Goals & Objectives

The primary goal of the facility is to make electron microscopy accessible to anyone within Ogden College. This includes:

– keeping equipment in working order,

– instructing users on how to prepare and then view their samples,

– supervising trained users as they work.

Capabilities & Services

The facility has two electron microscopes: a JEOL 1400Plus transmission electron microscope (TEM) and a JEOL 6510LV scanning electron microscope (SEM).

TEM Imaging:

To image samples in the TEM, a beam of electrons is transmitted through a very thin sample ( <100 nm thick) mounted on a 3 mm diameter disk of copper screening (called a “grid”).

If the original sample is large, it must be embedded in plastic and then cut into 100nm slices with an “ultramicrotome” before placing on a grid.

If the original sample is already less than 100nm thick it can be:

– frozen in thin films of water in the holes in the grid, and observed frozen in the TEM,

– adhered to a thin film of plastic or carbon covering a grid, then dried and observed at room temperature.

The best resolution routinely obtained on our TEM is about 0.2nm.

SEM Imaging:

Images in the SEM are created one pixel at a time as a finely focused beam scans across a sample. For each spot, detectors measure “products” of the beam as it collides with the atoms in the sample– the more products detected from a spot hit by the beam, the brighter the corresponding pixel.

Our SEM has three detectors:

– a secondary electron detector– for imaging topography,

– a backscattered electron detector– for imaging composition (with heavier elements brighter)

– an x-ray detector– for imaging specific elemental distributions.

The best resolution routinely obtained on our SEM is about 10nm.

Samples can be large (up to 100mm in diameter and 40mm high) and at the lowest magnification (8x) an area on the sample as large as 16mm x 10mm can captured in one image.

Funding

Funding for the center comes from (in order of importance) the Ogden College Dean’s office, the Biology Department, from some grants, from donations from individual faculty members, and from revenue generated when local businesses use the SEM.