: I(h,E) = I0 exp (-α. g) g (h) optical thickness in g/cm2 α (E) attenuation coefficient in cm2/g