Characterizing powders using frequency-domain photon migration
Abstract
Characterizing a powder bed includes generating measurements by repeating the following. A location of the powder bed is illuminated with light having a time varying intensity with a resolution of less than one hundred nanoseconds. The particles scatter the light to alter the time varying intensity. The light propagates through a portion of the particles that defines a sampled volume. The light received from the powder bed is detected. The altered time-varying intensity of the light is measured to generate a time-dependent signal having a time-dependence that is less than or equal to a time-of-flight of a photon of the propagating light. An optical property is determined from the time-dependent signal, and a characteristic is determined from the optical property. The sampled volume is determined, and variance of the measurements is calculated. Uniformity of the powder bed is determined in accordance with the variance and the sampled volume.
Subject
356/336356/342
G01N 15/0211
G01N 21/51
G01J 3/4412
G01N 2015/0096
G01N 2015/0216
G01N 2015/0222
G01N 2021/4797
G01N 2021/8592
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Citation
Sevick-muraca, Eva M.; Sun, Zhigang; Pan, Tianshu (2004). Characterizing powders using frequency-domain photon migration. United States. Patent and Trademark Office; Texas A&M University. Libraries. Available electronically from https : / /hdl .handle .net /1969 .1 /176761.