prolly coz computers got faster and can process data faster :) now and still improving :) next thing you know you will carry a supercomputer in your wristwatch ;)
I have worked on Stereoscan 250/600/... in the 80', we have always been able to get a "television" frequency for "low" resolution. Than, when it is about to take a picture, you lower the beam current and the scanning speed.
@Jay Izzett Yeah I was thinking about that why sucking some electrons will produce the corresponding image? I bet there'r massive image processing going on in the background so actual image is impossible?
exactly, it's not just some shapes from powerpoint thrown together to represent what's going on... you actually get to see the experiment being conducted/hardware being used - from start to finish. If only explanations of concepts were as pedagogically considered & realised like this, a lot of natural-physical science would be easy to understand, then you science literacy wouldn't be as difficult.
Clear very good explanation. Thank you. I used SEM in 1969 at RWTH Aachen for my Doktor work to study surface of iron ore after reduction with CO and H2. It revealed iron whiskers in different shapes and sizes and explained reason for abnormal swelling during reduction. Though I used it in 1969 today I understand with more clarity how SEM works from your video. Thank you.
Answer to "Clear very good explanation. Thank you. I used SEM in 1969 at RWTH Aachen for my Doktor work to study surface of iron ore after reduction with CO and H2. It revealed iron whiskers in different shapes and sizes and explained reason for abnormal swelling during reduction. Though I used it in 1969 today I understand with more clarity how SEM works from your video. Thank you." Thanks for the information. The work you describe is an excellent application for SEMs.
Great video. I actually ran one quite similar back in the early 1980's while working at a semiconductor manufacturer in San Jose - on Bubb road near Deanza college. I took step coverage micrographs of mil-spec parts along with the occasional insect. Wolf spiders up close have really big fangs! and bees eyes are incredible. But you need to be very careful or you can set them on fire and really mess up the internals - takes hours to clean and re align the collumn.
@@justintan7548 Yes, as long as an oxidizer is present things will burn in either a vacuum or underwater. Ever seen underwater welding or a rocket motor in space? Just think how hot a concentrated electron beam can get...
The image is much worse in realtime mode though, due to the practical and physical limitations. All SEMs have a high quality acquisition mode, which can take snapshots with good(presentable) resolution. Such scans take many seconds to complete, but you can get many megapixels out!
@@evolutionCEO Skepticism for the sake of skepticism isn't cute. Why do you think it's fake? Like for real, give me a reason. Because the image is too perfect?
Electron scanning microscope reminds me of a very similiar concept: like an upsided down vaccum electron tube, as in TV scanning cathode ray tube, but with more complicated controls inside to examine the specimens on the plate. Thanks to quantum mechanical physics!
Answer to "Electron scanning microscope reminds me of a very similiar concept: like an upsided down vaccum electron tube, as in TV scanning cathode ray tube, but with more complicated controls inside to examine the specimens on the plate. Thanks to quantum mechanical physics!" Yes, there are many similarities!
It's clearly Windows 2000. 3.x had up and down arrows for minimizing and maximizing windows and it had the dropdown context menu on the upper left. Anyway, the video is obviously from the 2000s.
It was my first time to watch a EM although I have completed my master degree in science...professor always used to say that EM cost is very high. I don't know what's the cost or price of this EM...
Thanks for providing an actual hands-on explanation of SEM .... to be frank, I did have an idea of what it does, but I think now I have a clear understanding of how it works too from this video 👍
The non-destructive chemical composition detection due to the type of emitted x-ray is freaking brilliant. Pieces of the puzzle become illuminated once you begin to construct the picture.
Yeah me too! I liked the Megalovania music playing the background of the video when Comic Sans started displaying on the screen! Oh.. Someone is knocking on my door.. Well, I just realised why. I forgot to pay rent today
they don't. The secondary electrons give you a signal you can use to construct the image by scanning a point across the sample and simultaneously on the view screen. The magnification comes about by changing the ratio between the scan size in the electron microscope (making it smaller) while keeping the scan size the same on the view screen.
How do the secondary electrons carry the image? This is super cool. Better than relying on reflection as with tradition light they can actually attract the image carrying electrons and convert them to light?
your thinking of the reflection electron microscope. The SEM has a single point that is moved in synchronicity with a second spot on a CRT Screen. This point is modulated (changed in brightness) with a signal from a detector within the microscope. This detector (usually a Everhart Thornley detector) attracts secondary (low energy) electrons knocked out of the sample by the primary electron beam (electron probe). These secondary electrons get converted to light by the Scintillator, then measured and converted to an electrical signal via a photomultiplier tube, amplified many thousands of times and sent to the CRT mentioned earlier. In Mördern machines the CRT is replaced by a ADC and a computer screen, but the basic principle still holds. The image is then build up by scanning the electron probe across the sample
Answer to "Excellent video and its simplified presentation, question: what is its last scale of observation.": Thanks a lot! If I understand you correctly, you are referring to the magnification. The best way to check this is by using the length scale bar on the screen. The length of the bar is specified directly above it.
