Shulou(Shulou.com)11/24 Report--

Knowing that radiation doesn't make you immune to radiation, but at least it won't scare you to death.

Earlier this month, a short video went viral on video sites and social media at home and abroad. The video photographer pointed the phone camera at a strange metal jar and opened the white lid on the jar, resulting in a noticeable blur and a lot of white noise.

As if it wasn't enjoyable enough, the photographer tried to put his hand on the jar and the noise disappeared; after taking the hand away, the noise appeared again.

Some comments are starting to make the video scary. They say the jar in the video is a lead can, which is used to transport or store radioactive material, and the noise in the picture is a sign that the camera is being exposed to radiation. They went on to worry about the health of the video authors: they dared to be exposed to radiation, fearing that they would not have one foot in the coffin.

Other netizens try their best to find the loopholes in the video in a scientific spirit of skepticism.

The original author of the video is a Twitter user named Rye Pony, who actually uploaded two videos on November 3.

In the follow-up video, Pony solemnly pulls out a Geiger counter designed to detect radiation, accidentally holding it and dropping it on the table. He picked up the counter again and pointed it at the inside of the mysterious jar. The counter immediately gave an alarm, the sound became more and more urgent, and the numbers on the screen continued to climb, as if there was real lethal radiation.

Half an hour after the video was uploaded, Pony sent a reply, hammering himself: "these are all fake."

The first video is "edited". As far as today's video editing software is concerned, falsifying the blur and noise caused by radiation does not require much technical content, just adding a mask or mask.

The act of covering the jar with your hand is all the more obvious. Most radioactive materials produce gamma rays that are so penetrating that they cannot be blocked by the human body. Assuming that Pony was really filming highly radioactive material, even if he reached out to block the lid, the noise in the picture would not disappear so obviously.

In the second video, Pony deliberately uses something akin to magic: pretending to be slippery, throwing away the Geiger counter, distracting the audience and placing a small piece of pitchblende next to the jar.

The uranium mine is radioactive, but the radiation intensity of a small piece of ore is not as high as he thought. He had to stick the ore tightly to the Geiger tube on the Geiger counter to make the counter sound the alarm. In the video, the maximum number obtained by the counter is 35.62 μ Sv / h, that is, ionizing radiation of 35.62 microsieverts per hour.

In order to improve the reading experience, the original picture is reversed by 180 degrees. The so-called "ionization" in ionizing radiation means that the corresponding rays or particles have sufficient energy to impact electrons in molecules or atoms and detach them from the original medium. Whether the medium is a mechanical part or a human cell, it will lose its original nature and function after being exposed to excessive radiation.

As for Sv,Sievert, it is a measure of the effect of ionizing radiation on the human body. One sievert equals 1000 millisieverts (mSv), while one millisievert equals 1000 microsieverts (μ Sv).

We often say that "putting aside the dose to talk about toxicity is playing hooligans", and the same is true of ionizing radiation. Ionizing radiation exists in almost all things that human beings can come into contact with. Any ordinary person living on the earth is exposed to 2.4 mSv (0.27 μ Sv / h) of radiation every year.

Radiation of about 0.1 μ Sv per 150g (about 1) banana has been confirmed that the radiation dose of 100mSv (1000000 μ Sv) will cause obvious harm to human health. Because the human body has the ability to repair, as long as not long-term or direct exposure to radiation, a healthy adult can withstand radiation in millisieverts. As a reference, a chest X-ray examination will bring about 7mSv radiation; a whole-body CT examination will result in a radiation dose of about 10-20mSv.

By contrast, the radiation from that piece of uranium ore is far from deadly, regardless of the attenuation caused by the physical distance. If Pony is not stupid enough to wear uranium ore as a necklace on his chest 24 hours a day, or to take it out from time to time like an old man's walnut, we don't have to worry about when he will die.

On the Chinese Internet, this deliberate act of creating controversy, gimmicks or risks to attract traffic is generally referred to as "fishing". Pony did not explain his motivation for uploading the two videos, and although he was quick to refute the rumors himself, he could no longer stop the video from spreading around the world for countless video porters to continue fishing.

Tuyuan Zhihu @ Dalazan Lion, but before Pony, there have been similar cases of using netizens' knowledge blind areas to deceive responses on the Internet, and not just one.

In October of this year, for example, a user on Reddit posted such a fishing post: "who can tell me why this yellowish brown stick can't take a normal picture?" The post is accompanied by a photo in which the periphery of the stick is covered with white spots, much like the noise caused by the radiation shock lens.

The stick is engraved with a long string of English, such as "dangerous", "radioactive", "Drop & Run" and the words "Co 60". Cobalt-60 is an artificial radioactive isotope that is highly radioactive and is commonly used in radiation therapy, sterilization or disinfestation of cancer.

There is also a line below that says "3540 curies". Curie,Ci, which comes from the famous scientist Madame Curie, is another measure of the radioactivity of matter.

If this is true, by the time you see and see the words with your own eyes (assuming you are less than a meter away from the stick), your radiation levels have exceeded 40Sv per hour. "leave it and run" will at least guarantee that you will survive today.

If you don't have any protection and insist on stuffing it into your pants pocket, you'll have 15 minutes at the most.

"it should have written 'you are dead'" after knowing the power of the cobalt-60 and then looking at the original paste, you can see doubts everywhere-it is impossible for ordinary people to easily come into contact with an unshielded piece of cobalt-60. after contact, it is even less likely to take out a mobile phone to take a photo.

Enter the warning slogan "Drop & Run" in Google's search bar and we can find the following two results. The first is the original of the stick-a sample of cobalt-60 sealed in the Los Alamos laboratory in the United States, with exactly the same inscription on it.

