I bought a geiger counter, but there was nothing radioactive around the house, until I discovered you can gather radon decay products using electrostatically charged baloons! The article I referenced: sciencedemonstrations.fas.har...
@@jasonpatterson8091 FBI and RCMP have a wonderful working relationship and it's not out of place to have an FBI agent doing an interview/investigation in CA (with RCMP support obviously).
Indeed. Have faith in your audience of similarly minded excentrics to find the bottom of this rabbit hole a wonderland they are grateful they didn't have to explore personally! So much to do, so little time...
Perhaps the cause of the strange 36 minute half-life is because the half-life isn't really 36 minutes. As you've noticed, the radioactivity first increases and then decreases - the model is thus comprised of more than one relevant half-life. For example if you conjecture the decay has two dominating steps you should fit your model to en.wikipedia.org/wiki/Radioactive_decay#Chain_of_two_decays rather than estimating a single half-life.
Good thought. The physisists behind the linked article probably wouldn't think of something like that. After all it not like they write things like "Since we do not know in what proportion the daughter nuclides of radon have been collected on the balloon, it is not at all clear what half-life has been measured." and later on discuss their use of measuring equipment to figure out the specific gamma frequencies to determine this proportion.
Maybe this set of lists look down for the 10s of minutes list (for bismuth lead chlorine maybe chlorine from tap water??): en.wikipedia.org/wiki/List_of_radioactive_nuclides_by_half-life here en.wikipedia.org/wiki/List_of_radioactive_nuclides_by_half-life#103_seconds_(kiloseconds)
@@matthiasrandomstuff2221 I started with the (somewhat dubious) assumption that there was only Po218 on the balloon to begin with, and solved the differential equations to obtain the amount of Pb214 and Bi214 as functions of time. I then modelled the number of Geiger-Mueller clicks as the decay rate (lambda) for Pb214 times its quantity plus similarly for Bi214, assuming that no alphas are making it into your detector through the solid plastic. The resulting curve looks quite a lot like the one you see, and if I estimate a "half-life" in the same way by drawing a straight line on the log plot between the rate at 90 minutes and the rate at 250 minutes, I get an apparent half-life of 38.5 minutes. I think the confusion might be caused by the fact that there is a chain of processes taking place -- it takes 9.5 minutes to reach peak rate of lead decay and 28 minutes to reach the peak rate of bismuth decays, and a substantial amount of new bismuth is still being added through lead decays at that time (though the polonium is basically gone). If instead, I measure the apparent half-life between times farther along, say 500 and 1000 minutes, it converges on 26.8 minutes, the half-life of lead, which makes sense because the decay rate of bismuth is higher, so eventually lead is the bottleneck for all events.
I have a degree in Physics and I don’t have any answers for you. But I do have a funny Geiger counter story. For a Modern Physics Lab we were tasked with taking a Geiger counter around campus and logging radioactive sources. I went into a local WalMart to test the bananas and got kicked out by an irate Karen who thought I was making the food radioactive 😂
It depends on your detector, but i doubt any of them are alpha detectors, so most likely you would only pick up beta and gamma decays. Looking at the decay series for Rn222, I think what's being picked up is the decay of Pb214 (hl=27 m) and the decay of Bi214 (hl=20 m). These two happening back to back are giving you the 38 minute half life. The decays of Po218 and Po214 don't get picked up because they're alphas and for the time scale of your experiment, Pb210 is effectively stable.
I think you observed the transient equilibrium of the radon decay product my friend. I could be wrong but there is more than 1 isotope with short half life, a gamma/alpha spectrum would help identifying the culprit but keep in mind that you also detected a combination of gamma and beta radiation (maybe some alpha depending on the tube used ) also, the braking radiation of the beta and alpha particles will mess with the result a bit.. great video sir!
Well I learned two things today - first that you can collect radon daughter isotopes in the form of dust (more or less) and that radon that is generated from thorium is called thoron by the folks in the know. I was reading the article you stopped on regarding the decay products of radon and saw the mention of thoron and fell into an even deeper rabbit hole about it. Sincere thanks - I always enjoy learning something new and interesting, especially in an area where I'm reasonably knowledgeable already. And I would love another video on how your dehumidifier/HVAC affects background radiation in the house.
After I built a geiger counter myself I discovered the same thing, but I used the dust that collects on the screen of an old CRT television after a while. Just let it run for 10-20 minutes, then wipe the screen with a damp paper towel.