Answer to "Can we measure the atomic diameter of an mater ?": Directly no, the resolution is not good enough to see atoms. But indirectly yes, by special diffraction techniques, which is a very special topic.
Answer to "If I had putten a piece of a muscle, would I have benn able to see sarcomer structure?": In principle, yes, but it is a problem for (water-containing) organic substances to be placed in a vacuum without being damaged. So you need a very complicated preparation of the muscle. Mostly one uses transmission electron microscopy on dried, embedded and very thinly cut samples.
Very informative, clearly explained and nicely demonstrated. Only thing i' didn't get was why the secondary electrons sometimes form a light spot and sometimes a dark spot on the raster image. Is it to do with the number of secondary electrons given off for instance or maybe the angle of the material to the beam of primary electrons?
Answer to "Is it to do with the number of secondary electrons given off for instance or maybe the angle of the material to the beam of primary electrons?" Both of it, and there are some more influences. Bright spot, when many secondary electrons are registered in the secondary electron detector, dark spot when only few electrons are registered. - Many secondary electrons are registered > at a thin part of the specimen > at an edge of the specimen > at an inclined spot of the specimen > and at a surface that is tilted towards the secondary electron detector - Few secondary electrons are registered > at a thick part of the specimen > at a flat spot of the specimen (perpendicular to the primary beam direction) > and at a surface that is tilted away from the secondary electron detector
Answer to "Only the first X-ray photon is necessary or does the device read the subsequent photons as well?": The best X-ray analysis is obtained with a long "capture time". Many thousands of photons are then analyzed, sometimes millions.
"Best explanation" is what came up to me too. Obviously I'm not the only one. Never understood what this word "scanning" means in the context of electron microscopes. Many thanks to the Hochschule of Karlsruhe.
I wish I could see it it in person and use it like her 😭! I just used the light microscope in my schools biology lab and It was fantastic!!!! Idk how amazing it would be to see through a microscope with the magnification of 250000 times !!!!
Answer to: "How is the number of secondary electrons detected by the SE detector enough information to create an image?" It really is enough information, and this is the principle. Many detected electrons: the corresponding image pixel is bright; few detected electrons: the corresponding image pixel is dark. But this has to be done point by point and pixel by pixel; for an image of 1 million pixels you need 1 million measurements.
Could you say that the beam causes the object at the point of incidence to glow? In a sense of glowing with rays of electrons, but not in a necessarily visible way? Only in a way detectable by the SE detector?
Answer to "Could you say that the beam causes the object at the point of incidence to glow? In a sense of glowing with rays of electrons, but not in a necessarily visible way? Only in a way detectable by the SE detector?": Yes, in this sense it is indeed a kind of glowing, but only in this sense. The temperature at the focus point on the surface is not very high (under typical conditions), only slightly above room temperature.
5:30 "many recordes secondary electrons lead to bright point ... none to a black point" Clear, but how translates the structure of a specimen (which is what we want to see) to more or less emitted secondary electrons? Is it because parts of the structure are hidden to the primary electron beam, so something like shadow for sunlight?
@Ian Stevenson Okay, thank you for the clarification. Had to read it 2 times (I'm not a physicist), but it is clear now. One thing is more obvious then it was before: a SEM is a remarkable tool, both in how it works and what it reveals. *That's* what our brains are made for: not for fighting wars and denying viral outbreaks. Thanks again!
when an electron of the test object is explled out by the electon beam, doesn't the test object's property change? Due to certain electron configuration the object is defined. Now that it has lost the electron does the object remain the same it was before testing? From the results it is obvious the test object remains same. What is actually happening to the test object, when its electrons are explled out by the electron beam?
Answer to "when an electron of the test object is expelled out by the electon beam, doesn't the test object's property change? Due to certain electron configuration the object is defined. Now that it has lost the electron does the object remain the same it was before testing? From the results it is obvious the test object remains same. What is actually happening to the test object, when its electrons are expelled out by the electron beam?": To the best of my knowledge, an atom really changes its properties a lot, when an inner electron is expelled. However, (i) the number of these atoms (or rather special ions) in proportion to all other atoms in the specimen is small, and (ii) this state is highly instable, the atom repairs itself extremely quickly by the jumps of electrons from the outer shells into the inner shells. So we do not observe any change of properties in the case of metals in a SEM. This is quite different when organic materials (humans, flora, fauna, also polymers) are exposed to fast electrons. Then properties are changed a lot, mostly in a negative way.
Amazing how just 'counting' the secondary electrons over time from a tiny portion of the sample manages to reconstruct an image that looks so much like a magnified image of the sample. In fact from this point of view it doesn't make sense to me; the incoming beam of electrons (wherever it is aimed) is going to come into contact with atoms of the sample of the surface - its going to knock out secondary electrons that will be picked up so how is it giving such amazing resolution?