At the bottom, "7-1-63 (1963)" is the date of production of the cobalt rods. The second is the real origin of the original photo-a website where users can upload 3D printed models. Some good people made a model of the sample of the cobalt rod and made several "seller shows". The author of the original post randomly picked a photo, and P was marked with white spots.

Tuck this model stick into your trouser pocket and you will only feel a little heavy after 15 minutes.

Even if it is not checked from a journalistic point of view, there is no blur in the picture itself, and countless white spots are surprisingly fake.

Camera devices, such as smartphones or digital cameras, achieve imaging by converting optical signals into electrical signals. At this time, once there is strong ionizing radiation into the sensors in the lens and equipment, the driven electrons produce redundant electrical signals, forming the flashing noise we see.

Unlike visible light, the gamma rays emitted by cobalt-60 cannot be captured and reflected by the lens, which will impact the entire sensor. In reality, the radiation noise should be all over the whole picture and the whole picture, not just around the source of the radiation.

3 in such fishing posts, no author really, as the commentary said, "do not know the radiation in the radiation" and play with their own lives. They knew exactly what they were doing, and even if they showed a real source of radiation that caused the Geiger counter to alarm, it would not kill them for a short period of time.

As mentioned earlier, the influence of these fishing content spread all over the world, including Russia, of course. Elsewhere, netizens will scold at most two words after discovering the nature of the post; but in Russia, where there are a large number of cruel people, there will always be people who are not afraid to put them into practice for the sake of a joke that cannot stand scrutiny.

In Russia's Pikabu forum, there is such a ruthless person, the net name "Snater". On November 5, he uploaded a video as an official response to the Pony fishing video.

According to Snyder's reply in the post, he is responsible for managing a geophysical probe that can detect the depth and thickness of rocks and coal seams by emitting gamma rays. The source of the gamma ray is a small piece of cesium-137. What Snett does in the video is to disassemble the machine, remove the cesium-137 inside, and place it in front of the phone camera.

This piece of cesium-137 produces 0.2mSv / h radiation, but it doesn't matter if you keep it in your hand for a few minutes. Although its radiation level is much higher than that of the uranium ore in Pony, Snyder's video images have little visible noise. If Snyte didn't lie and cheat, his video would be the hardest and most convincing counterproof.

However, just refuting the rumors can not completely solve the common doubts. We now know that ionizing radiation does cause noise in the image of the camera. However, how much radiation does it take to produce noise? Further, can we use these noises to use smartphones that everyone is using as instruments to detect radiation intensity?

Neither of these questions is that easy to answer. In view of the huge differences in sensor sensitivity among different camera devices (different brands of phones may get different results), it is difficult to find a precise value that will make the picture start to produce noise. Ionizing radiation is also divided into three or six or nine grades, each with different energy and penetration, and the accuracy of measurement will also be affected by this.

Different types of radiation have different degrees of penetration, such as alpha particles, which cause no less harm than other radiation, but the penetration is weak and will be covered by the shell, lens, and even human skin of the equipment. it generally does not pose a danger on the outside of the human body, and it is difficult to make the photosensitive devices in the equipment produce noise, so it can only be detected by professional equipment such as Geiger counters.

Americium-241, commonly used in smoke alarms, releases X-rays commonly used in alpha-particle medicine, as well as highly penetrating gamma rays, which are easy to produce noise because CCD and CMOS sensors, which are widely used in camera equipment, are relatively sensitive to these two kinds of rays.

X-rays of 110 μ Sv / h can cause noise in CCD cameras. Image source Youtube@bionerd234 picture noise is obviously not an ideal means to quantify radiation. However, it is the sensitivity of CMOS sensors to radioactive rays that makes it possible to detect radiation with mobile phones.

Since 2011, there have been several App phones on the market that claim to detect radiation through CMOS sensors, such as the WikiSensor on Apple's platform, the RadioactivityCounter and GammaPix on Android and Apple. When using these App, you need to paste opaque black tape on the camera to block the interference of visible light and let only the rays that need to be detected enter the sensor.

The accuracy of the data obtained by WikiSensor using these App interfaces is completely incomparable to that of professional equipment, but a great deal of research in the scientific community is willing to stand for them.

A report published on the website of the journal Nature in June 2021 wrote that using sensors built into smartphone cameras to detect radiation is "applicable" enough to detect the presence of radiation before it reaches dangerous levels.

The study in the report specially used an old iPhone 6s, installed RadioactivityCounter, and used a gamma-ray emitter with cesium-137as a control experiment.

According to the experimental records, the error rate of App data is only 1.44% at a radiation dose higher than 100 μ Sv / h, while at a low dose of about 1.25 μ Sv / h, the error rate increases to 79.16%. Considering the different sensitivities of different CMOS sensors, new phones with more advanced sensors are more sensitive and more interfering.

Although smartphones are prone to mistakes in low levels of radiation, they can definitely come in handy when you do have a radioactive leak.

With the application of nuclear energy and the popularization of radiation in medicine and industry, people have more and more opportunities to be exposed to ionizing radiation. Compared with professional devices such as Geiger counter, smartphones with CMOS cameras are more popular and cheap, and the phone itself has its own data processing capability and battery life ability, which is easy to operate and easy to access, so it has the potential to become a portable radiation monitoring device.

Presumably over time, any ordinary person will have the ability to monitor and quantify radiation. Of course, we all hope that we don't need this knowledge and radiation testing App for the rest of our lives, but by then, there will be fewer misleading fishing posts on the Internet.

This article is from the official account of Wechat: game Research Society (ID:yysaag), author: Zhaoyue

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