afm
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afm [2021/03/24 11:59] mitchsenger [Step-by-step walk through for AC mode imaging] |
afm [2023/09/18 12:01] (current) dublin |
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| ===== Learning The AFM ===== | ===== Learning The AFM ===== | ||
| - | New users on the AFM are expected to get AFM training and then pass the {{::afm_training_quiz5.doc|AFM quiz}}. | + | For an overview, you should first, spend 5 minutes reading the [[http://en.wikipedia.org/wiki/Atomic_force_microscopy|Wikipedia article on AFM]]. |
| - | To find answers to some of the quiz questions, the "AFM Manualette" is a useful resource. | + | |
| + | A useful YouTube video ([[https://youtu.be/2Kv6KwADn7Q?t=177|I made a giant atomic force microscope]]) shows a giant AFM to explains how the tip-cantilever-surface interact with each other, and how the image is acquired. | ||
| + | |||
| + | Training involves | ||
| + | - A session where you watch an experienced user (and ask questions) | ||
| + | - Reading the "AFM Manualette". | ||
| + | - A session where you "fly the AFM" with an experienced co-pilot talking you through each step. | ||
| + | - Take a written test to check that you understand the important concepts: {{::afm_training_quiz5.doc|AFM quiz}}. | ||
| + | - A session where you "fly the AFM" with an experienced co-pilot watching you. You can follow your own written notes, or use the "step-by-step walk through" that is provided below. This final supervised session should include changing a tip. (Use an old tip first for practice). | ||
| + | |||
| + | The "AFM Manualette" is located in two places: | ||
| *T:drive/Minot Group/Group documents/Manuals and documentation/AFM/MFP-3D Manualette_v9.pdf | *T:drive/Minot Group/Group documents/Manuals and documentation/AFM/MFP-3D Manualette_v9.pdf | ||
| + | *Box folder "Minot Group Documents" | ||
| - | First, spend 5 minutes reading the [[http://en.wikipedia.org/wiki/Atomic_force_microscopy|Wikipedia article on AFM]]. | + | With the AFM Manualette, there are some useful concept videos. I recommend watching The movies "Amplitude Feedback" and "Cantilever SEM". There is also a comprehensive manual (Ver_04_08). I recommend reading chapter 5. |
| - | Second, watch a couple of the 30 second intro videos: T:\Physics\Minot Group\Group documents\Manuals\AFM\Asylum Movies. The movies "Amplitude Feedback" and "Cantilever SEM" will help you visualize the instrument. You must understand basic questions like | + | You must understand basic questions like |
| *how does the sample move in the x-y plane? | *how does the sample move in the x-y plane? | ||
| *how is the tip deflection measured? | *how is the tip deflection measured? | ||
| Line 42: | Line 53: | ||
| *what does the feedback circuit do? | *what does the feedback circuit do? | ||
| - | Third, get a comprehensive overview of how the system works by reading Chapter 5 of the manual | + | We use ac-mode imaging. So, it’s important to understand the basic idea of shaking a cantilever at its base to excite the first vibrational mode (the system achieves 100-nanometer-amplitude motion at the free-end of the cantilever, by shaking the base of the cantilever by a fraction of a nanometer) |
| - | T:\Physics\Minot Group\Group documents\Manuals\AFM\Manual Ver_04_08.pdf | + | [[https://www.youtube.com/watch?v=AA6gWHu7GRs&ab_channel=SLURocketry]] |
| - | + | ||
| - | Fourth, spend some time watching an experienced person use it. Several aspects of the AFM require experience and dexterity: | + | |
| - | *lifting the heavy head off the stage and flipping it over | + | |
| - | *using a pair of tweezer to change the AFM tip. | + | |
| - | The only way to learn this dexterity is careful instruction from an experienced user. | + | |
| - | + | ||