Answer to "... In fact from this point of view it doesn't make sense to me; the incoming beam of electrons (wherever it is aimed) is going to come into contact with atoms of the sample of the surface - its going to knock out secondary electrons that will be picked up so how is it giving such amazing resolution?": The "trick" is to focus the primary electron beam extremely. The diameter of the beam on the sample surface must be smaller than the distance between one scan point and the next. I hope this helps. ":
Ask me any questions. I am a senior field service engineer with Hitachi. I install, service, maintain and most importantly train my customers on how to use electron microscopes.
Arslan. No, only black and white images are created by this type of microscope, as the electrons collected don't contain any "color" information. They can, of course be artificially colorized after, using image processing software - typically by assigning a particular color to a specific brightness level.
See Tim's reply below, he is correct. Any color that you see on an electron microscope image has had image processing after the image has been captured. In published reports, this is typically not done because scientific studies do not like alterations to an original captured image. Color is normally added for illustration purposes only, and to make it look less boring when these captured images are being shown to people in meetings, etc, because usually these people will have no idea what they are looking at.
Answer to "Why didn't we see any micro-organisms on the sample materials? Were they sterilized somehow before being put in the chamber?" We clean all objects thoroughly before investigating them in the SEM. But even without cleaning the objects, it is difficult to see micro-organisms in the SEM. This is mainly because of the vacuum: the organisms die, they dry, they deteriorate … To view them in the SEM, special preparation techniques are necessary. Among many techniques the simples one is to dry the object and then coat it with a thin layer of an electrically conductive material, such as gold.
Answer to "Why different areas of the sample emit different amount of secondary electrons?": This is an interesting and very important point. In general, more secondary electrons are emitted in dense materials, and also at sharp edges. I must omit the explanations, they are much too long for this forum, sorry. "And why does more secondary electrons means a brighter image?": This is a completely free decision made by the manufacturer of the SEM. But it is a good decision, because it leads to a "normal looking" image that resembles an optical image. One could also decide to go the other way and create dark pixels at locations where many secondary electrons are emitted. However, this would not look "normal", but more like a negative (inverted) image.
Answer to "I need to know if this technique be used for Mineral analysis ?": Yes, minerals can principally be analysed as well. Since most minerals are electrical insulators, the test pieces normally have to be coated with a very thin layer of carbon or gold before being analysed. Unfortunately, this leads to a reduction in accuracy.
how did reverse beam hiding? 5:38 - first row and then second.. but the beam was not hided, it scrolls all over the material going back and smash the picture
Answer to "how did reverse beam hiding? 5:38 - first row and then second.. but the beam was not hided, it scrolls all over the material going back and smash the picture": There are several ways to overcome this problem. - The beam can jump extremely fast to the new position - The sampling of secondary electrons only starts, when the new position of the beam has been reached - The beam may be "switched off" temporarily (beam current reduced)
Any researcher in the field can answer this question please. Why can't X-ray radiation spectrum analysis could be used to identify the corona like virus different from other viruses. Is is harder to train a classifier , or the resolution is not enough to mathematically classify from other viruses.
Do the tests identify CORVID-19 strain specifically, given that most people have coronaviruses of all variations. The only way you can determine the numbers of coronavirus 19 carriers is by distinguishing them from the others. If the tests don't to that, then how do they arrive at the conclusion that people have caught this specific virus?
This is a. Practical based knowledge. I. Wish you can conduct a Short Course on the use of SEM. We in developing world neeeds it. Also, I need a copy of this clip and any other. I appreciate this, please keep it up. Bright Igwe, Nigeria
I've always thought that how things look in an electron microscope is REALLY cool! except when you are magnifying creepy looking things like bugs and other such creatures. LOL
Answer to "How much do Electron Microscopes cost?":SEMs range from around 50000 $ to about 2000000 $, depending on the "extras". Ours is a mid-range microscope for 250000 $.
If we see a small bacteria or a lifeless object in ordinary microscope , we can see the color shape etc. But in EM, do we see the actual specimen or an image ? In this video while focussing on the filament , initially it appeared like a filament we will be able to see with naked eyes but after some more closer focussing , the shape has become like an animation ... There seems some thing that is missing here. When does the animation part start?
Answer to "If we see a small bacteria or a lifeless object in ordinary microscope , we can see the color shape etc. But in EM, do we see the actual specimen or an image ? In this video while focussing on the filament , initially it appeared like a filament we will be able to see with naked eyes but after some more closer focussing , the shape has become like an animation ... There seems some thing that is missing here. When does the animation part start?": The working principle of the SEM is shown in the animation at the beginning. After the animation, only real images of the sample are shown at different magnifications. These images are "real" in the scientific sense, but they are always in black and white and sometimes look "synthetic", like an animation.
Answer to "Hold on. So isn't this basically like the CRT TVs, but with a higher voltage for the x-rays to generate, and the raster detector part?": Thanks, yes, this is the case, there are many similarities!
I have that exact same as Samsung monitor. The resolutions weird to its got like 200 extra rows of pixels at the bottom period more than it would need for 1080P and I'm not really sure why they have that
Answer to "is the detector really attract the electron? how the scope sppost to measure if the way the electron travel changed?" Yes, the detector really attracts the secondary electrons, and the travel path can vary a lot. But this does not matter, as long as the travelling time is small in comparison with the measuring time for each spot on the specimen.
