In-situ Monitoring of Powder Density Using Terahertz Pulsed Imaging

We have developed an approach to investigate density variations in a moving powder bed by means of terahertz pulsed imaging. Terahertz measurements were acquired continuously during the rotation of a container filled with different grades of lactose and microcrystalline cellulose powder. Relative density distributions were resolved for different compaction stages of the powder, which indicated high variations of the powder density.