Week+of+Sep+15


 * Sep 15, Monday**

Okay, today I'll try to finish listing the observations from last Thursday and form some foundation for my SEM web. (eventually, all these scattered ideas below will go into my SEM web nicely and neat.) For some reason, I felt very drowsy all weekend... It might be because it was raining all weekend. I desperately wanted to see the SUN. My Sweet sun that brightens my brain. Anyway, today, here is the sun and I'm in a very good mood :) Anyway to get to the point, I saw how mini SEM works on Thursday. It was quite long procedure because it took some time to operate the SEM. Unlike some other equipment, this SEM needed time to establish a favorable environment to start. For example, after we turned on the D.P., we waited approximately 15 minutes to warm up the oil to produce the vapor. (the listing might not be clear. I'm just going to jot down the notes that I took during the observation. These are just scattered ideas for now)

-D.P. is starting to work - in order to have rotary pump to grab that thing (?) -less than 10 micron -diffusion pump was off -> volume thingy? //When the primary electron beam interacts with the sample, the electrons lose energy by repeated random scattering and absorption within a teardrop-shaped volume of the specimen known as the interaction volume, which extends from less than 100 nm to around 5 µm into the surface. The size of the interaction volume depends on the electron's landing energy, the atomic number of the specimen and the specimen's density. // -pressure on the pump itself, not on the chamber (watch the change of rotary pump's number) - wait until the operation light is on. -favorable condition <10 ^ -3 ___*here, micron is the standard measurement. -turning the column on by turning right -green light was turned on, # goes up and comes down -operation : stablizing the video -turning up the emission -hit up the tungsten filament (until it reaches 120 micron) -> produces electron -> filament current           //Tungsten is normally used in thermionic electron guns because it has the highest melting point and lowest vapor pressure of all metals, thereby allowing it to be heated for electron emission, and because of its low cost. // -magnification ........ (we were looking at the very tiny circuit) //Magnification in a SEM can be controlled over a range of about 5 orders of magnitude from x25 or less to x 250,000 or more. Unlike optical and transmission electron microscopes, image magnification in the SEM is not a function of the power of the objective lens.// -opening the aperture - reading the outcome is not working so great ( I remember that our reading was not so great. It does not mean that the equipment is not working great but we had some problems on TV connected to the SEM that shows the result) - when you want to look some stuffs, put in into the column <span style="color: rgb(0, 84, 255); font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif">//All samples must also be of an appropriate size to fit in the specimen chamber and are generally mounted rigidly on a specimen holder called a specimen stub. Several models of SEM can examine any part of a 6-inch (15 cm) semiconductor wafer, and some can tilt an object of that size to 45 degrees.// <span style="color: rgb(16, 86, 213); font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif"> -Column : cannot open now ( I mean, during the experiment) because we're in the process right now. -showed electrons reaching that surface (detector) -> to prevent electrons colliding with air molecules-> making it as a vacuum space <span style="color: rgb(0, 84, 255); font-family: 'Lucida Sans Unicode','Lucida Grande',sans-serif">//Conventional SEM requires samples to be imaged under vacuum, because a gas atmosphere rapidly spreads and attenuates electron beams.// - bouncing off the electron to the detector -> turn down the emission - when filament is exposed to the atmosphere, it will burn down -emission control : control it slowly, not at once. 120 (?) -when we pull that thing out, I could hear the sound of atmosphere released. -It was about 8 (rotary pump) -shut down : similar step as we did for starting up the equipment. -turn off emission and operation -shut position : locks the vacuum to column -turn off D.P : let that cool off for approximately 15 minutes (four line)? - we can let the air in -emission down first, and then the switch can be turned off.
 * - SEM plays crucial role in surface analysis**

We did our little experiment with a very little circuit which looked huge through the screen but it would be very interesting that if we could explore with piano wires, or insects **(//A biological specimen normally requires chemical fixation to preserve its structure.//**). That would be my goal for now? I'm really interested in looking piano wires using SEM. That would be AWESOME!!! :DD

