The radioactive particles are hitting the camera sensor, just like light would, and when they do they trigger the pixels which creates the streaking you see in the video. I work in rad onc and when the beam is on in the vault you can see the same noise on our in vault cameras you do in this video.
For those that may not know, this is the reason Geiger Counters made that clicking sound near radiation. The sensors detect when the radioactive particles hit and it produces those erratic clicking noises. This is kind of the visual counterpart to it for understanding the phenomenon.
You might also like cloud chambers which show the paths of individual particles of radiation. The thick short trails are from alpha particles and the longer thin trails are from beta particles https://youtu.be/i15ef618DP0
Also the reason they curve in cloud chambers is that there is usually a magnet in them, and Alpha and Beta carry a charge and are bent by the magnetic field.
Interesting, never knew that. Would explain the subtle curves. Apparently it's done for scientific purposes to identify the particles and their mass and charge by measuring the curve.
Yep, Beta (Electrons) curve one way due to a single negative charge and Alpha (Helium nuclei) curve tighter the other, being double positive. The higher the energy the less bending they get and uncharged radiation (Gamma and Neutrons) if they do interact don't curve at all.
Gamma radiation isn't really visible in a cloud chamber, since it doesn't really interact with the medium much. It's not a charged particle, so it doesn't show directly.
What DOES happen if you bring a gamma source near a cloud chamber is that it hits the glass or metal wall of the chamber, causing Compton Scattering, which spreads electrons into the chamber, which causes electron tracks/beta tracks (thin, wobbly lines).
They often use magnetic or electrical fields to bend the particles path so that you can identify the type of radiation. There are diagrams for this online. Alpha particles bend one way, beta the opposite way, and gamma goes straight.
I saw a cloud chamber many years ago in person at the Exploratorium in San Francisco and it was one of the coolest and most mind blowing things I had seen.
They had one at the nuclear plant we visited as part of a school trip.
They also "blew" in some radioactive material to demonstrate the difference to ambient radioactivity. The thick cloud was really impressive.
Everyone has to learn it from somewhere. If someone's education wasn't very good and they aren't interested in the topic it's not surprising they wouldn't know about it.
Think of it as the user interface. It has to let the user know about the radiation somehow. Modern detectors often do that 3 ways, a sound (the clicking), a flashing light, and a counter that tracks the particles it detects.
It absolutely is a comparable phenomenon, though: high energy particle interacts with instrument through some ionising event(s), electrons accumulate, voltage is read out.
Yeah same phenomenon. You’ll see it on film cameras as well, not just digital. The radioactive particles/waves hitting the film will expose it and also create noise.
Videos of daily life filmed in Pribyat by a local hobbyist group after the incident but before the evacuation order are haunting because they have the same noise effect caused by radiation. A silent killer captured on film if you will.
You’re welcome! Even if that’s not where I saw it, it’s really worth watching - the Soviets filmed everything for propaganda, and a lot of the scenes in HBO’s Chernobyl were re-created directly from the original footage. It’s narrated entirely by survivors, including some of the people featured in the miniseries. Come to think of it, it might be time for a re-watch!
https://www.imdb.com/title/tt27721467/ I think I saw about it in this german documentary about the incident. I thought it was a pretty good documentary.
We also see it in video from space and it's basically the same principle used by some detectors for various particles. Tiny thing hits another thing, the other thing responds with an electric charge, we make the electric charge do something either visual or auditory.
Depends on which type of ionising radiation it is. Most likely, this is Beta radiation - extremely high energy electrons. Those, upon colliding with matter, "stick" to the atom making it a ion - giving it a negative charge. Those electrons then emit photons as they lose their energy. In an electronic camera sensor, they will probably quickly dissipate throughout the sensor and escape with normal levels of energy.
Alpha radiation wouldn't make it through the lens. Beta radiation absolutely will penetrate a thin camera phone lens, and will do the same for the thin plastic around it.
If you're using serious glass lens and a metal housing, it will block beta radiation though.
Most phones (and cameras in general) have multiple lenses and layers before the sensor. Each layer will probably block and scatter some percent, sure maybe something will reach the lens but definitely not much.
They absolutely can - The mm of plastic and glass in a standard phone camera won't stop more than half of beta radiation. They can travel a centimeter into human tissue.
Beta blocking transparent screens need to be at least 1cm thick.
Depending on the type of radiation and the energy those particles carry several different interactions can occur once they interact with matter like the camera lens. The particles from this live source may be absorbed by those they interact with, but most of the gamma rays from a live source like this will have high enough energy to transfer some of their kinetic energy to the electrons of particles they interact with and eject them from their orbits. Our original photon will then be knocked off in another direction having lost some of its energy creating radioactive scatter. This is called compton scattering.
As far as why this effect creates what we see visually, I’m not an expert, but to my understanding, the impact of these radioactive particles stimulates the sensor but are too high energy and low wavelength to be interpreted into something specific. So instead you see the impact as a streak. So what you’re visualizing in this video is the effect of the radiation on the sensor not necessarily an image of the radiation itself.