| - | Then you are ready for a supervised training session where you operate the instrument on your own. There is a red binder with some procedural information (the "manualette") which will help you with everyday operational questions. There is also a brief standard operating procedure on this wiki page (it will not make much sense unless you've already been introduced to the instrument). A pdf copy of the manualette is available on the T:Drive (T:\Physics\Minot Group\Manuals\MFP-3D Manualette Beta v10.pdf). | + | |
| - | + | ||
| - | The last step is to pass the {{::afm_training_quiz5.doc|AFM quiz}}. | + | |
| Line 59: | Line 61: | ||
| - Sign into the black notebook (on the table next to the AFM) | - Sign into the black notebook (on the table next to the AFM) | ||
| - Open version 16 of the AFM software (not version 14). It is critical that you use the correct version (switching between older/newer versions can corrupt the x-y stage calibration, which causes violent shaking of the x-y stage when the user starts scanning). A copy of a V16 AFM control Igor experiment is in the local Public documents folder. | - Open version 16 of the AFM software (not version 14). It is critical that you use the correct version (switching between older/newer versions can corrupt the x-y stage calibration, which causes violent shaking of the x-y stage when the user starts scanning). A copy of a V16 AFM control Igor experiment is in the local Public documents folder. | ||
| - | - Place the sample to be imaged on the tray. | + | - Click the first option, "Template" |
| + | - Once software loads, set AC mode in master panel | ||
| + | - Place the sample to be imaged on the tray. Make sure that the stage x-y control thumbscrews are centered. | ||
| - Make sure the vibration isolation stage is on and isolation is enabled. | - Make sure the vibration isolation stage is on and isolation is enabled. | ||
| - | - Raise the legs on the MFP-3D tripod to ensure the tip does not smash into the sample. | + | - Raise the legs on the MFP-3D tripod by ~5 turns to ensure the tip does not smash into the sample. |
| - Set the MFP-3D over sample | - Set the MFP-3D over sample | ||
| - Align Laser: | - Align Laser: | ||
| - | * Turn on the camera - Click the lower left icon with a picture of a TV on it | + | * Turn on the camera - Click the lower left icon with a picture of a camera on it |
| * Turn on the camera light - Switch on the box which sits on top of the AFM | * Turn on the camera light - Switch on the box which sits on top of the AFM | ||
| * Align camera on cantilever - Two knobs sticking up at the very rear of the MFP-3D | * Align camera on cantilever - Two knobs sticking up at the very rear of the MFP-3D | ||
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| - X Set AC Mode - In main tab of the master panel select 'AC Mode' in the 'Imaging Mode' pull down menu | - X Set AC Mode - In main tab of the master panel select 'AC Mode' in the 'Imaging Mode' pull down menu | ||
| - Tune the AFM | - Tune the AFM | ||
| - | * X Open 'Tune' tab in the master panel | + | * Open 'Tune' tab in the master panel |
| - | * X Set 'Target %' to -5.0 % (this setting favors repulsive mode imaging, often recommended for beginners) | + | * Set 'Target %' to -5.0 % (this setting favors repulsive mode imaging, often recommended for beginners) |
| - | * Click the 'Auto Tune' button | + | * Click the 'Auto Tune' button and wait for tuning to finish. Software will set drive frequency. |
| - | * X Click the peak of the newly displayed resonance peak and set it as the max amplitude | + | |
| - Engage the tip | - Engage the tip | ||
| - | * X Set the I gain to 10 | + | * Set the I gain to 10 |
| - | * Make the 'Set Point Voltage' about 95% of the orignal amplitude | + | * Make the 'Set Point Voltage' about 95% of the target amplitude (1 V by default) |
| * Click 'engage' in the S&D meter and | * Click 'engage' in the S&D meter and | ||
