See Atomic Particles With Your Own Eyes Part 4: Inferrence via Ion Induced Voltage Fluctuations (Welcome to the Ion Chamber)

So You Wanna See Atomic Particles With Your Own Eyes Part 4: Inferrence via Ion Induced Voltage Fluctuations (Welcome to the Ion Chamber)

There is more to seeing than what meets the eyeball.

-N.R. Hanson, Patterns of Discovery

We've explored actually seeing the paths of particles in a nuclear cloud chamber; watched corruscating alpha particles slam against a phosphor screen in spinthariscope; watched them explode when crossing the high voltage spark detector; found fields of activity with the radio telescope; and just horsed around with regular old Geiger Counters for fun. 

It's time to mix low voltage (8.5v) with soldering, multimeters and aluminum foil to make an Ion Chamber.

Simply put: we charge a cookie tin and have a wire inside that acts as a cathode. As ionized particles enter the chamber they create a current flow that is displayed on a multimeter. The higher the volts, the more ions which means greater radiation. 

Cookie tin. 

Screws that join the circuit board physically and electricity to the tin.

The cover of the tin becomes a circuit board cover.

I soldered a wire to the middle post of a Darlington transistor.  This is the cathode that passes through the bottom of the circuit board and into the tin. The Darlington transistor is actually two transistors in one package. The first part amplifies the incoming current, the second amplifies it even more!

A guy named Sid Darlington actually patented the idea of putting "two or three" components into a single unit back in the early 1950s. Not sure how momentous this was. Um, "let's moosh together two pizzas and make a mediocre double-pizza with a soggy crust center." Yeah, no! I think he actually figured out how to do it though, so it wasn't just the dopey idea of smashing them together that was his claim to fame.

Anyway, it acts like a single transistor but it amps up (high gain) the input. However the first of the Darlington ‘pair’ sucks up the voltage and responds in the circuit, leaving the second built in transistor a little ‘hungry’ for more. 

Think of it like two cats in a single cage: first one gets enough food, the second doesn’t so it makes for a really jittery pair of cats. That’s generally bad, but how can we use this to our advantage? 

Darlington Pairs are very jittery = very sensitive! They make create components in touch sensors. What are we doing? Well, we’re building a sensor that detects when it is touched by tiny little ions right? Great! How can we increase the jittery sensitivity of this? By adding that long wire to the middle leg of the Darlington transistor and extending it into your ion chamber. Neato!

Here's a photo of the wire coming off the Darlington straight at the camera.

By the way, I ordered the circuit board and transistor from Madscientisthut.com. They're neat people, ship fast and have cool stuff. You can order an ion chamber kit from them in various ways. In one of the kits they'll even through in a multimeter!! Or you can buy the board and source the parts separately from Radio Shack or wherever. I've found that usually on Amazon you have to buy 100 of the same components-it's cheap, but do I need 100 Darlington Transistors for $5 and free shipping? No, that's where kit designers like Madscientisthut.com come in and make everything easier.

I do order capacitors in bulk, because I get weird and blow lots of capacitors. A just received a bag of 100 capacitors from Amazon, which was a good deal and convenient...as you'll see in my next post about linear laboratory bench power supply making (there will be a loud bang and a little smoke!). 




Ok, here is the circuit board mounted on the cookie tin.

The inside of the cookie tin with the cathode wire in place.

The open end of the tin is covered with aluminum foil. I roughly zeroed out the meter.

Here is that meter during testing with a uranium test source (upper left above the foil).

Back view of the unit with the circuit board guard off and meter reading 15.1 mV. Notice the vial with uranium placed behind the ion chamber.

I moved the uranium to the front (sensing) side of the chamber. Notice the meter has started climbing.

Here's a nifty video I made of it in action. All of this was done before I properly mounted the circuit board deflector guard.

With the circuit board guard professionally mounted (with two different kinds of tape) I can now turn the unit on and use a plastic screw driver to zero in the unit by adjusting a 10k and  a 100k potentiometer through the holes.

Not something I'd have in my carry on luggage, but it works and only took me two nights to build.

The first night I was soldering and half my house went dark. Apparently the 240v electricity from the pole gets split into 120v when it gets to the fuse box. Sometimes with a blown utility pole transformer half the box can go out: either the left side (odd numbered fuses) or right (even numberr fuses) loses power. My basement, garage and half my kitchen worked fine.  All the other rooms had dim lightbulbs that slowly went dark.

"How can a soldering iron cause this?!?"

