See the Radioactive World with This Peltier Cloud Chamber

Remember when a homemade cloud chamber was a science fair staple? We haven’t participated for decades, but it seemed like every year someone would put a hunk of dry ice in a fish tank, add a little alcohol, and with the lighting just right – which it never was in the gymnasium – you might be lucky enough to see a few contrails in the supersaturated vapor as the occasional stray bit of background radiation whizzed through the apparatus.

Done right, the classic cloud chamber is a great demonstration, but stocking enough dry ice to keep the fun going is a bit of a drag. That’s where this Peltier-cooled cloud chamber comes into its own. [mosivers] spares no expense at making a more permanent, turn-key cloud chamber, which is perched atop a laser-cut acrylic case. Inside that is an ATX power supply which runs a Peltier thermoelectric cooling module. Coupled with a CPU cooler, the TEC is able to drive the chamber temperature down to a chilly -42°C, with a strip of white LEDs providing the required side-lighting. The video below gives a tour of the machine and shows a few traces from a chunk of pitchblende; it’s all pretty tame until [mosivers] turns on his special modification – a high-voltage grid powered by a scrapped electronic fly swatter. That really kicks up the action, and even lets thoriated TIG welding electrodes be used as a decent source of alpha particles.

It’s been a while since we’ve seen a Peltier cloud chamber build around here, which is too bad because they’re great tools for engaging young minds as well as for discovery. And if you use one right, it just might make you as famous as your mother.

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The Electronics of Cold War Nightmares

It is a good bet that if you look around you, you’ll be able to find at least one smoke detector in sight. If not, there’s probably one not too far away. Why not? Fires happen and you’d like to know about a fire even if you are sleeping or alert others if you are away. During the cold war, there were other things that people didn’t want to sleep through. [Msylvain59] tears down two examples: a Soviet GSP-11 nerve agent detector and a Polish RS-70 radiation alarm. You can see both videos, below.

In all fairness, the GSP-11 is clearly not meant for consumer use. It actually uses a test strip that changes colors and monitors the color change. Presumably, the people operating it were wearing breathing gear because the machine could take quite a while to provide a positive output. Inside reminded us of a film processing machine, which isn’t too far off.

The radiation monitor looks more like a miniature version of an old floor-standing radio. The case design, the thick-traced, single-sided, hand-drawn printed wiring board, and the –by today’s standards — huge parts within all contribute to making this look like a piece of radio gear from the 1970s or even earlier.

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Solar Power For Chernobyl’s Second Generation of Electricity

When featuring cool hacks repurposing one thing for something else, we prefer to focus on what we could get our hands on and replicate for ourselves. Not this one, though, as nobody else has the misfortune of being responsible for 2,000 square kilometers (772 square miles) of radioactive contaminated land like the government of Ukraine. Trying to make the best of what they have, they’ve just launched a pilot program working to put up solar power farms inside the Chernobyl Exclusion Zone.

This is sure to invite some jokes in the comments section, but the idea has merit. Thirty years of weather has eroded the worst aftermath of the Chernobyl explosion. That area is no longer immediately lethal and people have been making short visits. Spanning from safety inspectors, to scientists, to curious adventurers with questionable judgement making television shows. Supposedly, by following rules on what not to do, it’s possible to keep radiation exposure of a short visit down to the level experienced by frequent fliers. But that’s still too much radiation for long-term stay. That means no homes, office parks, or factories. No agriculture either, as plants and animals grown in the area should not be eaten.

So what’s left? That’s what Ukraine has been struggling with, as it tried to figure out something positive to offset the headaches of monitoring the area.

Well, next to the defunct power plant is the electric distribution infrastructure it used to feed into, and photovoltaic power generation requires little human oversight. Some maintenance will be required, but hopefully someone has worked out how to keep maintenance workers’ cumulative exposure to a minimum. And if this idea pans out, clean renewable energy would start flowing from the site of one of the worst ecological disasters of our era. That makes it a worthwhile hack on a grand scale.

[via Gizmodo]

A Vacuum Tube and Barbecue Lighter X-Ray Generator

A certain subset of readers will remember a time when common knowledge held that sitting too close to the TV put you in mortal peril. We were warned to stay at least six feet back to avoid the X-rays supposedly pouring forth from the screen. Nobody but our moms believed it, so there we sat, transfixed and mere inches from the Radiation King, working on our tans as we caught up on the latest cartoons. We all grew up mostly OK, so it must have been a hoax.