<span style="background-color: rgb(226, 223, 223)">**More ORGANIZED Note**

 * The Scanning Electron Microscope, or SEM, plays pivotal role in seeing the unrevealed worlds of micro-space.
 * Conventional light microscopes use a series of glass lenses to bend light waves and create a magnified image.
 * [[image:square.gif caption="How Image is produced" link="http://www.nd.edu"]]
 * The Scanning Electron Microscope creates the magnified images by using electrons instead of light waves.
 * The SEM shows very detailed 3-dimensional images at much higher magnifications than is possible with a light microscope. The images created without light waves are rendered black and white.
 * Samples have to be prepared carefully to withstand the vacuum inside the microscope.
 * Biological specimens are dried in a special manner that prevents them from shriveling. Because the SEM illuminates them with electrons, they also have to be made to conduct electricity.
 * The way that makes mosquito sample conductive is that SEM samples are coated with a very thin layer of gold by a machine called a sputter coater.
 * The sample is placed inside the microscope's vacuum column through an air-tight door.
 * [[image:skematicworks.GIF width="376" height="561"]][[image:semoptic.gif width="376" height="547"]]


 * Sep 16, Tuesday**

Brief plan for Thursday -should be prepared for setting up the SEM sample on Thursday. -verify that the position is correct to remove the sample, remove it, and then attach samples of hair and wires of various thickness--perhaps with a bit of tape--across some gap on the current sample. -Before re-inserting, take images of the sample as best as I can -Then re-insert, update my logbook

Plus, today I'm going to try to find the SEM imgaes of human hair, or some wire, or whatsoever.

A | Scanning electron microscopy (SEM) image of the immature hair bundle of a mouse inner hair cell (apical turn of the cochlea, neonatal mouse). The nascent stereocilia are similar in appearance to the neighbouring microvilli. B | SEM image of mouse inner hair cell stereocilia during the final stage of stereocilia elongation (middle turn, postnatal day . C | Reorganization of the actin core during stereocilium maturation in chicks at various embryonic stages of development (indicated below the drawings). Actin filaments (red) migrate to the centre and form a hexagonal paracrystal (bottom row). Crosslinking of actin filaments (blue) increases with maturation and acquires transverse periodicity (upper row). Drawing is based on data reported by Tilney and DeRosier[|24]. D | Three models of the actin-core transformation from the microvillus to the stereocilium. a | Replacement of the whole actin-core structure by treadmilling. b | Growth of new actin filaments between existing ones. c | Migration of existing actin filaments to the centre of the core and the addition of new filaments to the periphery. For further details, see the main text.
 * SEM Images**






 * Sep 17, Wednesday**

Today, I'm going to try to find the images of certain wires. Fortunately, I was able to find some SEM images of hair. But for the future references or whatev, I wan to find various pictures of SEM. Hopefully, I could find many pictures and able to predict the result for better experiment.


















 * Sep 18, Thursday**

Today was the first day that I actually got to operate the SEM by myself. I was nervous at the first time, but it turned out to be okay :) First, I made a new specimen with the wire Dr.L gave to me, and my hair. I cut those into small size in that way the wire and my hair could fit in. Making a specimen was fun! The adversity of making specimen would be making things fit right into the size but I liked it. Anyway, after making a specimen, I read the manual over and got ready for running the SEM. I followed every step in manual and SEM seemed working great. I was VERY nervous ( not VERY, come to think of it, but I was..what should I say... I was excited and little bit worried at the same time. I was ambivalent a bit. But it was very interesting to operate the SEM.) When I the favorable environment was made to operate the SEM, I was starting to get ready to get some images. But the images did not come out... I don't know why.. So I asked for a help and we were trying to figure it out why we are not able to get images. He said the SEM is operating in right condition....... well,, yeah... we were trying to get an images for 15 mins controlling contrast, focus, and etc but we could not get any images. He said it might be the contrast problem. ...? I think I might have to try again on Monday. (hopefully, I could find why I was unable to get an image today.) Even though I could not get images of what I had expected, it was a good time that I can actually learn how to operate the SEM. Next time, I think I'll be more familiar with it! Anyway I have some pics that I took while operating the SEM and pics of specimen so I guess I'll update those tomorrow with some explanations. :) It's a great day!! Sun is out :)