If you're asking about SEM in general and not about one showed in video then past 1nm (0.4..0.2nm definitely possible) per pixel is achievable/possible today.
Answer to "How they determine shape by collecting only electrons?: By comparing the pixel position in the recorded picture with the position of the electron beam within the scan region - works nicely.
The way I understand it is, it's more changing the shade of the pixel by how many electrons get kicked (secondary electrons) off from the electron beam. Think of it as 0 electrons = black, 1 = very very dark gray, 5= very dark gray 10= gray etc. of course that's not the actual numbers but you get the point. The way they put that into a single image is they do that across the whole thing, they start with a tiny part of the top left corner of the specimen, get the information (how many electrons fly off and what shade the pixel would be) and put it in the top left corner of the screen, they do this till they get the whole specimen scanned.
@Ian Stevenson I see, thank you. I actually forgot I left this comment, and for a bit didn't understand what I was talking about. Hah, maybe I got dumber or something than last year, lol. I should probably revisit this topic
so in general, the scanning electron microscope work just like a typical cathode ray tube (CRT) television. where the image is formed by bombarding the specimen with high velocity electron. and scanned the specimen in raster ways, just like a printer. but the intricate science behind those machine is super amazing.
I'm amazed they can see the image in real time. I always imagined the image taking extraordinary long amounts of time to process.
me too
probably that was true until recently?
prolly coz computers got faster and can process data faster :) now and still improving :) next thing you know you will carry a supercomputer in your wristwatch ;)
The higher resolution images require a slower raster.
I have worked on Stereoscan 250/600/... in the 80', we have always been able to get a "television" frequency for "low" resolution. Than, when it is about to take a picture, you lower the beam current and the scanning speed.
It blows my mind that somebody figured all this out.
The interesting part is that someone can make a low quality one in his/her garage with only a couple thousand dollars in materials.
So much of this vid is theory sonic. Don’t be too mind blown .. damn deceivers
IKR
@@garethbaus5471 That's exactly what I'm looking for. Do you have a link to some online resource for that?
@Jay Izzett Yeah I was thinking about that why sucking some electrons will produce the corresponding image? I bet there'r massive image processing going on in the background so actual image is impossible?
best explanation of electron microscope on youtube
yup
exactly, it's not just some shapes from powerpoint thrown together to represent what's going on... you actually get to see the experiment being conducted/hardware being used - from start to finish.
If only explanations of concepts were as pedagogically considered & realised like this, a lot of natural-physical science would be easy to understand, then you science literacy wouldn't be as difficult.
I thought the same Time2Split. This could have been a dull presentation where my mind would wander. This was much better.
Good explanation,thank u
@@umamaheewaripolinati6752 so is there x rays detection
Clear very good explanation. Thank you. I used SEM in 1969 at RWTH Aachen for my Doktor work to study surface of iron ore after reduction with CO and H2. It revealed iron whiskers in different shapes and sizes and explained reason for abnormal swelling during reduction. Though I used it in 1969 today I understand with more clarity how SEM works from your video. Thank you.
Answer to "Clear very good explanation. Thank you. I used SEM in 1969 at RWTH Aachen for my Doktor work to study surface of iron ore after reduction with CO and H2. It revealed iron whiskers in different shapes and sizes and explained reason for abnormal swelling during reduction. Though I used it in 1969 today I understand with more clarity how SEM works from your video. Thank you." Thanks for the information. The work you describe is an excellent application for SEMs.
@@MaterialsScience2000
Spin of Indivisible Particle : Watch...
ua-cam.com/video/nnkvoIHztPw/v-deo.html
Xxxxx
If theres ever an apocalypse im just gonna break into a lab with one of these and play around until i get killed
why dont you just buy one
@@can_uysal Probably because those really high-tech ones are $60,000+.
@@Shock_Treatment probably im just joking
SoulsOfWolves lot more than that
@@nikolausdeems1922 Plus the Lab you have to set up
Great video. I actually ran one quite similar back in the early 1980's while working at a semiconductor manufacturer in San Jose - on Bubb road near Deanza college. I took step coverage micrographs of mil-spec parts along with the occasional insect. Wolf spiders up close have really big fangs! and bees eyes are incredible. But you need to be very careful or you can set them on fire and really mess up the internals - takes hours to clean and re align the collumn.
wow! that's really interesting
It can catch fire even in a vacuum?
@@justintan7548 Yes, as long as an oxidizer is present things will burn in either a vacuum or underwater. Ever seen underwater welding or a rocket motor in space? Just think how hot a concentrated electron beam can get...
Thank you for the fine job explaining the basics of how a scanning electron microscope works, including the great pictures. Cheers!
The finest and exact explanation of working of an electron microscope ever!
very nice and clear presentation. The metal analysis section was a nice bonus!
Never would've imagined the microscope is moveable and magnifyable in real time. Holy shit.
