Low-voltage backscattered electron imaging of non-coated biological samples in a low-vacuum environment using a variable-pressure scanning electron microscope with a YAG-detector

A variable-pressure scanning electron microscope (VP-SEM) equipped with a high-sensitive backscattered electron (BSE) detector of the YAG type was applied to studies of biological tissue samples. The rat kidney and trachea were fixed, dehydrated in ethanol, critical point-dried and examined in the VP-SEM under a specimen chamber pressure of 1 to 150 Pa. The high-resolution surface images of the non-coated specimens were obtained in a low-vacuum (1-20 Pa) environment at an accelerating voltage of 5 kV, while the images at 10-20 kV contained information beneath the surface of the specimens. The observation in the VP-SEM equipped with YAG detector in a low-vacuum (1-20 Pa) environment at low (3-5 kV) accelerating voltages is useful for the three-dimensional analysis of the surface morphology of biological non-coated samples.