How do I read a scanning electron microscopy (SEM) image? I'm trying to figure out the magnification of this image. Can anyone explain how to read the numbers at the bottom? What do they mean and how can I determine the magnification from them?

 A: The magnification is 1,500 which is displayed at bottom of the image. If you want to know the object size from the image, there are 2 methods.


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*How to know directly the size using SEM. In this SEM image, type of SEM is displayed. That is S3400. S3400 is made by HITACHI. For this SEM system, a data analysis software is installed. So you can know the size using the software.

*How to know the size from SEM image. In generally, when SEM is installed to lab and room, the scale bar is calibrated for each magnification by administrator or stuff of the maker. The calibration is usually regularly carried out. So the scale bar of the bottom of image can be believed. If the calibration of scale bar is not carried out, it is necessary to do for knowing the size of objects in the SEM images.
The scale bar is the right bottom of image. There are constructed with 10 short lines. All lines means 30 um. So you can know the object size using this scale of 30 um.
9.9 mm is working distance. The working distance is the distance between the objective lens and a sample.
I comment here, because I couldn't add a comment.
A: *

*The magnification is stated as x1.50k. What you are looking at was magnified 1500 times.

*The white strips on the right look like a used-to-be length scale. Maybe it was cut in half by mistake - I've never seen a scale this unclear. There are 11 small equaly spaced lines, which fits to a length scale subdivided in 10 parts.
The value 30 um is then the full length of the scale at $30\;\mathrm{\mu m}$. This fits when comparing magnitude to length scale with similar SEM images, for example this from Wikipedia:
https://upload.wikimedia.org/wikipedia/commons/1/17/Cobaea_scandens1-4.jpg
The other values and information are specific for the apparatus or the specific conditions used to take the photo. You will have to know more details from the manual or software setup.


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*15.0 V is the energy set to accelerate the electrons in the electron beam when shooting onto the sample.

*60 Pa might be the vacuum pressure. If vacuum is not established, the images will be non-viewable. This value might tell something about risk of noise.

*S3400 and BSECOMP must be some labels refering to type of software or machine or a sample added name by you e.g.

*I do not know what the 9.9mm tells. Maybe also just some manually added info about sample size?

A: 9.9mm is the working distance(WD) between sample and the lens and it is zoomed to  1.50K from WD.
