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projects:stm [2025/08/07 22:13] – [STM key information] rahixprojects:stm [2025/08/07 22:21] (current) – [STM key information] rahix
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 ==== STM key information ==== ==== STM key information ====
  
-=== Mechanics ===+=== STM Scanning Head === 
 +The scanning head of our STM uses 3 piezo actuators oriented along the 3 cartesian axes.  We currently do not have data on their actuation range.
  
-== STM Mount ==+The tip is made from tungsten wire and mounted to the scanning head using a screw terminal.
  
 +To be documented.
 +
 +=== STM Mount ===
 The STM mount consists of two aluminum plates which seat against each other precisely using a [[http://www.g2-engineering.com/technology-kinematics|kinematic mount]] made from 3 micrometer screws. The STM mount consists of two aluminum plates which seat against each other precisely using a [[http://www.g2-engineering.com/technology-kinematics|kinematic mount]] made from 3 micrometer screws.
  
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   * Back is hence 0.0125mm per revolution or 12.5µm    * Back is hence 0.0125mm per revolution or 12.5µm 
  
-== Vibration isolation ==+=== Electronics === 
 +The control loop for running the STM in constant current mode is currently an entirely analog design.  There is a transimpedance amplifier which preamplifies the tunneling current with a gain of 10⁹ V/A.  This nicely maps pA to mV (and measured tunneling currents are in the hundreds of pA range). 
 + 
 +Learn more about the electronics here: [[https://git.fa-fo.de/fafo/k8ik-stm/src/branch/main/Electronics]] 
 + 
 +=== Vibration Isolation ===
  
 We have built ourselves a simple passive vibration isolation using tension springs and a large mass.  The intended damping element (an eddy current brake) did not end up working, but also wasn't really needed after all. We have built ourselves a simple passive vibration isolation using tension springs and a large mass.  The intended damping element (an eddy current brake) did not end up working, but also wasn't really needed after all.
  
-{{:projects:stm-frame-cad.png?400|}}+{{:projects:stm-frame-cad.png?600|}}
  
 We have not measured performance, but the real world resonance frequency matches the calculations quite well. Here is the calculated transmissibility (blue curve): We have not measured performance, but the real world resonance frequency matches the calculations quite well. Here is the calculated transmissibility (blue curve):
  
 {{:projects:stm:dampening-2025-06-08.png?400|}} {{:projects:stm:dampening-2025-06-08.png?400|}}
- 
-=== Electronics === 
-Learn more about the electronics here: [[https://git.fa-fo.de/fafo/k8ik-stm/src/branch/main/Electronics]] 
- 
-== Piezos == 
- 
- 
 ==== Other Projects ==== ==== Other Projects ====
 There are quite a few other DIY/open STM builds out there.  Here are a few links for further reading: There are quite a few other DIY/open STM builds out there.  Here are a few links for further reading: