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Both corrupt the measured spectrum.","posed_since":"2010","precise":"Construct a detector response model giving the recorded energy spectrum from the incident one, including charge sharing between pixels of 200 to 500 micron pitch, K-escape of the sensor material, and pulse pileup at count rates of $10^{8}$ to $10^{9}$ counts per second per $\\mathrm{mm}^2$, accurate enough that material decomposition bias stays below 1 percent. 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