| - | * Lower the tip (tripod thumbwheel) while watching the amplitude. The amplitude will drop as you near the surface. The computer will beep when feedback kicks in to stop the amplitdue from droping below the setpoint. Continue lowering until the Z voltage is in the middle of its range. | + | * Lower the tip (tripod thumbwheel — left = up, right = down) while watching the amplitude. The amplitude will drop as you near the surface. The computer will beep when feedback kicks in to stop the amplitude from dropping below the setpoint. Continue lowering until the Z voltage is in the middle of its range. |
| + | * If the Z-voltage goes down instead of up, re-tune. If that doesn't fix it, you might have junk stuck to the tip. | ||
| * Lower the 'Set Point Voltage' by about 10%. | * Lower the 'Set Point Voltage' by about 10%. | ||
| * Lower the tip until the 'Z voltage' approximately in the middle of its range. | * Lower the tip until the 'Z voltage' approximately in the middle of its range. | ||
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| - Manually retract tip from sample - Give the front thumbwheel a few clockwise twists | - Manually retract tip from sample - Give the front thumbwheel a few clockwise twists | ||
| - Turn off laser - Key on the AFM computer | - Turn off laser - Key on the AFM computer | ||
| - | - Turn off camera - Close camera window | ||
| - Turn off camera light - Switch on the box sitting on top of the AFM | - Turn off camera light - Switch on the box sitting on top of the AFM | ||
| - | - Place MFP-3D onto it's shelf holder | + | - Place MFP-3D onto its shelf holder |
| - Remove sample | - Remove sample | ||
| + | - Close software and log out | ||
| - Leave controller and PC running unless expecting a power outage | - Leave controller and PC running unless expecting a power outage | ||
| ===== Imaging rules of thumb ===== | ===== Imaging rules of thumb ===== | ||
| Line 107: | Line 111: | ||
| **Beginner settings** | **Beginner settings** | ||
| *Scan size 1 micron | *Scan size 1 micron | ||
| - | *Scan rate 1 Hz | + | *Scan rate < 15 micron / s |
| *Integral gain 10 | *Integral gain 10 | ||
| *Free amplitude 1 V (~ 100 nm) | *Free amplitude 1 V (~ 100 nm) | ||
| Line 223: | Line 227: | ||
| For more specialized image analysis try [[http://rsbweb.nih.gov/ij/docs/index.html|ImageJ]]. ImageJ is a free software from the National Institutes of Health (NIH). It is a useful tool for doing complex image analysis tasks, such as [[http://rsbweb.nih.gov/ij/docs/index.htmlhttp://rsbweb.nih.gov/ij/docs/examples/dna-contours/index.html|measuring the length of wiggly CNTs or DNA]], or [[http://rsbweb.nih.gov/ij/docs/index.htmlhttp://rsbweb.nih.gov/ij/docs/examples/dna-contours/index.htmlhttp://rsbweb.nih.gov/ij/docs/pdfs/examples.pdf|measuring particle sizes and outputting size distributions]]. | For more specialized image analysis try [[http://rsbweb.nih.gov/ij/docs/index.html|ImageJ]]. ImageJ is a free software from the National Institutes of Health (NIH). It is a useful tool for doing complex image analysis tasks, such as [[http://rsbweb.nih.gov/ij/docs/index.htmlhttp://rsbweb.nih.gov/ij/docs/examples/dna-contours/index.html|measuring the length of wiggly CNTs or DNA]], or [[http://rsbweb.nih.gov/ij/docs/index.htmlhttp://rsbweb.nih.gov/ij/docs/examples/dna-contours/index.htmlhttp://rsbweb.nih.gov/ij/docs/pdfs/examples.pdf|measuring particle sizes and outputting size distributions]]. | ||
| + | |||
| + | [[http://gwyddion.net/|Gwyddion]] is another free software designed for analyzing scanning microscope probe images. It is intuitive and has many features to improve image quality. Carly has found it useful for looking at images of graphene. | ||
| ===== Supplies ===== | ===== Supplies ===== | ||
afm.1616612387.txt.gz · Last modified: 2021/03/24 11:59 by mitchsenger
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