A radiation detector having a sensitive area of Ad 4 106

Chapter , Problem 12.88

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A radiation detector having a sensitive area of Ad 4 106 m2 is configured to receive radiation from a target area of diameter Dt 40 mm when located a distance of Lt 1 m from the target. For the experimental apparatus shown in the sketch, we wish to determine the emitted radiation from a hot sample of diameter Ds 20 mm. The temperature of the aluminum sample is Ts 700 K and its emissivity is s 0.1. A ring-shaped cold shield is provided to minimize the effect of radiation from outside the sample area, but within the target area. The sample and the shield are diffuse emitters. (a) A (a) Assuming the shield is black, at what temperature, Tsh, should the shield be maintained so that its emitted radiation is 1% of the total radiant power received by the detector? (b) Subject to the parametric constraint that radiation emitted from the cold shield is 0.05, 1, or 1.5% of the total radiation received by the detector, plot the required cold shield temperature, Tsh, as a function of the sample emissivity for 0.05 s 0.35.