+1
The image is much worse in realtime mode though, due to the practical and physical limitations. All SEMs have a high quality acquisition mode, which can take snapshots with good(presentable) resolution. Such scans take many seconds to complete, but you can get many megapixels out!
You are happy that this is real? Looks faker than elon musks "car in space"...
Same. I've taken at least 2 classes that taught electron microscopy but never knew you could get a real time image like that! Incredible!
@@evolutionCEO Skepticism for the sake of skepticism isn't cute. Why do you think it's fake? Like for real, give me a reason. Because the image is too perfect?
A great explanation for people without Engineering degrees. Thank You
Electron scanning microscope reminds me of a very similiar concept: like an upsided down vaccum electron tube, as in TV scanning cathode ray tube, but with more complicated controls inside to examine the specimens on the plate. Thanks to quantum mechanical physics!
Answer to "Electron scanning microscope reminds me of a very similiar concept: like an upsided down vaccum electron tube, as in TV scanning cathode ray tube, but with more complicated controls inside to examine the specimens on the plate. Thanks to quantum mechanical physics!" Yes, there are many similarities!
i have waited too long to watch this video, only found it just now, great presentation of information!! thank you
I worked with an SEM as part of my microbiology degree. Brilliant piece of kit.
I've seen one been used in real time
It is absolutely mind blowing
8:46 When your nearly $1,000,000 scanning electron microscope is run by Windows 3.1, LOL.
It's clearly Windows 2000. 3.x had up and down arrows for minimizing and maximizing windows and it had the dropdown context menu on the upper left. Anyway, the video is obviously from the 2000s.
Muonium From 2011
the older the windows the more stable it is, that's what you want when running simple applications
Doctor and scientist doesn't want update in middle of research.
🤣
6:33 On the surface of the weld, it looks calm and ready.
theres vomit on his already
You can stop bleaching your hair now. Hes a has been. Just another mumbling left snowflake pushover lol
well explained, sir. easy to understand, very good resolution n very systematic operation!
What a GREEEATTTTTT explanation!!!!! Now I'm like 300 thousand steps ahead to use SEM in my investigation!
It was my first time to watch a EM although I have completed my master degree in science...professor always used to say that EM cost is very high. I don't know what's the cost or price of this EM...
Thanks for providing an actual hands-on explanation of SEM .... to be frank, I did have an idea of what it does, but I think now I have a clear understanding of how it works too from this video 👍
Beautifully illustrated and awesomely shown.
The non-destructive chemical composition detection due to the type of emitted x-ray is freaking brilliant. Pieces of the puzzle become illuminated once you begin to construct the picture.
I know this instrument. You did a very good job of this presentation. I watched the whole thing.. great.
Nice explanation. Very useful to understand whole construction and working of SEM.
I always imagined a mad scientist in a hazmat suit using a electron microscope and here she is.
LOL, great i worked in a EM facility lab for ten years, can't get enough of them!
Thank you! Very education and illustrative. Very clearly explained.
J.J Thompson must be smiling from the heaven.
Amazing technology!
Great presentation!
Great video, but what I like the most is the extensive use of comic sans.
Yeah me too! I liked the Megalovania music playing the background of the video when Comic Sans started displaying on the screen! Oh.. Someone is knocking on my door.. Well, I just realised why. I forgot to pay rent today
Nvm sorry for the confusion! I just forgot to pay for my protection money
When I was an ojt for a semicon company. We have this kind of microscope use for product / failure analysis. I miss using this machine.
Superb what a explaination bro electron microscope costs more than a Lamborghini so we have to thank him because he made us to watch this microscope
But how exactly these secondary electrons can actually give a magnification?
Helo
they don't. The secondary electrons give you a signal you can use to construct the image by scanning a point across the sample and simultaneously on the view screen. The magnification comes about by changing the ratio between the scan size in the electron microscope (making it smaller) while keeping the scan size the same on the view screen.
Best video explanation on scanning electron microscopy.
How do the secondary electrons carry the image? This is super cool.
Better than relying on reflection as with tradition light they can actually attract the image carrying electrons and convert them to light?
your thinking of the reflection electron microscope. The SEM has a single point that is moved in synchronicity with a second spot on a CRT Screen. This point is modulated (changed in brightness) with a signal from a detector within the microscope. This detector (usually a Everhart Thornley detector) attracts secondary (low energy) electrons knocked out of the sample by the primary electron beam (electron probe). These secondary electrons get converted to light by the Scintillator, then measured and converted to an electrical signal via a photomultiplier tube, amplified many thousands of times and sent to the CRT mentioned earlier.
In Mördern machines the CRT is replaced by a ADC and a computer screen, but the basic principle still holds.
The image is then build up by scanning the electron probe across the sample
Thank you, this is very helpful in Police work, always.
Excellent video and its simplified presentation, question: what is its last scale of observation.
Answer to "Excellent video and its simplified presentation, question: what is its last scale of observation.": Thanks a lot! If I understand you correctly, you are referring to the magnification. The best way to check this is by using the length scale bar on the screen. The length of the bar is specified directly above it.
