The Material IMAGE: Microscopy in the Archive Official Opening on Monday, April 3, Guyon Auditorium
A collaboration between SIU Carbondale’s IMAGE Center, Morris Library, and Da Vinci Days
Created using samples from Morris Library’s Special Collections Research Center (SCRC), these images bring to life the vibrant worlds hidden in the stacks of the library’s rare books and archives. Leather, cloth, paper, film, and tape – the materials elements of the archive – become something new under the lens of SIU’s Integrated Microscopy And Graphics Expertise (IMAGE) Center’s electron microscope.
The IMAGE Center’s scanning electron microscope (SEM) differs from a standard microscope because it uses a beam of electrons instead of light to create an image. It also uses electromagnets instead of traditional lenses. SEMs produce images that have higher resolution, greater magnification, and greater focus than standard light microscopes. The samples in this exhibit were scanned with the IMAGE Center’s FEI Quanta 450 scanning electron microscope.
To create an image, a beam of electrons is scanned across a prepared sample which interacts with the prepared sample’s atoms at different depths. The image quality can be affected by several variables including the electron beam’s settings and sample preparation. The intensity of the electron beam can be controlled in part by the accelerating voltage level. Here, the acceleration voltage level was 10 kV. Another aspect that can influence the quality of the image is the working distance. The working distance is the distance that the beam is focused and can help control the size of the area that is imaged by the SEM. These samples were scanned with working distances varying from 10mm to 23mm. The magnification and working distance specifications can be seen on each image.
The electrons and X-rays that hit the sample produce various signals (that contain surface structure and composition) which are then detected and the image is produced on a monitor. These dispersed emissions can be secondary electrons, backscattered electrons, and X-rays. The process in this case used an Everhart-Thornley detector to detect these secondary electrons. This process occurs in a vacuum thus the samples must be completely dry. Here, these samples were scanned using a high vacuum (10^-3 Pa). If the sample to be scanned is non-conductive, it also must be prepared and coated with a thin layer (10-50nm) of a conductive material (such as gold, silver) before imaging. These samples were prepared on a stub with carbon tape and coated with gold/palladium using a Denton Vacuum. Some of the images were also processed with false coloring using Image J software, adding shades of green, purple, red, and yellow.
This exhibit is made possible with by the generous cooperation of the IMAGE Center’s Director, Dr. Punit Kohli, and Graduate Assistants Rajesh Balaraman, Milinda Wasala, and Nathalie Becerra. The samples were selected by the staff and faculty of Morris Library’s SCRC, including David Bond, Matt Gorzalski, Jessica Zieman, and Nicholas Guardiano. The exhibit was prepared by Morris Library’s Arts & Exhibits Committee: Sarah Prindle, David Bond, Jennifer Horton, Karen Wolf, Sharon Granderson, and Kerry Bowden, as well as Professor H. D. Motyl, organizer of Da Vinci Days 2017.
The IMAGE Center’s work is made possible by SIU’s Office of the Vice Chancellor for Research (OVCR) and the Department of Chemistry and Biochemistry, as well as the National Science Foundation, the National Institutes of Health, the U.S. Department of Agriculture, and the Binational Agricultural Research & Development Fund. And a special thank you to the Office of the Vice Chancellor for Research (OVCR) for making this exhibit possible as part of Da Vinci Days, a celebration of SIU’s innovation and creativity!