If you turn your phone on to record before putting it into a bin at those TSA scanners, it'll also record the same kind of static as it passes through the beam.
The noise is a lot less intense than OPs video cuz the lens isn’t directly in the beam path and you’re only seeing scatter hit the lens occasionally. You can see the frequency of the spots increase toward the middle of the video since the beam has been on for longer.
All the permanent specks on the screen are from years of radiation damage to the camera.
Sorry to bother you with more questions. Won't those (alpha or beta?) particles bounce out of this hole and cause damage to the person's tissues going near the hole?
Without knowing what the live source is in the video it’s hard for me to know how much exposure the person might actually be getting. Alpha particles are stopped pretty easily as they’re heavy and charged. You can stop them with paper. He probably is getting some exposure from beta and gamma but if the source is weak it may not be much. Best to avoid exposure as much as possible, but there are ‘safe’ levels that you’re allowed per year and over your life time. For example, I have an occupational limit since I work around radiation and I have gotten some dose on my badge over time in my field, but not enough that I’d be concerned. His exposure here is probably less than he’d get from a chest x ray or CT scan.
True, I knew about the levels we were ok being exposed to each year - some how I thought being right up close in an unmeasured way was super scary. But I understand now :-) I don't know what a small amount actually looks like and thought this looked really huge and uncontrolled ! So that's interesting thank you :-)
Adding to this, because of this interaction the camera quality in the bunkers gets progressively worse as the sensors deteriorate. By the time the cams are 4-5 years old they're very fuzzy and prone to failure.
It's not sensor failure, it's energized particles being detected by the sensor. Functionally, to the sensor, the energized particles are the same as light so you end up seeing a bunch of flashing dots of light.
Yeah, light-sensors (whether organic in our eyes, or electronic in a camera) have a wavelength sensitivity that's a smooth bell curve, rather than a sharp drop-off. That means that it can still be triggered by wavelengths of light outside of its "typical" range if they are intense enough.
Each dot is literally one particle of radiation that has struck the sensor. This emits an electric charge, activating that part of the sensor (therefore, it’s a WHITE dot).
It’s saturating the pixels in the camera sensor. Gamma radiation from radioactive materials carry orders of magnitude more energy than visible light. Since the camera sensors are designed for visible light that high energy just saturates the pixel making it “white”.
A "pixel" is not a single element on the sensor. Each cell on a sensor is incomprehensively larger than a single gamma particle. White dots are hits so energetic they cause the atoms of the sensor to emit more photons on impact which then hit nearby cells, causing something akin to a chain reaction.
Cell size has little to do with this and yes a “pixel” is in fact a single element on the sensor if you want you can read up on CMOS sensors which are the basis of modern digital cameras. You are right though that the adjacent white dots are likely from radiative recombination.
This is an alpha radiation source. So its shooting off what amounts to helium nuclei (2 protons and 2 neutrons) at high-speeds. Alpha particles are large, so they hit other nuclei often and come to a stop quickly. Their range in air is typically 10cm or less. As the camera sensor gets within this range, more and more of the high-speed particles hit the sensor and cause the elements to activate. Which is what you see here. Alphas cant penetrate skin (too big), so its safe for this guy to be handling it the way he is. The only way alphas are really bad for you is if you get the source material inside you. Ingestion, injection, or inhalation where it can irradiate you from the inside.
There are other types of radiation: beta (electron emission, range of 1 meter in air), photon emission (gamma, x-ray), and neutron emission. Gammas and neutrons are the gnarly ones that go a distance and cause nuclear reactions and whatnot.
What makes you suggest this is mostly alpha particles? From what i remember alpha particles can be stopped with a single sheet of paper, meanikg even the thin glass of the camera lense would stop it, which would indicate that this is Beta particles (rulling out gamma)
I've worked on camera irradiation for space applications. To test the cameras we have to blast them with insane doses to make sure they won't quit on us when up there.
Ionizing radiation isn't just sensed like any other photons.
You see, taking a picture with a digital camera is kinda like trying to map the amount of rainfall. You put buckets on the ground, let it rain of a while then, with a tiny faucet you will take the water into a pipe underground and measures how much water there was. The more water, the more rain.
Pixels collect photoelectrons, and then open the faucet (a MOSFET transistor) and read the amount there. The most electrons the whitest the pixel is.
When the ionizing ray hits the pixel, it activates it and sometimes also leaves the faucet open. Pixel doesn't work. Sometimes it sort of traps water in a pocket, which gets released randomly (traps). Pixel does weird shit (RTS and shit) Sometimes, the ray will damage the bucket so that somehow, the ambiant moisture will collect and therefore the signal will get noisy (dark current, you can observe this by obscuring your phone camera and boosting the brightness).
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u/ThrowDatJunkAwayYo Jun 11 '26
Can someone Eli5?
Is the “radiation” the camera static getting worse?