I finally looked outside and saw the street lamps going dark and realized it was a power line/pole problem. For a few minutes as I sat in complete darkness holding a blazingly hot soldering iron I thought I fried my house wiring.

I got to bed at 3am with a power company using a gas-powered generator backfeeding the pole by my bedroom window. Backfed with a regular old orange extension cord up the pole.  It's very important to wire in emergency generators for your home properly: if you backfeed your house with a male plug to your wall you can kill a utility worker.

Wait, so it wasn't the catnip, er, I mean soldering iron that made the lights in the house look like lava lamps? Still seems dark in here, I can't tell if I'm standing in a pile of loose Darlington transistors or those 10uf decoupling capacitors for the laboratory power source being built for the next post...meow.

see atomic particles with your own eyes huh? Part II

So you wanna see atomic particles with your own eyes huh? Part II

Was der Fall ist, die Tatsache, ist das Bestehen von Sachverhalten.

(What is the case, the fact, is the existence of atomic facts.)

-Ludwig Wittgenstein

Wittgenstein was a fascinating weirdo, but in the second proposition to his only (seventy-five page long) contribution to the world of philosophy and logic (the Tractatus Logico Philosophicus) he wrote the quote above. He wasn't denying art, religion, myth, but when speaking of absolute truth there are facts (atomic and otherwise) and then there is everything else.  Stay in there, it gets less boring real soon...

Basically he went against metaphysics (sort of) and Plato, et al and piled on a bunch of stuff about words and the world and truth functions (like actual math functions but with words) and examining the world using language. If any of the above grabs you: search "atomic sentence" and there's a whole world of true/false wordy-math formula semantic whatever. Anyway, Wittgenstein argued for unalterable objects/forms in direct opposition to eastern philosophy where Forms are ever changing, relative substances in a constant state of flux (sounds just like radioactive elements becoming different substances by adding/losing electrons and particles through decay. Think back to the last post about changing the dime's silver "form" to different isotopes 107, 108, 109 and 110. Flux. Change. Pretty much the opposite of Wittgenstein's ideas, but my quest to see atoms isn't.

Anyway, Wittgenstein claimed he solved all the problems of philosophy(!) so there's no need to continue in that vein. Here's an Atomic Facts of my own: I've seen the trails left by alpha, beta and gamma particles with my cloud chamber. This was covered in one of my previous posts. Think of the nuclear cloud chamber like standing in fog and watching bullets zing past you ripping lines through the fog. Cool-but I want more!

This is where my new toy comes in: a radioscope / sphinthariscope. A radioscope is a screen with zinc-sulfide paste smeared on it. It also has a magnifying eyepiece attached. You hold it up to alpha emitting radioactive objects to see tiny flashes of light when the alpha particles hit the zinc-sulphide crystal and form a phosphor (not to be confused with the chemical element phosphorus). It glows in the dark, well actually it scintillates. 

The word sphinthariscope comes from the Greek word for scintillate or sparkle. A sphinthariscope comes with a built in piece of radioactive material to "power" it-a radioscope is the same thing but with the radioactive material removed, along with the bottom of the device so that you can plop it on top of your own radioactive materials.

For $29 you can buy one from United Nuclear-but for about $9 you buy the activate zinc-sulfide and smear it on your own homemade scope. I opted to order one first, I'll probably make one from scratch for the fun of it in the future.

William Cooke made/discovered the first spinthariscope when using a phosphor screen to look for bits of radioactive material he spilled on the floor (been there-done that). He was lighting the screen with an even about of materials, but crawling around on the floor let him see tiny amounts of (alpha) radiation as individual flashes-not just an even glow. 

They became popular novelties in the early 1900s to 1950s: nice brass ones that people took to fancy dinner parties were the "in" thing. The famous Lone Ranger Atomic Ring was a later one that tons of kids received after making their Kix Cereal boxtops in. Then the fad waned.

So how did my radioscope work?

At first there was nothing, but after about ten minutes in a dark room I could see the alpha sparks. My eyes took time to adjust, but the zinc-sulfide coating glows in the dark for a few minutes as well.  At 6400 ISO with a fast f/1.8 lens I couldn't photograph them. Digital camera: 1, human eyeball: 1.

My uranium ore had random green flashes like looking out at a vast field and watching for fireflies to flash. There were some sideways "zingers" and bigger, smeared flashes like lightening behind clouds.

