Abstract Details
| Name: subramania athiray Affiliation: manipal centre for natural sciences Conference ID: ASI2016_686 Title : Study of lunar surface chemistry using Swept Charge Devices Authors and Co-Authors : P. S. Athiray, Manipal Centre for Natural Sciences Abstract Type : Oral Abstract Category : Thesis Abstract : Studying the surface chemical composition of the Moon is of prime scientific importance as it preserves record of early geological history of the solar system. This thesis investigate the chemical composition of lunar surface through X-ray Fluorescence (XRF) technique, utilizing data from the Chandrayaan-1 X-ray Spectrometer (C1XS) on board Chandrayaan-1. C1XS experiment was designed to map the distribution of abundances of major rock-forming elements viz., Mg, Al, Si, Ca, Ti and Fe on the lunar surface. A detailed summary of entire C1XS observations, data selection methods and spectral analysis procedures are explained. This thesis demonstrate the first direct detection and quantification of moderately volatile element Sodium (Na) on the lunar surface. An independent XRF inversion algorithm 'x2abundance', that can convert XRF line intensities to elemental abundances is detailed. Validation of 'x2abundance' using laboratory XRF experiments and GEANT4 simulations with metal alloys and lunar analog rocks are explained in detail. Lunar surface elemental abundances are determined for the C1XS-observed regions using the inversion algorithm. New insights from C1XS results and its scientific significance on lunar surface studies are presented. The need for an improved global surface elemental mapping of the Moon and the development of Chandrayaan-2 Large Area Soft x-ray Spectrometer (CLASS) on board the upcoming Chandrayaan-2 mission have also been discussed. As the C1XS and CLASS experiments employ Swept Charge Devices (SCD) as X-ray detectors, a charge transport model is developed to better understand and predict the spectral redistribution function of SCD. Algorithm development, implementation and successful validation with C1XS ground calibration data are described. This Monte Carlo simulation will be quite useful during the calibration of X-ray detectors for the CLASS instrument. In the end, new developments with a few X-ray instrumental design aspects which can potentially improve surface investigation of Moon/airless planetary bodies in X-rays are discussed. |