I am impressed that you were able to get so good data from that. As others have pointed out it seems likely that you see parallel and consecutive decays overlaying.
This is pretty cool! If you're in the market for radiation detectors, I gotta recommend the Radiacode. It's not a Geiger tube, but uses a scintillation crystal, and it detects the energy level of gamma radiation. The benefit is that it makes it really easy to determine which isotopes you're seeing. It also easily hooks up to a computer or smartphone for data analysis.
Brings back memories of when I used to ride my bike to work at the nuclear power plant. I could not get my wet cycling clothes and shoes past the radiation. monitors to get into the office. Others had difficulty getting in with wet coats from rain. Those Radon daughters really stick.
I have a few friends who are certified Health Physicists, and I can't wait to show them this video to see what they think could be behind the odd half-life. These guys are super knowledgeable in their field.
I thought the point of this channel was for random stuff with almost no views. It's also one of the channels I get excited for. Nerding out on data collection, even other people's data collection, is not the kinda of thing we get enough of on RU-vid. I really wanna know how much change you see running filters and HVAC. Random stuff! It's interesting!
Many years ago, I installed radon evacuation systems. I honestly do not remember how we tested for levels, but I do remember it taking a solid week. It's crazy that it decays so quickly (hours to days), but it is "around" long enough to give people cancer, etc. Of course, that's in higher concentrations. Thanks for the interesting video! As usual, it was not a disappointment.
it isn't around that long, just that the radon in your house keeps getting replenished from he ground. I don't know what to think bout radon. Has there ever been anybody who conclusively died from radon in their house? Surely, there should be some extreme cases, right?
@matthiasrandomstuff2221 I do agree with your statements, definitely. As far as indisputable evidence, I can't answer that. I only assume what I was taught is correct; that exposure to copious amounts of radon is believed to cause lung cancer. I can only assume since it collects and has time to mutate cells. I agree there are probably minimal "accounts" directly related, but I also know there are some areas (at least in the U.S.) where there are exponentially higher amounts being released from the soil. I seem to remember that farm land or areas that were forested for long periods are worse than those that do not have as much organic material. Thanks for questioning everything like you do! Sometimes, I just give in, and other times, I fight for what is potentially the truth. Of course, as you have shown many times, facts/data can be used to make statements that may not be correct, whether intentionally or not.
@matthiasrandomstuff2221 The answer lies in the statistics - not single cases. Some people can smoke their whole life and die at age 95. Others haven't smoked and die of lung cancer at age 30.
Of all the hazards you are facing right now, Radon probably isn't one of them. With your deep rich soil, you probably aren't that close to igneous bedrock where the radon comes from
On the Fnirsi GC-01 you can add the audible 'click' sound of the particle counter with a resistor. Foton Gamma has a demo of this process on his channel. Appears to be a very simple process.
Really awesome video! For the half-life mystery, are you computing mean-life or half-life? The mean-life is what you get from just measuring the exponential slope. There's a factor of ln(2) difference to get the half-life. So for 214Pb: mean-life = 38.9 min, half-life = 27 min
This is awesome! I love how you mix electronics, woodworking, science, math, etc. to scratch that curiosity itch! It's always practical, insightful, and to the point. If I ever got the guts to start recording myself, I'd model it after this.
Love your videos Matthias. I'm drawn to your channel for your frugal, MVP, and behind the science approach to science, making, and hacking. Keep posting and I'll keep watching :) John from Norway.
This is facinating stuff! Short of having the measurement tool, it'd be a great experiment for older kids. If you do more videos on it, you'd get my view for sure! It might be a good opportunity for a collab. Not with me, because I'd be useless, but some youtubers in the radiation field would sure jump on that. Busting a few myths and what not.
Having just installed a radon abatement system in my home, I found this video very interesting, and would love any further trips down this "rabbit hole."
I'm one of the people who would appreciate a follow up. Maybe in the future you can just mention in another video that you've added notes about the radon decay to this one.