As "hot" as my uranium is to my Geiger counter (which measures beta, gamma and x-ray) there wasn't too much alpha going on. It was nice and subtle and I could have watched for hours, but I didn't like having uranium two inches from my face blasting intense radiation into my eyeball like some brain cancer inducing Medusa.

I moved my radioscope off the pile of uranium and plopped it on top of my little piece of Americium radioisotope 241 (AM-241). AM-241 spews out lots of alpha and a fair amount of gamma radiation. It's what ionizes the chamber inside many cheap smoke detectors: smoke particles block the alpha particles (they're weak) and trigger the alarm.

The verdict with Americium? Wow!! At first it was a dense, waving matrix of corruscating green dots like an old computer monitor from the 1980s that was being reflected in a wavy lake at night. Green dots pulsating, then the dots would surge and swirl like a Hindu mandala (which metaphysically symbolize the universe-Wittgenstein would not approve). 

Imagine the pattern on m my kilim rug, if the rug was hanging on a clothes line and the wind was blowing it toward and away from you in billowing ripples. Mesmerizing!

Sometimes it looked as though the dots were fruit flies or tiny gnats swarming (if gnats glowed in the dark). 

So, while the cloud chamber I built was like having bullets cut trails through fog, this radioscope is kinda like driving a fast car with your headlights off through a pitch black field and having fireflies splattering on the windshield...plus swirling and pulsing like a car wash on that windshield. I have lots of experience with glowing insects on my vehicle (still no idea what the one I took a photo of above was).

The surging and receding coruscating waves appear to be just like the magnetic ferri fluid (iron particles in liquid showing the magnetic field). The lapping waves of radiating particles being emitted in all directions (but viewed as they hit the flat bottom of the radioscope). 

In this flower photo the red tips are like the green alpha dots. By their speed, number and brightness you can infer many things (like the yellow paths). The charge of alpha particles was first investigated with a sphinthariscope, and research on the charge of electrons was furthered by its use; along with the correct form of atoms and their nucleus.

Imagine instead of black magnetic fluid outlining a magnetic field, green dots outlining a field radiation-smashed against the flat viewing window of my radioscope.

With these two easy to make/cheap to buy devices I've seen the paths of radioactive particles and partially how the radiate.

I think I can see the particles too! Meow.

see atomic particles with your own eyes

So you wanna see atomic particles with your own eyes huh? Here's how to do it easily!

Just build a nuclear cloud chamber...for around $7.

Cloud chambers let you see paths left by radioactive particles as they pass through a supersaturation of alcohol vapor. Vapor trails are formed when the radiation ionizes the alcohol mist super-cooled and formed by dry ice under the aquarium while the top of the aquarium drizzles the propanol (very pure rubbing alcohol you must never touch, or Everclear grain alcohol would probably work, as would methyl alcohol like Heet fuel additive). I went with a $7 bottle of 99.9% pure rubbing alcohol. Caution: the 70% stuff at drugstores won't work.

Alpha particles, and beta and gamma rays leave different looking trails in the mist; as do muons, positrons, cosmic rays, electron collisions;--basically ions. X-rays, bremsstrahlung (braking) radiation and annihilation radiation arising from positrons interacting with electrons basically behave like gamma rays.  Some trails are long and thin, some are short and fat, some branch out like lightening: each path can tell you the exact type of particle that just whizzed by! Yes, you can actually see the tracks they rip through the mist. You can even use a strong magnet and "bend" the path of some particles.

What I used: 10 gallon aquarium; metal roof flashing; stiff wire/coat hangers; styrofoam block; socks; wire to use as tie-wraps; 99.9% rubbing alcholol; DRY ICE and some radioisotope AM-241 from an ionic chamber type smoke detector ($5 at any store). AM-241 is Americium (pronounced Amer-eh-SHE-um). You'll see the Am-241 in the video, it's just a flat silver disk that is INSANELY RADIOACTIVE, yet it mostly shoots out 

Don't get confused AM has a number of 95 on the Periodic Table, but this is one of its isotopes (241). Am-241 is so radioactive that all the "harmless" alpha particles is shoots out are so plentiful it actually damages the crystal structure of the element itself! This is like the damage that radioactive particles can do to your DNA to cause cancer. In addition to tons of alpha particles it also emits some gamma particles as well. My Geiger counter can't see alpha particles--just beta, gamma and x-rays and even so it reads around 300 clicks per minute! 

