| High Energy X-ray Spectrometer (HEX) |
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| The High-Energy X-ray spectrometer covers the hard X-ray region from about 30 keV to about 250 keV. This is the first experiment to carry out spectral studies of planetary surface at hard X-ray energies using good energy resolution detectors. High Energy X-ray (HEX) experiment is designed primarily to study emission in the above energy range due to radioactive decay of the 238U and 232Th in the lunar surface region. |
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| Science Objectives |
| The primary scientific objectives of HEX are: |
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To identify excess 210Pb in lunar Polar Regions due to transport of volatile 222Rn, a decay product of 238U. This will provide credence to the idea of transport of other volatile such as water to the polar regions. |
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To detect signal of other radioactivity via large area integration to characterize various lunar terrains for their chemical composition on the basis of specific/integrated signal in the 30-250 keV region. |
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To identify regions of high U/Th concentrations via detection of emission due to decay of Pb-212 and Pb-214 (~240 keV). |
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To explore the possibility of identifying chemical composition of various lunar terrain from a study of the scattered continuum background. |
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| Payload configuration Details: |
| The geometric detector area of 144 cm2 is realized by cascading nine Cadmium Zinc Telluride (CZT) arrays, each 4 cm x 4 cm (5mm thick), composed of 256 (16x16) pixels (size: 2.5 mm x 2.5 mm). Each CZT array is readout using two closely mounted Application Specific Integrated Circuits (ASICs), which provides self-triggering capability. An anticoincidence system is used to reduces the detector background. A specially designed collimator provide a field of view (FOV) of 40 km X 40 Km. The weight of HEX is about 16kg.
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| HEX payload developed by ISRO |