@@MaterialsScience2000 Yes; about magnification , Can we measure the atomic diameter of an mater ?
Answer to "Can we measure the atomic diameter of an mater ?": Directly no, the resolution is not good enough to see atoms. But indirectly yes, by special diffraction techniques, which is a very special topic.
@@MaterialsScience2000 OooH Yes, thanks for your valuable information.
When I win the lottery I am going to buy one of these.
don't forget the equipment needed to support the SEM and prepare the samples.
As a undergraduate student, I think it is the most easiest way to understanding the principle and procedure of SEM characterization of a sample
Amazing.
I have a question.
If I had putten a piece of a muscle, would I have benn able to see sarcomer structure?
Answer to "If I had putten a piece of a muscle, would I have benn able to see sarcomer structure?": In principle, yes, but it is a problem for (water-containing) organic substances to be placed in a vacuum without being damaged. So you need a very complicated preparation of the muscle. Mostly one uses transmission electron microscopy on dried, embedded and very thinly cut samples.
Very informative, clearly explained and nicely demonstrated. Only thing i' didn't get was why the secondary electrons sometimes form a light spot and sometimes a dark spot on the raster image. Is it to do with the number of secondary electrons given off for instance or maybe the angle of the material to the beam of primary electrons?
Answer to "Is it to do with the number of secondary electrons given off for instance or maybe the angle of the material to the beam of primary electrons?" Both of it, and there are some more influences.
Bright spot, when many secondary electrons are registered in the secondary electron detector, dark spot when only few electrons are registered.
- Many secondary electrons are registered > at a thin part of the specimen > at an edge of the specimen > at an inclined spot of the specimen > and at a surface that is tilted towards the secondary electron detector
- Few secondary electrons are registered > at a thick part of the specimen > at a flat spot of the specimen (perpendicular to the primary beam direction) > and at a surface that is tilted away from the secondary electron detector
Good ole edge effect.
@@MaterialsScience2000 could you elaborate little more on this. How is the depth of the sample i.e the steps, kinks, adatoms are analysed
Very interesting and very beautiful operator!
Only the first X-ray photon is necessary or does the device read the subsequent photons as well?
Answer to "Only the first X-ray photon is necessary or does the device read the subsequent photons as well?": The best X-ray analysis is obtained with a long "capture time". Many thousands of photons are then analyzed, sometimes millions.
@@MaterialsScience2000 Thanks for the answer, by the first first photon, I meant each one's first photon.
great job, crystal clear
"Best explanation" is what came up to me too. Obviously I'm not the only one. Never understood what this word "scanning" means in the context of electron microscopes. Many thanks to the Hochschule of Karlsruhe.
the stuff the people do is unbelieveable... what a beautiful technology
I wish I could see it it in person and use it like her 😭! I just used the light microscope in my schools biology lab and It was fantastic!!!! Idk how amazing it would be to see through a microscope with the magnification of 250000 times !!!!
Very informative. And what a pretty SEM user!
How is the number of secondary electrons detected by the SE detector enough information to create an image?
Answer to: "How is the number of secondary electrons detected by the SE detector enough information to create an image?" It really is enough information, and this is the principle. Many detected electrons: the corresponding image pixel is bright; few detected electrons: the corresponding image pixel is dark. But this has to be done point by point and pixel by pixel; for an image of 1 million pixels you need 1 million measurements.
So is it essentially like echo location but instead of sound mapping out an image it is electrons mapping out images from an extremely small space?
Could you say that the beam causes the object at the point of incidence to glow? In a sense of glowing with rays of electrons, but not in a necessarily visible way? Only in a way detectable by the SE detector?
Answer to "Could you say that the beam causes the object at the point of incidence to glow? In a sense of glowing with rays of electrons, but not in a necessarily visible way? Only in a way detectable by the SE detector?": Yes, in this sense it is indeed a kind of glowing, but only in this sense. The temperature at the focus point on the surface is not very high (under typical conditions), only slightly above room temperature.
5:30 "many recordes secondary electrons lead to bright point ... none to a black point"
Clear, but how translates the structure of a specimen (which is what we want to see) to more or less emitted secondary electrons?
Is it because parts of the structure are hidden to the primary electron beam, so something like shadow for sunlight?
@Ian Stevenson Okay, thank you for the clarification. Had to read it 2 times (I'm not a physicist), but it is clear now. One thing is more obvious then it was before: a SEM is a remarkable tool, both in how it works and what it reveals. *That's* what our brains are made for: not for fighting wars and denying viral outbreaks. Thanks again!
when an electron of the test object is explled out by the electon beam, doesn't the test object's property change? Due to certain electron configuration the object is defined. Now that it has lost the electron does the object remain the same it was before testing? From the results it is obvious the test object remains same. What is actually happening to the test object, when its electrons are explled out by the electron beam?
