NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
The technique described here, utilizing the sharpness concept, is facilitated by the use of the FFT techniques to analyze the electron micrograph to obtain the evaluation. This is not the first application of Fourier techniques to SEM images, but it is the first integrated approach considering the sample, computer analysis and measurement algorithm. This technique can be used to check and optimize two basic parameters of the primary electron beam, the focus and the astigmatism and it facilitates the periodic resolution determination of the SEM in an objective and quantitative form.