Fig. 6: Mass spectrum decomposition example.
From: Direct observations of negative ions on the Lunar surface by Chang'E-6
Data for energy bin e = 25 is shown. The signal is decomposed into electrons, negative hydrogen ions, negative oxygen ions, and accidental coincidences. The maximum likelihood estimate for negative hydrogen ions, defined in Eq. (3), gives an estimated total number of counts of \({\hat{\theta }}_{{{{{\rm{H}}}}}^{-}}\approx 40\). For H−, the significance limit computed from Eq. (8) is about 3 and the 90% confidence limits are \(\min \left({{{{\rm{CI}}}}}_{{{{{\rm{H}}}}}^{-}}\right)\approx 28\) and \(\max \left({{{{\rm{CI}}}}}_{{{{{\rm{H}}}}}^{-}}\right)\approx 54\). Accidental coincidences are not shown in the figure as their estimate is below the 10−2 count level. The fitted model agrees well over the whole range of mass bins mb (note that bins numbers without a data point shown contain zero values that can not be represented in the logarithmic scale).