Answer to "when an electron of the test object is expelled out by the electon beam, doesn't the test object's property change? Due to certain electron configuration the object is defined. Now that it has lost the electron does the object remain the same it was before testing? From the results it is obvious the test object remains same. What is actually happening to the test object, when its electrons are expelled out by the electron beam?": To the best of my knowledge, an atom really changes its properties a lot, when an inner electron is expelled. However, (i) the number of these atoms (or rather special ions) in proportion to all other atoms in the specimen is small, and (ii) this state is highly instable, the atom repairs itself extremely quickly by the jumps of electrons from the outer shells into the inner shells. So we do not observe any change of properties in the case of metals in a SEM. This is quite different when organic materials (humans, flora, fauna, also polymers) are exposed to fast electrons. Then properties are changed a lot, mostly in a negative way.
Nice lecture on scanning electron microscopy .... thanks for ur adorable lecture .
Thanks a lot !!
Explained really well !! 👍
I never had such explanation of electron microscope before!
Amazing how just 'counting' the secondary electrons over time from a tiny portion of the sample manages to reconstruct an image that looks so much like a magnified image of the sample. In fact from this point of view it doesn't make sense to me; the incoming beam of electrons (wherever it is aimed) is going to come into contact with atoms of the sample of the surface - its going to knock out secondary electrons that will be picked up so how is it giving such amazing resolution?
Answer to "... In fact from this point of view it doesn't make sense to me; the incoming beam of electrons (wherever it is aimed) is going to come into contact with atoms of the sample of the surface - its going to knock out secondary electrons that will be picked up so how is it giving such amazing resolution?": The "trick" is to focus the primary electron beam extremely. The diameter of the beam on the sample surface must be smaller than the distance between one scan point and the next. I hope this helps.
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Nice & well explained. Thanks a lot.
what is the step-by-step process on how high-resolution image is used to identify elements
These things are so much fun to play around with.
If you've done so, I envy you more than you can fathom !
Best explanation of electron microscope
“You know, this is the largest electron microscope on the eastern seaboard.”
Excellent explanation of electron microscope. Thanks a lot.DrRahul Rohtak.India
Amazing conceptual explanation and demonstration
Where did the cobalt plate go? I was so excited and watched till the end :( Great video, thank you!
In the video it is mentioned that the plate is only used for calibration :)
Ask me any questions. I am a senior field service engineer with Hitachi. I install, service, maintain and most importantly train my customers on how to use electron microscopes.
Travis Rice Can a true color image be generated with an electron microscope?
Arslan. No, only black and white images are created by this type of microscope, as the electrons collected don't contain any "color" information. They can, of course be artificially colorized after, using image processing software - typically by assigning a particular color to a specific brightness level.
See Tim's reply below, he is correct. Any color that you see on an electron microscope image has had image processing after the image has been captured. In published reports, this is typically not done because scientific studies do not like alterations to an original captured image. Color is normally added for illustration purposes only, and to make it look less boring when these captured images are being shown to people in meetings, etc, because usually these people will have no idea what they are looking at.
Travis Rice Thanks
Travis Rice what's the most affordable way to obtain an SEM? even if it's an old used 1980 era SEM?
Why didn't we see any micro-organisms on the sample materials? Were they sterilized somehow before being put in the chamber?
Answer to "Why didn't we see any micro-organisms on the sample materials? Were they sterilized somehow before being put in the chamber?" We clean all objects thoroughly before investigating them in the SEM. But even without cleaning the objects, it is difficult to see micro-organisms in the SEM. This is mainly because of the vacuum: the organisms die, they dry, they deteriorate … To view them in the SEM, special preparation techniques are necessary. Among many techniques the simples one is to dry the object and then coat it with a thin layer of an electrically conductive material, such as gold.
Why different areas of the sample emit different amount of secondary electrons? And why does more secondary electrons means a brighter image?
Answer to "Why different areas of the sample emit different amount of secondary electrons?": This is an interesting and very important point. In general, more secondary electrons are emitted in dense materials, and also at sharp edges. I must omit the explanations, they are much too long for this forum, sorry.
"And why does more secondary electrons means a brighter image?": This is a completely free decision made by the manufacturer of the SEM. But it is a good decision, because it leads to a "normal looking" image that resembles an optical image. One could also decide to go the other way and create dark pixels at locations where many secondary electrons are emitted. However, this would not look "normal", but more like a negative (inverted) image.
I need to know if this technique be used for Mineral analysis ?
Answer to "I need to know if this technique be used for Mineral analysis ?": Yes, minerals can principally be analysed as well. Since most minerals are electrical insulators, the test pieces normally have to be coated with a very thin layer of carbon or gold before being analysed. Unfortunately, this leads to a reduction in accuracy.
Thanks
Can non-destructive method can be used to check real diamonds with the help of Electron Microscope?
Excellent video. Very interesting and informative video.
Mind blowing clear explanation again thank you sir
Can you please explain the sophisticated method to determine chemical composition in X-Ray analysis????
6:52 SCIENCE IS INTERESTING
This video is a masterpiece!