Or was it? It turns out that getting X-rays from vacuum tubes is possible, at least if this barbecue lighter turned X-ray machine is legit. [GH] built it after playing with some 6J1 rectifier tubes and a 20-kV power supply yanked from an old TV, specifically to generate X-rays. It turned out that applying current between the filament and the plate made a Geiger counter click, so to simplify the build, the big power supply was replaced with the piezoelectric guts from a lighter. That worked too, but not for long — the tube was acting as a capacitor, storing up charge each time the trigger on the lighter was pulled, eventually discharging through and destroying the crystal. A high-voltage diode from a microwave oven in series with the crystal as a snubber fixed the problem, and now X-rays are as easy as lighting a grill.

We have to say we’re a wee bit skeptical here, and would love to see a video of a test. But the principle is sound, and if it works it’d be a great way to test all those homebrew Geiger counters we’ve featured, like this tiny battery-powered one, or this one based on the venerable 555 timer chip.

Harvesting Energy from the Earth with Quantum Tunneling

More energy hits the earth in sunlight every day than humanity could use in about 16,000 years or so, but that hasn’t stopped us from trying to tap into other sources of energy too. One source that shows promise is geothermal, but these methods have been hindered by large startup costs and other engineering challenges. A new way to tap into this energy source has been found however, which relies on capturing the infrared radiation that the Earth continuously gives off rather than digging large holes and using heat exchangers.

This energy is the thermal radiation that virtually everything gives off in some form or another. The challenge in harvesting this energy is that since the energy is in the infrared range, exceptionally tiny antennas are needed which will resonate at that frequency. It isn’t just fancy antennas, either; a new type of diode had to be manufactured which uses quantum tunneling to convert the energy into DC electricity.

While the scientists involved in this new concept point out that this is just a prototype at this point, it shows promise and could be a game-changer since it would allow clean energy to be harvested whenever needed, and wouldn’t rely on the prevailing weather. While many clean-energy-promising projects often seem like pipe dreams, we can’t say it’s the most unlikely candidate for future widespread adoption we’ve ever seen.

The Physics of Healing: Radiation Therapy

Few days are worse than a day when you hear the words, “I’m sorry, you have cancer.” Fear of the unknown, fear of pain, and fear of death all attend the moment when you learn the news, and nothing can prepare you for the shock of learning that your body has betrayed you. It can be difficult to know there’s something growing inside you that shouldn’t be there, and the urge to get it out can be overwhelming.

Sometimes there are surgical options, other times not. But eradicating the tumor is not always the job of a surgeon. Up to 60% of cancer patients will be candidates for some sort of radiation therapy, often in concert with surgery and chemotherapy. Radiation therapy can be confusing to some people — after all, doesn’t radiation cause cancer? But modern radiation therapy is a remarkably precise process that can selectively kill tumor cells while leaving normal tissue unharmed, and the machines we’ve built to accomplish the job are fascinating tools that combine biology and engineering to help people deal with a dreaded diagnosis.

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Hackaday Prize Entry: An Open Radiation Detector

For his Hackaday Prize entry, [Carlos] is pushing the boundaries of what can be built with PCBs. He’s designed a very low-cost radiation detector that leverages pick and place machines, off-the-shelf components, and very simple electronics. It’s a novel ion chamber design, and if you ever needed a low-cost, easily manufacturable radiation detector, this is the project you want.

Instead of a Geiger tube or a spark detectors, this radiation detector uses an ionization chamber to detect radiation. This project was inspired by the work of [Charles Wenzel] and [Alan Yates], and the implementation is actually pretty simple. A metal can — or some other type of enclosure — is electrified, and a single wire is stuck right into the middle of the can. When alpha and beta particles enter the can, air molecules are ionized, and attracted to either the can or the wire by a difference in voltage. A tiny bit of current flows between the can and the wire, which can be detected if you have a sufficiently sensitive circuit.

The basic idea is well-publicised and well-understood. What [Carlos] is doing with this project is making an ionization chamber easily manufacturable. He’s doing this entirely with standard PCBs and solder instead of paint cans, RF connectors, and deadbugged transistors of the earlier experiments. The resulting PCB actually looks like something that wasn’t put together in a garage (even though it probably was), and is an amazing entry for the Hackaday Prize.