Electron microscopes were once the turf of research laboratories that could foot the hefty bill of procuring and maintaining such equipment. But old models have been finding their way into the hands of eager individuals who are giving us an inside look at the rare equipment. Before you start scouring Craigslist, go on a crash course of what you need to know with Adam McComb’s Hacker’s Guide to Electron Microscopy. He presented the talk at the 2018 Hackaday Superconference and the recording was just published, you’ll find it below.
When you’re a high schooler who built a semiconductor fab in your garage, what’s next on your agenda? Why, adding a scanning electron microscope to your lab, naturally. How silly of you to ask.
When last we stumbled across the goings on in the most interesting garage in New Jersey, [Sam Zeloof] was giving a tour of his DIY semiconductor fabrication lab and showing off some of the devices he’s made there, including diodes and MOSFETs. As impressive as those components are, it’s the equipment he’s accumulated that really takes our breath away. So adding an eBay SEM to the mix only seems a natural progression, and a good reason to use some of the high vacuum gear he has. The video below shows [Sam] giving a tour of the 1990s-vintage instrument and shows images of various copper-sputtered samples, including a tick, which is apparently the state bird of New Jersey.
SEM hacks are by no means common around here, but they’re not unheard of. [Ben Krasnow] has used his to image cutting tools and phonograph records in action, and there are a few homebrew SEMs kicking around too. But our hats are off to [Sam] for yet another acquisition and a great tutorial to boot.
I used to have access to some pretty nice Scanning Electron Microscopes (a SEM) at my day job. While they are a bit more complex than a 3D printer, they are awfully handy when you need them. [Adam Guilmet] acquired a scrapped unit and started trying to figure out how to breathe life into it. His realization was that a SEM isn’t all that complicated by today’s standards. So he has set out to take what he has learned and build one from scrap.
In all fairness, he has a long way to go and is looking for help. He currently says, “[T]his is being powered by fairy dust, unicorn farts, and a budget that would make the poorest of students look like Donald Trump.” Still, he’s collected a lot of interesting data and we hope he can build a team that can succeed.
Last week on the Hacklet we covered optical microscopy projects. Those are the familiar scopes that many of us have at work or even at home on our benches. These are scopes that you typically can use with your eye, or an unmodified camera. This week we’re taking a look at more extreme ways of making small things look big. Electron streams and the forces of a single atom can be used to create incredibly magnified images. So let’s jump right in and check out the best advanced microscopy projects on Hackaday.io!
We start with [andreas.betz] and BluBEAM – a scanning laser microscope. [Andreas] aims to create a scanning confocal microscope. The diffraction limit is the law of the land for standard optical microscopes. While you can’t break the law, you can find ways around it. Confocal microscopy is one technique used quite a bit in medicine and industry. Confocal scopes are generally very expensive, well outside the budget of the average hacker. [Andreas] hopes to break that barrier by creating a scanning confocal microscope using parts from a PlayStation 3 Blu-Ray optical drive. Optical drives use voice coils to maintain focus. [Andreas] had to create a custom PCB with a voice coil driver to operate the PS3 optics assembly. He also needed to drive the laser. BluBeam is still very much a work in progress, so keep an eye on it!
Next up is [MatthiasR.] with DIY Scanning tunneling microscope. Open atmosphere scanning tunneling microscopes are popular on Hackaday.io. I covered [Dan Berard]’s creation in Hacklet 103. Inspired by Dan, [Matthias] is building his own STM.
Environmental vibration is a huge problem with high magnification microscopes. [Matthias] is combating this by building a vibration isolation platform using extruded aluminum. He’s currently working on the STM preamplifier, which amplifies and converts the nano amp STM values to voltages which can be read by a digital to analog converter. [Matthias] is using the venerable Analog ADA4530 for this task. With an input bias of 20 femtoamps (!) it should be up to the task.
Next we have [Jerry Biehler] AKA [macona] with Hitachi S-450 Scanning Electron Microscope. Scanning electron microscopes have to be the top of the microscopy food chain. Jerry got his hands on a 1980’s vintage Hitachi SEM which was no longer working. The problem turned out to be a dodgy repair made years earlier with electrical tape. Fast forward a couple of years of use, and [Jerry] has done quite a lot to his old machine. He’s learned how to make his own filaments from tungsten wire. The slow oil diffusion vacuum pump has been replaced with a turbomolecular pump. The SEM now resides in [Jerry’s] living room, which keeps it at a relatively constant temperature.
Finally, we have [beniroquai] with Holoscope – Superresolution Holographic Microscope. Holoscope is a device which increases the resolution of a standard camera by using the physical properties of light to its advantage. Precise tiny shifts of the object being magnified cause minute changes in a reflected image, which is captured by a Raspberry Pi camera. The Pi can then reconstruct a higher resolution image using the phase data. [beniroquai] has put a lot of time into this project, even sacrificing an expensive Sony connected camera to the ESD gods. I’m following along with this one. I can’t wait to see [beniroquai]’s first few images.