Would love to see any moving organism or virus in this
Appreciate the presentation. A good overview.
how did reverse beam hiding? 5:38 - first row and then second.. but the beam was not hided, it scrolls all over the material going back and smash the picture
Answer to "how did reverse beam hiding? 5:38 - first row and then second.. but the beam was not hided, it scrolls all over the material going back and smash the picture":
There are several ways to overcome this problem.
- The beam can jump extremely fast to the new position
- The sampling of secondary electrons only starts, when the new position of the beam has been reached
- The beam may be "switched off" temporarily (beam current reduced)
Any researcher in the field can answer this question please.
Why can't X-ray radiation spectrum analysis could be used to identify the corona like virus different from other viruses.
Is is harder to train a classifier , or the resolution is not enough to mathematically classify from other viruses.
Is there a different Scanning electron microscope for nanoparticles?
Do the tests identify CORVID-19 strain specifically, given that most people have coronaviruses of all variations. The only way you can determine the numbers of coronavirus 19 carriers is by distinguishing them from the others. If the tests don't to that, then how do they arrive at the conclusion that people have caught this specific virus?
RNA genetic sequence (proteins) is how, EM can only provide physical visibility of virus, can't identify specific virus
Wow! This is truly amazing...I love it😎
This is a. Practical based knowledge. I. Wish you can conduct a Short Course on the use of SEM. We in developing world neeeds it. Also, I need a copy of this clip and any other. I appreciate this, please keep it up. Bright Igwe, Nigeria
I've always thought that how things look in an electron microscope is REALLY cool! except when you are magnifying creepy looking things like bugs and other such creatures. LOL
How much do Electron Microscopes cost?
Answer to "How much do Electron Microscopes cost?":SEMs range from around 50000 $ to about 2000000 $, depending on the "extras". Ours is a mid-range microscope for 250000 $.
If we see a small bacteria or a lifeless object in ordinary microscope , we can see the color shape etc. But in EM, do we see the actual specimen or an image ? In this video while focussing on the filament , initially it appeared like a filament we will be able to see with naked eyes but after some more closer focussing , the shape has become like an animation ... There seems some thing that is missing here. When does the animation part start?
Answer to "If we see a small bacteria or a lifeless object in ordinary microscope , we can see the color shape etc. But in EM, do we see the actual specimen or an image ? In this video while focussing on the filament , initially it appeared like a filament we will be able to see with naked eyes but after some more closer focussing , the shape has become like an animation ... There seems some thing that is missing here. When does the animation part start?": The working principle of the SEM is shown in the animation at the beginning. After the animation, only real images of the sample are shown at different magnifications. These images are "real" in the scientific sense, but they are always in black and white and sometimes look "synthetic", like an animation.
Hold on. So isn't this basically like the CRT TVs, but with a higher voltage for the x-rays to generate, and the raster detector part?
Answer to "Hold on. So isn't this basically like the CRT TVs, but with a higher voltage for the x-rays to generate, and the raster detector part?": Thanks, yes, this is the case, there are many similarities!
Understood SEM. So how is STEM different?
I have that exact same as Samsung monitor. The resolutions weird to its got like 200 extra rows of pixels at the bottom period more than it would need for 1080P and I'm not really sure why they have that
It's really helpful with such clear illustration. Thank you!
3:48 He means Secrets
is the detector really attract the electron? how the scope sppost to measure if the way the electron travel changed?
Answer to "is the detector really attract the electron? how the scope sppost to measure if the way the electron travel changed?" Yes, the detector really attracts the secondary electrons, and the travel path can vary a lot. But this does not matter, as long as the travelling time is small in comparison with the measuring time for each spot on the specimen.
What power magnification can this do?
Upto 200,000 x magnification
If you're asking about SEM in general and not about one showed in video then past 1nm (0.4..0.2nm definitely possible) per pixel is achievable/possible today.
This video is wonderful, Thanks for preparing and sharing it
Sucha!! nice explanation loved it.❤
How they determine shape by collecting only electrons?
Answer to "How they determine shape by collecting only electrons?: By comparing the pixel position in the recorded picture with the position of the electron beam within the scan region - works nicely.
The way I understand it is, it's more changing the shade of the pixel by how many electrons get kicked (secondary electrons) off from the electron beam. Think of it as 0 electrons = black, 1 = very very dark gray, 5= very dark gray 10= gray etc. of course that's not the actual numbers but you get the point. The way they put that into a single image is they do that across the whole thing, they start with a tiny part of the top left corner of the specimen, get the information (how many electrons fly off and what shade the pixel would be) and put it in the top left corner of the screen, they do this till they get the whole specimen scanned.
@Ian Stevenson I see, thank you. I actually forgot I left this comment, and for a bit didn't understand what I was talking about. Hah, maybe I got dumber or something than last year, lol. I should probably revisit this topic
so in general, the scanning electron microscope work just like a typical cathode ray tube (CRT) television. where the image is formed by bombarding the specimen with high velocity electron. and scanned the specimen in raster ways, just like a printer. but the intricate science behind those machine is super amazing.
everybody gangsta until the flange is sucked off by a vacuum
Beautiful video, thanks.