The radon decay chain is primarily a series of alpha decays, where an alpha particle, which is a helium nucleus containing two protons and two neutrons, is ejected from the nucleus of the parent atom with the alpha particle typically having a few million electron volts of kinetic energy depending on which step in the decay chain we are talking about. Such an alpha particle slows to a stop in a few microns of travel in a solid by losing energy to electrons which it kicks out of atoms as it zips past. These ejected electrons produce x-rays as they collide with other electrons and the holes in the atomic shells left by the ejected electrons also produce x-rays as electrons further from the nucleus jump into the hole closer to the nucleus. I think that it is these x-rays that your Geiger counter is detecting, since alpha particles only travel a few microns in a solid they would not make it through the glass wall of the Geiger tube. By the way, a common detector for alpha particles uses an aluminized Mylar window, which is thin enough that some of the alpha particles can penetrate. Most fast electrons, that is beta particles, are stopped by a single sheet of paper, and would not make it through the glass wall of the Geiger tube.
I am sure you know by now what gets views and what doesn't. I will only say that I love this type of video and will appreciate however many of them you feel like doing.
Very informative, thanks. You can make your own GM tube that will pick up everything, even alpha. You just need a copper end cap (2") and a BNC connector. You put the connector in the center of the cap. Then solder a rod from the BNC center tap that goes most of the way down into the cap. Place the cap over the sample with a smidge of pure alcohol off to the side (it prevents multiple triggers from the same particle).
A good detector is the Better Geiger project. It's actually a scintillation detector with pretty basic functionality, but it has a whole range of modding options as most the hardware is open source.
Another scintillation detector is the Radiacode 102, and the nice thing about scintillation detectors is you can actually determine isotopes, as they can measure the energy of the particles.
It costs almost 5x as much and looks like it was 3D printed. Surely, a sensible company would charge an extra $30 for something that doesn’t look like absolute trash.
Always something new and interesting. For pulse accumulation, I'll use one of those little Arduinos and have it accumulate the pulses, taking into account for overflow of the 8 bit register and then talk to the Pi via its unused console serial port. Came in handy for a weather vane wind speed signal.
your dryer lint is gonna emit alpha particles (if anything), which a "gamma beta xray" (*not*, despite labeled as such, "nuclear radiation") detector won't pick up on. same for radon by the way, your detector would have to see secondary-decays to pick up anything.
I hope you make more videos on this topic. I’ve found that when observing barometric pressure and radon levels in the house, their fluctuations are closely related and the radon lags behind the pressure, as you’d expect. It’s the biggest influence over radon levels that I’ve been able to determine. in my experience, anyway.
Oh that is bizarre. Today I learned. Sounds to me like it's time for you to build a competent geiger counter using an arduino/pi and the basic board you've got, since it just needs a GUI. Side note, I love how many random wooden gadgets you make on the channel that fufill such a specific purpose. "This one here is designed to hold a balloon against a geiger counter" "This one throws applesauce packet lids"
Static charging units - cats are ideal (dog fur is generally rougher) - if you lack for cat, borrow from a friendly neighbor or repurpose one of your traps or a cage trap and catch, rub and release stray cats (maybe captured squirrels can have their tails pulled gently from a cage trap and used to activate the static charging mechanism without activating biting or scratching modes of action - a standard candle so to speak).
I'd love to see the faces of the owners of the neighborhood kitties, if i'm chasing them with an inflated balloon, desperately trying to get them to sit still for a few seconds...
you should check out your ceramic products like your sinks and toilet as when i was hauling loads of these in trucking i showed excessive radiation in checkpoints.
Hi Matthias, long time viewer first time commenter. This video is one of a trend where you become interested in a topic, then follow a path to learn more about the topic using your engineering and programming background. I hope you would consider a "guided" follow along for the more hands on viewer! I have children a few years younger than yours, this is the first video that seems simple enough where I would love to follow along and create a small electronics project with the kids. I can already see them running around the house testing things to see what clicks more. Thanks for the video!
a follow along for an electronic project is useless. Because something will go wrong for you that didn't go wrong for me, and now, without in-depth knowledge, you don't know what to do. So instead, get enough general knowledge of a topic to be able to execute your own projects without handholding, so you will be able to debug what will inevitably go wrong.
I have a GQ GMC-500 (there are a few different models) - I really like it, the firmware and UI is pretty decent. It has a 18650 Lithium battery that is easily replaceable. My grandpa was a watch and clock repairman and I have a ton of old radium painted clocks hanging around. Highest reading I've got was 45,000cpm off of a clock from an old aircraft(he was also in the RCAF). Ill have to try this radon trick in my shop. If I leave the shop closed for a few days and don't run any ventilation the radon can get up to 250 Bq/m3. I try not to let that happen.
I have an air exchanger, which is necessary to be run 24/7 because radon does increase to unhealthy level. I use an Airthings meter to keep track of it.