MANY PEOPLE ONLINE SAY THAT AM-241 FROM A SMOKE DETECTOR ONLY PUTS OUT A FEW GAMMA PARTICLES AND THE REST IS SAFE ALPHA. THEY OBVIOUSLY DON'T OWN GEIGER COUNTERS AND CANNOT ANSWER WHEN YOU ASK THEM TO QUANTIFY THE GAMMA RADIATION. 

So do your own homework, buy a $99 Geiger counter (I use a GQ GMC-300e Plus) and don't believe everything on the internet, it can get you killed. At 300cpm what is dangerous gamma particles in this piece of AM-241 is only slightly worse than two of my old glow-in-the-dark wristwatches from the 1930s. Still, the danger is there.

BUILDING THE BEAST

Here's how I did it. Cut a recess in a foam block to hold the dry ice.

Make a wire frame inside an aquarium to hold the socks that we'll douse with 99.9% rubbing alcohol. The long pieces will go near the glass bottom. The aquarium will be upside down with the socks at the top when the unit is working.

Put the socks on and tie them with thin wire. Rubber bands will melt from the alcohol and break from the dry ice. Just use wire bread bag wraps if that's all you can find.

The aquarium's glass bottom is now it's glass top.

I fit the the aquarium on the glass block so it was air-tight and put a piece of THIN metal roof flashing between the dry ice and the inside of the cloud chamber. It looks black here because I had it covered, but it didn't work so I uncovered it. In the video it's bright shiny metal.

I put the dry ice in the hollowed out recess in the foam block. I doused the socks with alcohol. Put the AM-241 on the metal plate. I put the metal plate on the dry ice and the aquarium over everything.

Next I added a light bulb on top of the glass carefully since these 99.9% alcohol vapors are highly inflammable. The light bulb was to add WARMTH to the top of the aquarium while the bottom was super-cooled by the dry ice. This creates the fog of alcohol vapors at the bottom for the particles to leave trails through.

In the video (which gets better halfway through because I re-position the light) you'll see a half-sphere dome of fog over the AM-241 disk and a flower-like cascade of alpha particle trails shooting off the disk. The unit only worked for about 10 minutes after 2 hours of trying. Oddly, even though everyone says it needs to be airtight--the unit only started working once I gave up and started to dismantle it. Once some warmer air hit the inside the fog formed and I started seeing trails!

This could mean that the whole aquarium was too cold. At one point I put a bucket of hot water on top of the aquarium to increase the temperature differential, but it didn't seem to help. I filmed it for a few seconds, and then spent a few minutes silently watching with a smile on my face. 

Almost everything I scavenged for free, including the smoke detector's AM-241. The 99.9% rubbing alcohol was $7 and all gone when I was done. I got the dry ice from the Melvindale Public Library where I work: we had an open house and children's bookmark drawing award ceremony and we had dry ice left over from the ice cream we served. I knew that we'd have dry ice left over, so I ordered the alcohol and built the nuclear cloud chamber a couple weeks before the event. So I guess this is a $7 cloud chamber.

And that's how you can "see" atomic particles. It's a lot more fun than those golf-ball diagrams in your textbooks and tinker toy balls and connectors: like Coca-Cola this is the REAL THING; and it won't give you cavities...but it might give you radiation poisoning...

Yes, you can get great deals on Uranium these days

Yes, you can get great deals on Uranium these days

My (smallest) Geiger counter is a GQ GMC-300e that was $99. It reads beta, gamma and xray radiation. It doesn't do alpha, if it did then this Uranium sample from Lisbon Valley Utah would be about 40% higher! The video was short because as the Geiger got so hot I wanted to move away at high speed.

The final reading was 6200 clicks per minute. My antique radium painted wristwatch was only 220cpm or so! These are very, very hot rocks-like that old film noir movie "Kiss Me Deadly" from the 50s, minus the howling noise.

No relation to the awesome Lita Ford song of the same name.

This sample is unrefined uranium ore. I've tested a few old wristwatches and found Radium in them. Back in the old days companies would paint Radium on watches and clocks and other things to make them glow in the dark! A lot of workers who did the painting died awful deaths, but not before developing disfiguring tumors. A famous group are known as the "Radium Girls" who would purse their lips on their paintbrushes to get a real fine, pointed tip to paint the clock faces with more precision. Turns out putting radioactive brushes in your mouth is a bad idea. Radium is very similar to calcium, it has a bad habit of swapping places with the calcium in your bones and causing massive health problems.


