Putting Lightning In Acrylic

Some folks at the i3Detroit hackerspace had an opportunity come up that would allow them to capture lightning in acrylic. They created a few Lichtenberg figures thanks to the help of a plastic tubing manufacturer, some lead sheet and a bunch of 1/2″ thick acrylic.

Lichtenberg figures are the 3D electrical trees found in paperweights the world over. They’re created through electrical discharge through an insulator, with lightning being the most impressive Lichtenberg figure anyone has ever seen. These figures can be formed in smaller objet d’art, the only necessity being a huge quantity of electrons pumped into the insulator.

This was found at Mercury Plastics’ Neo-Beam facility, a 5MeV electron accelerator that’s usually used to deliver energy for molecular cross linking in PEX tubing to enhance chemical resistance. For one day, some of the folks at i3Detroit were able to take over the line, shuffling a thousand or so acrylic parts through the machine to create Lichtenberg figures.

When the acrylic goes through the electron accelerator, they’re loaded up with a charge trapped inside. A quick mechanical shock discharges the acrylic, creating beautiful tree-like figures embedded in the plastic. There are a lot of pictures of the finished figures in a gallery, but if you want to see something really cool, a lead-shielded GoPro was also run through the electron accelerator. You can check out that video below.

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Electron Beam Control In A Scanning Electron Microscope

Electron

A few years ago [Ben Krasnow] built a scanning electron microscope from a few parts he had sitting around. He’s done a few overviews of how he built his SEM, but now he’s put up a great video on how to control electrons, focus them into a point, and scan a sample.

The basic idea behind a scanning electron microscope is to shoot electrons down a tube, focus them into a point, and scan a conductive sample and detect the secondary electrons shot off the sample and display them on an oscilloscope. [Ben] is generating electrons with a small tungsten filament at the top of his electron ‘stack’. Being like charged, these electrons naturally fan out, so a good bit of electron optics are required to get a small point.

Focusing is done through a series of pinholes and electrostatic deflectors, much like you’d see in an old oscilloscope CRT. In the video, you can see [Ben] shooting electrons and displaying a Christmas tree graphic  onto a piece of phosphor-coated glass. He has a pretty big scanning area in his SEM, more than enough to look at a few chips, wafers, and whatever other crazy stuff is coming out of [Ben]’s lab.

Video below, along with the three-year-old overview of the entire microscope.

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Open Source STM

We hope you paid attention in advanced theoretical and quantum physics classes, or making your own Open Source Scanning-Tunneling Microscope might be a bit of a doozy. We’re not even going to try to begin to explain the device (honestly we slept through that course) beyond clarifying it is used for examining the molecular and atomic structure of surfaces; but for those still interested there is a nice breakdown of how Scanning Tunneling Microscopy works.

[Thanks Rich]