If you want to see more advanced microscopy projects, check out our new advanced microscope projects list! If I missed your project, don’t be shy, just drop me a message on Hackaday.io. That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!
When you’ve got a scanning electron microscope sitting around, you’re going to find ways to push the awesome envelope. [Ben Krasnow] is upping his SEM game with a new rig to improve image capture (video link) and more easily create animated GIFs and videos.
The color scheme of the SEM housing gives away its 80s vintage, and the height of image capture technology back then was a Polaroid camera mounted over the instrument’s CRT. No other video output was provided, so [Ben] dug into the blueprints and probed around till he found the high-resolution slow scan signal.
To make his Teensy-LC happy, he used a few op-amps to condition the analog signal for the greatest resolution and split out the digital sync signals, which he fed into the analog and digital ports respectively. [Ben] then goes into a great deal of useful detail on how he got the video data encoded and sent over USB for frame capture and GIF generation. Reading the ADC quickly without jitter and balancing data collection with transmission were tricky, but he has established a rock-solid system for it.
Hackaday Prize judge [Ben Krasnow] has been busy lately. He’s put his scanning electron microscope (SEM) to work creating an animation of a phonograph needle playing a record. (YouTube link) This is the same 80’s SEM [Ben] hacked back in November. Unfortunately, [Ben’s] JSM-T200 isn’t quite large enough to hold an entire 12″ LP, so he had to cut a small section of a record out. The vinyl mods weren’t done there though. SEMs need a conductive surface for imaging. Vinyl is an insulator. [Ben] dealt with this by using his vacuum chamber to evaporate a thin layer of silver on the vinyl.
Just imaging the record wouldn’t be enough; [Ben] wanted an animation of a needle traveling through the record grove. He tore apart an old phonograph needle and installed it in on a copper wire in the SEM. Thanks to the dual stage setup of the JSM-T200, [Ben] was able to move the record-chip and needle independently. He could then move the record underneath the needle as if it were actually playing. [Ben] used his oscilloscope to record 60 frames, each spaced 50 microns apart. He used octave to process the data, and wound up with the awesome GIF animation you see on the left.
[Ben] wasn’t done though. He checked out a few other recording formats, including CD and DVD optical media, and capacitance electronic disc, an obscure format from RCA which failed miserably in the market. The toughest challenge [Ben] faced was imaging the CD media. The familiar pits of a CD are stored on a thin aluminum layer sandwiched between the lacquer label and the plastic disc. He tried dissolving the plastic with chemicals, but enough plastic was left behind to distort the image. The solution turned out to be double-sided tape. Sticking some tape down on the CD and peeling it off cleanly removed the aluminum, and provided a sturdy substrate with which to mount the sample in the SEM.
We’re curious if stereo audio data can be extracted from the SEM images. [Oona] managed to do this with a mono recording from a toy robot. Who’s going to be the first one to break out the image analysis software and capture some audio from [Ben’s] images?
There are hackers who have soldering setups on the dining room table, and then there are hackers who have scanning electron microscopes in their living room. [Macona] is part of the latter group, with a Hitachi S-450 SEM he’s repaired and modified himself. [Macona] has documented the whole thing on Hackaday.io. The Hitachi came to him and a friend as a derelict. First it was broken, then stored for 10 years. It turned out the problem was a high voltage cable cut and spliced with electrical tape. The tape eventually broke down and shorted out the 500V supply. Thankfully the rectifier diodes were the only parts that needed to be replaced.
The SEM sprang to life and gave [Macona] and a friend their first images. However, SEMs are finicky beasts. Eventually the filament burned out and needed to be replaced. New filaments are $500 US for a box of 10, which is more than [Macona] wanted to spend. It turns out filaments can be built at home. A bit of .089mm tungsten wire and a spot welder were all it took to fix the issue. Next to go bad was the scan amplifier. While SEMs use many exotic parts, the Hitachi used relatively common Sanyo STK070 audio amplifiers for the purpose – an easy fix!
One thing that makes this SEM unique is the is Energy Dispersive X-Ray Spectroscopy (EDX) unit attached to it. The fragile liquid nitrogen cooled sensor was working, but the 1980’s era signal processing computer was a bit too old to bring up. A friend and fellow SEM hobbiest gave [Macona] a slightly newer Kevex Sigma Gold signal processor, which was nearly a plug and play upgrade for his machine. The new processor processor also gave him digital beam controls and a digital output which could be used to capture images with a PC.
Once all the connections were made, the EDX worked surprisingly well, even finding gold in a uranium ore sample placed in the microscope.
Now that old scanning electron microscopes being retired, it’s only a matter of time before more us get a chance to join the ranks of [Jeri Ellsworth], [Ben Krasnow] and [Macona] with our own personal SEMs!