[TriEmbed] Reminder & Discord link Re: Join us July 1st to learn about a new Scanning tunneling microscope project

[Pete soper]

The meeting is 7pm via a zoom-like thing in your browser here: 
https://meet.jit.si/TriEmbed

The Discord server mentioned earlier can be joined here:

https://discord.gg/7NUxwzKc

(Discord is not being used directly for the meeting)

On 6/27/24 20:49, Pete Soper wrote:
>
> Folks,
>
>    Nick Edgington started a project with the Forge Initiative to build 
> an affordable scanning tunneling microscope ("STM") capable of 
> visualizing individual atoms. He,  Jaime Johnsen, and I have been 
> gathering up information and doing a few initial things to test the 
> waters with input from Rob Mackey of the Forge and others.  Now we'd 
> like to start organizing the project and connecting with folks 
> interested in becoming involved.
>
>    An STM is a primarily electronic device that senses quantum 
> tunneling current flows between individual atoms while an electrically 
> charged, atomically sharp probe moves at very close range across the 
> surface to be scanned. Commercial STMs such as at universities are 
> very expensive. Our goal is to make something that can be reproduced 
> for a few hundred dollars. Ultimately we want a kit suitable for 
> school children. More details of STM operation here: 
> https://my.eng.utah.edu/~lzang/images/Lecture_6_STM.pdf
>
>   Here are some key features of the project:
>
>   * Extremely efficient resistance to vibration. Because the probe
>     must move less  than a nanometer from the surface to be scanned,
>     very efficient dampening must be used. Also the dampening must be
>     portable and use inexpensive materials.
>   * A means of moving the probe very precisely. Piezo crystals and
>     precise applied voltages are the common method for hobby STMs.
>   * A means of creating atomically sharp probe wires (the tip must be
>     a single atom!). This typically involves electrochemical etching
>     with gizmos to manage the process in a very repeatable manner.
>     Alternatively, a probe tip can be made in a much simpler way with
>     manual techniques for cutting the probe wire.
>   * A very stable package for the probe that contains the piezo probe
>     actuator and the probe current front end electronics. One of the
>     best projects we've found uses what appears to be a CNC-machined
>     block of aluminum that is a thing of beauty just asking to be used
>     for inspiration.
>   * High performance but inexpensive electronics to sense probe
>     current (*peak* current is a nanoampere or two) and digitize it,
>     arrange bias voltages between tip and target to enable quantum
>     tunneling, and move the probe on three axes. The power supplies
>     have to be excellent. Custom PC boards are a given.
>   * Software to control the system, gather data and translate it into
>     visualization and provide a user interface. A large body of code
>     for the Espressif ESP32 (project Edger) can be leveraged for a
>     very low cost system. The software will probably be a mixture of
>     Python, C, and Javascript.
>   * Making test systems that help detect things going right and wrong.
>   * Many supporting tasks to do with documentation, safety,
>     communication, coordination, sponsorship, etc.
>
> *An informal meeting will be held this Monday July 1st at 7pm *with 
> Jitsi using the usual TriEmbed URL : https://meet.jit.si/TriEmbed .
>
> *A more formal meeting will be held in mid August* in a room provided 
> by the town of Apex (the Forge is based in Apex).
>
>   The various subsystems of an STM really push the envelope for 
> performance, and this project will be quite challenging, even though 
> there are many shoulders to stand on.
>
>   A Discord channel on the Edger project is accumulating records while 
> we finish setting up a GitHub repository and supporting web resources. 
> I'll send directions on how to hook up with it later.
>
> Pete
>
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