Design of a pilot-scale microwave freeze dryer for in situ neutron imaging.

The gentle yet cost-effective drying of sensitive products in the food and pharmaceutical industries is becoming increasingly important. To maintain sensitive ingredients, color, structure, and viability of micro-organisms, often freeze-drying is the only possible way to preserve the product. As many products come in as bulk material, they are dried on heated shelves resulting in poor heat and mass transport through the bed.

Development of an experimental setup for in situ visualization of lyophilization using neutron radiography and computed tomography.

This article shows a new conceptional design of an experimental setup for in situ visualization of the lyophilization process using neutron radiography and computed tomography and its validation. The setup is designed for the neutron imaging beam line ANTARES at FRM II, considering all the requirements for this method. Neutrons are ideally suited to detect water in a sample because of the high neutron attenuation of hydrogen, whereas other materials like aluminum have a low absorption of neutrons resulting in an image where the drying fronts in bulk materials are observable.