Alpha particles are stopped by your skin. Even a sheet of paper will stop them so Geiger counters that can detect alpha radiation are more open and this fragile: the plastic case on my Geiger is more than enough to block all alpha even if it was sensitive to it. To stop beta radiation you'd need a sheet of aluminum. Gamma and x-rays blast through all sorts of things but are significantly stopped (but not totally) by lead. Surprisingly, scientists disagree on the definition of what constitutes gamma vs X-rays.

I got interested in radioactive things when I fixed an old antique watch. I fell asleep with it on and in the dark noticed that the hands weren't "glowing" but we're actually sparkling! It was so weird that I researched and found that the watch was painted with Radium. On the bottom of the face near the 6 o'clock position was a tiny "Ra" that could only be seem with a magnifying glass. Ra=Radium. Deadly, deadly radium.

After getting me Geiger counter I found another, unlabeled, watch that was even more radioactive in my collection.


Recently I ordered the uraninite ore from LifeTech and they sent it out properly packed and with no problems. It is way more radioactive than my old wristwatches.

So, besides listening to the tell-tale clicking of the Geiger counter what can you do with radioactive minerals and such? Well, my next post will be about the cool Nuclear Cloud Chamber that let's you see the trails left by the path of radioactive particles zinging through a cloud of supercooled alcohol vapor-the best part of that it is super cheap and easy to make!

How did I get interested in radioactive stuff? Well, shown above are my gold Lord Elgin Swiss watch with Radium glowing hands and hour markers and a Uranium laced glass marble. I got the watch for free in a box of 'junk' at a garage sale. I fell asleep while wearing it and in the darkness brought it up to my eyes to see. It was then I noticed that it wasn't just 'glowing' in the dark it was 'sparkling'!!!! This sparkling was a scintillation every few seconds, like a weird mini-lightening strike: kind of slow, like when a big lightening bolt takes a while to branch out in the sky. I did a little research and found out my cool gold watch was radioactive--and the reason it was is that the hands were painted with Radium, sometimes written near the 6 o'clock position as 'Ra'.

The Uranium glass marble changes color in sunlight due to, well: Uranium in the glass. Many antique (and new) glass contains Uranium for this color-changing effect. Uranium glass is also called "Vaseline Glass". It's all slightly radioactive. So are thorium laced gas lantern mantles for camping. The little sock looking wick is radioactive. 

Fiestaware ceramic bowls and plates (especially the red colored ones) are so radioactive that people break them into pieces and sell them to Geiger counter owners like me as a test source!

Name      What is it?                                                                           Distance traveled 
                                                                                                                    through open air
Alpha       Physical particle equaling a Helium nucleus                        2-3cm

Beta          Physical particle equaling an electron                                    2-3m

Gamma    Not radioactive decay, just energy burst                                500m
                   accompanying alpha or beta radiation.
                   The same as an x-ray, but arising from
                   different sources.

Neutron     Physical particle made up of 1 up quark and                   1000s of meters
                     2 down quarks.


Name   Symbol     Makeup                           Charge         Speed       Atomic Mass Units
Alpha     α             2 protons & 2 Neutrons       + +                Slow                               4

Beta        β               1 electron                                -              Fast or Slow                1/2000

Gamma  γ                Photons/                           Neutral        Speed of light                   0
                           electromagnetic waves

Neutron n           1 up & 2 down quarks         Neutral      2.2km/S-14,000km/S         1
                                                                                                 (~5% speed of light)

Notes: 

An AMU (Atomic Mass Unit) is equal to 1/12 the mass of a Carbon-12 atom. 

Slow Neutrons are called "Thermal" and fast ones are called "Fast" neutrons. 

An alpha particle is double positive "++". 

Gamma rays are produced by atomic nuclei and x-rays are created by accelerating electrons, but they are basically the same type of wave energy. 


Lead only approximately halves the gamma/x-ray amounts. A 1/2" of lead stops about half the waves trying to get through. When beta radiation hits lead sometimes a new type of radiation is created that is more dangerous! This is Bremsstrahlung radiation (braking/deceleration). Lead barely interacts with neutron radiation, water or hydrogen-containing compounds such as common paraffin wax are much better shielding material.


By the way, another great place to creep around and find info like this is the Oak Ridge National Lab at  https://libcat.ornl.gov/  which has tons of DECLASSIFIED reports of various techniques for radioactive fun. The directory names look like years, but the files inside them are all scrambled up--so just poke around. A cool file I found was "The Preparation, Properties, and Uses of Americium - 241, Alpha-, Gamma-, and Neutron Sources."