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projects:stm:log [2025/09/07 22:42] – [Day 2025-09-07 (rahix, q3k, hugo)] rahixprojects:stm:log [2026/07/04 16:33] (current) – disclaimer rahix
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 ====== Lab Notes for the Scanning Tunneling Microscope ====== ====== Lab Notes for the Scanning Tunneling Microscope ======
 +These are the lab notes for the STM.  See the [[projects:stm:start|STM Project Page]] for an overview of the project.
  
 +> //This page is a lab notebook. It documents the work done in the lab and our thoughts, theories, and findings related to it. Everything you read here is work in progress and not final results. We believe it is best to have our lab notes out in the open, because it gives more detailed insight into what worked for us and what didn't. Of course you can also use this page to follow our progress!//
 +==== Day 2026-01-11 (k8ik, rahix) ====
 +Currently, work is focused on setting up a precise interferometer which we can use to characterize movement of the STM stage.
 +
 +Progress is documented here: [[projects:optics:log|Lab Notes for Optics Experiments]]
 +==== Day 2025-09-20 (rahix) ====
 +Modelled more of the as-built of the current STM setup in mechanical CAD so we have a reference model:
 +
 +{{:projects:stm:cad-stm.png?900|}}
 ==== Day 2025-09-07 (rahix) ==== ==== Day 2025-09-07 (rahix) ====
-Took the video capture from yesterday, of the beam bouncing from the STM off a mirror 2.35m away and back to the camera on the STM and ran some analysis on the data.  The notebook is+Took the video capture from yesterday, of the beam bouncing from the STM off a mirror 2.35m away and back to the camera on the STM and ran some analysis on the data. 
 + 
 +Analysis works like this:  For each frame, we find the beam center.  Then we look at the spectral content of the displacement in X and Y directions.  Check the full notebook for details: ''Laser-Wobble.ipynb'' from [[https://git.fa-fo.de/fafo/k8ik-stm/src/branch/main/Calculations|Calculations/]] ([[https://git.fa-fo.de/fafo/k8ik-stm/src/branch/main/Calculations/rendered/Laser-Wobble.md|Rendered Notebook]]). 
 + 
 +Here is the final figure: 
 + 
 +{{:projects:stm:2025-08-07-vibration-spectral-density.png?900|}}
  
-Analysis works like this:  For each frame, we find the beam center.  Then we look at the spectral content of the displacement in X and Y directions.+The most interesting result is the peak highlighted by the red line.  The red line marks the theoretical resonance frequency of the vibration isolation system that we had calculated in the past.  Seeing a peak right at this frequency sparks a lot of confidence!
  
 +The results are limited up the 15 Hz because of the 30 fps video capture.  But towards the right of the figure, the data becomes pretty meaningless anyway as the displacements are too small for the camera to pick up already.
 ==== Day 2025-09-06 (rahix, q3k, hugo) ==== ==== Day 2025-09-06 (rahix, q3k, hugo) ====
 Rebuilt the entire experiment to clean up the space and install some shelving.  All connections are remade but the setup has not been reverified to tunneling. Rebuilt the entire experiment to clean up the space and install some shelving.  All connections are remade but the setup has not been reverified to tunneling.
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 Played a bit more with the [[https://git.fa-fo.de/fafo/k8ik-stm/src/branch/main/Calculations/Spring-Dimensioning.ipynb|calculations for the mass-spring-damper system]] to see where we are at, comparing to commercially available systems: Played a bit more with the [[https://git.fa-fo.de/fafo/k8ik-stm/src/branch/main/Calculations/Spring-Dimensioning.ipynb|calculations for the mass-spring-damper system]] to see where we are at, comparing to commercially available systems:
  
-{{:projects:stm:dampening-2025-06-08.png?nolink&400|}}+{{:projects:stm:dampening-2025-06-08.png?400|}}
  
  
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 Calculated the damping behavior of our setup: Calculated the damping behavior of our setup:
  
-{{:projects:stm:damping-ratio-2025-06-08.png?nolink&400|}}+{{:projects:stm:damping-ratio-2025-06-08.png?400|}}
  
 EMI Box: EMI Box:
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 Removed the formwork from the conrete block we poured on friday.  The block is so nice! Removed the formwork from the conrete block we poured on friday.  The block is so nice!
  
-{{:projects:stm:stm-concrete-weight.jpg?nolink&400|}}+{{:projects:stm:stm-concrete-weight.jpg?400|}}
  
   * Lessons learned:   * Lessons learned:
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 Poured a concrete weight for the vibration isolation system: Poured a concrete weight for the vibration isolation system:
  
-{{:projects:stm:concrete-pouring.jpg?nolink&400|}}+{{:projects:stm:concrete-pouring.jpg?400|}}
  
   * Lessons learned:   * Lessons learned: