What is Transmission Electron Microscopy (TEM)?
TEM is a technique where a beam of electrons is transmitted through a thin sample, interacting as it passes through. An image is formed from the interaction of the electrons transmitted through the sample. This image is magnified and focused onto an imaging device and it is detected by a sensor such as a CCD camera. TEMs are capable of imaging at a significantly higher resolution than light microscopes, owing to the small wavelength of electrons, in comparison to light. This enables the examination of fine specimen detail - even as small as a single column of atoms.
What are the capabilities of the TEM?
In addition of obtaining Transmission Electron Microscopy images we are trained to obtain Scanning Transmission Electron Microscopy (STEM) images, Energy Dispersive X-ray Spectroscopy (EDS) Analysis and Dark Field TEM and STEM Images. Due to the camera configuration electron diffraction is not possible at the moment.
Can I use the TEM by myself to work with my samples?
Currently, only the CeNaC instrumentation specialist can work with your samples in the TEM. We are sure you will understand that these are expensive pieces of equipment, requiring extensive training to be able to use them and TEM access have to be requested at all times for all users using TEMs Request Form in our website.
Which sample preparation is recommended?
Sample preparation will depend on your type of sample. These processes and associated instrumentation include chemical fixation, embedding and ultra-thin sectioning of biological material, and the thinning of metal samples prior to TEM examination. The resultant samples are typically supported on TEM grids for observation. The primary training we have had in our TEM has been on inorganic materials which are more resilient to the electron beam and require minimal sample preparation. Currently we do not have any special preparation method available in the Center and we expect the users bring the samples already ready for observation.However, even on inorganic samples we have observed degradation of the sample and carbon deposition at the 200kV the instrument works on. Thus, organic samples dipped on a TEM grid is usually not enough to prevent their decomposition. There is a video on Youtube that discusses several sample preparation techniques for biological samples: https://www.youtube.com/watch?t=20&v=nkGRhYv01ag
Which TEM sample support grid is recommended?
We recommend the Ted Pella, Inc. 400 mesh copper grid (Product No. 01824) as it provides the highest transparency of the samples allowing better resolved images. For more specific information, see Resources tab in our website.
What is the fee to analyze my samples?
During fiscal year 2015-2016, after a merit evaluation we will be running the first samples of projects for free. However, subsequent samples will be charged $100 per experimental hour.
Can I visit the CeNaC with my school to see the TEM?
Yes. Contact us for a scheduled visit to our facilities.