The most common imaging mode collects low-energy (<50 eV) secondary electrons that are ejected from the k-shell of the specimen atoms by inelastic scattering interactions with beam electrons. Due to their low energy, these electrons originate within a few nanometers from the sample surface.[14] The electrons are detected by an Everhart-Thornley detector,[29] which is a type of scintillator-photomultiplier system. The secondary electrons are first collected by attracting them towards an electrically biased grid at about +400 V, and then further accelerated towards a phosphor or scintillator positively biased to about +2,000 V. The accelerated secondary electrons are now sufficiently energetic to cause the scintillator to emit flashes of light (cathodoluminescence), which are conducted to a photomultiplier outside the SEM column via a light pipe and a window in the wall of the specimen chamber. The amplified electrical signal output by the photomultiplier is displayed as a two-dimensional intensity distribution that can be viewed and photographed on an analogue video display, or subjected to analog-to-digital conversion and displayed and saved as a digital image. This process relies on a raster-scanned primary beam. The brightness of the signal depends on the number of secondary electrons reaching the detector. If the beam enters the sample perpendicular to the surface, then the activated region is uniform about the axis of the beam and a certain number of electrons "escape" from within the sample. As the angle of incidence increases, the interaction volume increases and the "escape" distance of one side of the beam decreases, resulting in more secondary electrons being emitted from the sample. Thus steep surfaces and edges tend to be brighter than flat surfaces, which results in images with a well-defined, three-dimensional appearance. Using the signal of secondary electrons image resolution less than 0.5 nm is possible.

Hi, thanks for a great blog. In our office we have a debate going on about whether all of this video hype that we’re experiencing from basically everywhere today is really just, well, a hype.. In line with more and more companies using video marketing, text as we know it might fade out, pictures as we know them might fade out, but if everybody starts using video, what will then happen? Today, video is commonly seen as a way to stand out and capture users’ attention, but what if every brand start publishing video solely? Will we still want to see as much video? Will we need to capture the viewers’ attention in 2 seconds instead of 10? What do you think it requires for companies to succeed with videos and stay on top if everybody else is doing the same?
Prioritizing clicks refers to display click ads, although advantageous by being ‘simple, fast and inexpensive’ rates for display ads in 2016 is only 0.10 percent in the United States. This means one in a thousand click ads are relevant therefore having little effect. This displays that marketing companies should not just use click ads to evaluate the effectiveness of display advertisements (Whiteside, 2016).[42] https://www.youtube.com/watch?feature=player_embedded&v=e29F5n3ea0I
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