I have a radon measuring device (airthings). The count was pretty high in the basement. I have to leave windows open to avoid high levels of radiation now. I have neighbours that used to sleep in the basement until I told them... Now they sleep upstairs. Nice topic, of what most people have no idea.
@@davelowe1977I guess that is outdated. Back then, people used to visit caves with high radon concentration for health reasons. Nowadays, common understanding is, that each little tiny bit of radiation is dangerous.
With respect to residential Radon remediation (at least for the moment), there's very little variation in the consumer products that are available to homeowners. Using static-electricity as a gathering tool could have some serious potential in terms of its practical application. So far, the typical method involves collecting radioactive particles _before_ they go into the house, but plenty of houses out there can't easily be buffered by a low-pressure cushion in this way. For such houses that test high, I can imagine a sort of baseboard-level electrostatic device that solves the problem before it reaches breathing level. As usual, your simple, downright empirical approach delivers. Even if this idea is a total dead-end, this video has really challenged my thinking.
@@paulkolodner2445 It probably does, for better or worse. After making that comment, the problem I started to think about was how one might _clean_ a large electrostatic filter. Note that Radon isn't really dangerous, but its breakdown products can be, and they have a much, much longer half-life. If I were you, I'd be interested to hear what a radiation detector has to say about my electrostatic furnace filter ~ especially since some of them get marketed as "lifetime."
@@pocket83squared Excellent suggestion - a functioning filter should always be radioactive. That's a comforting thought. However, I am pretty sure mine work, because they are always covered with dust when I clean them every 3 months. Plus I replaced them a few years ago, just to be compulsive about home maintenance.
i live a few miles away from two massive uranium mines (one active and one inactive). every single house here has a radon pipe to make sure that radon in the soil has a path to flow through the house that doesn't mix with the air we breathe. from what i understand, its literally just a big pipe (i think its 4 inch PVC) that is set into the slab in the basement so its open to the soil, and it runs straight up to the roof. we can all get radon test kits from the state for free too which is nice. i've measured background radiation numerous times over the years, and its actually not much higher than other places without uranium ore. living my entire life here will net me about one extra chest x-ray worth of radiation. i've never though to do the experiments you did here with the balloon or to test my dryer lint, and now i think i will have to test it to see how strong the radiation is haha
Something that seems to be missing from the discussion here: Radiation emitted outside the human body is much less damaging than radiation emitted from inside the human body. This is what makes radioactive dust so much more dangerous than high background level radiation. Radioactive dust can be inhaled directly, or settle on foods and be eaten; in this case, the radiation originates inside the body and is absorbed directly into organs that have a low cellular replacement rate. Radiation from external sources must pass through air, skin, and muscle before getting the chance to be absorbed into internal organs; skin and muscle have a relatively higher cellular replacement rate, so radiation damage to them is much less likely to result in cancer.
Great to see your old geiger counter. The moving coil panel meter was made by my first ever employer Sifam (based in Torquay in England): a proper old school engineering firm where I learnt to be an software engineer as we replaced the analogue instruments with digital. I wonder which were the better?
Really interesting. You are to be commended on your analysis and research. It would have taken a lot of study and tinkering on your part to make this seem “easy”.
Can't post a direct link, but have a look at the article on ReseachGate: Ionizing Radiation Carcinogenesis Otto G. Raabe, University of California Davis This goes waaaayyyyy above my head so I don't pretend to understand it, but section 3.2 looks at radon decay. "While 218Po comes to equilibrium with radon in about 20 minutes, it takes more than 2 hours for 214Pb and 214Bi to approach equilibrium." Maybe this explains why your graph increases for the first 20 minutes before starting to decrease?
if you live anywhere that has transient radon, a great place to find radon daughters is the dust that gathers on an old style CRT display. Thank you for this video. The next tier is buying a gamma spectrometert, like Spectro 1 Pro Mobile Spectrophotometer. Just FYI.
I like videos like this a lot! The kinetics of series reaktions is not that difficult. It is not uncommon for the activity to rise in decay series. When you take pure Uranium and wait as the decay products "fill" the chain the activity gets higher... (you have to wait a bit longer ;-) )
I'm 100% interested in this my personal dosimetry occasionally picks up more than 1msv at home . I've assumed it's radon. And I'd like to mitigate it in the future
When Matthias started talking about the difficulty in consistently charging the balloon, I half expected him to say something like, "so I build a Wimshurst machine..." and go into a short build segment.
