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If you’ve ever gone on a flight, then you know the drill: you have to go through security where you’re asked to place all your personal belongings in a tray, which goes through a scanner while you yourself pass through a metal detector — or more recently, a whole body scanner.
Have you ever wondered how they can see the contents of your bag without opening it? Perhaps you’ve wondered if what they’re doing is harmful for the electronics in your bag. In this article, we’ll explain what X-rays are, how they work, and how they might affect your electronic devices.
What Are X-Rays?
X-rays are a type of electromagnetic radiation, similar to visible light except they have a much shorter wavelength and a much higher frequency. An “individual X-ray” is just a photon, and it has more energy than a photon of visible light. This increased energy is what allows an X-ray to travel through objects while visible light is simply absorbed or reflected.
It’s important to note that while X-rays are a form of radiation, they are not radioactive or created by radioactive substances. Any effects that happen are a result of an X-ray interacting with a material as it passes through it — there is no “lingering X-ray residue” to worry about.
How Do X-Rays Make Images?
X-rays can be used to create static images (like a photograph), “live” images (like an overhead projector), or even 3D images (i.e. a CT scanner). In all cases, the X-rays are generated in the same way and they interact with objects in the same way, but airport scanners only use the “live” variety.
To create an X-ray, you need an X-ray tube. This tube fires electrons from a copper cathode to an anode typically made of tungsten, molybdenum, or copper. As the electrons hit the anode, they slow down and generate both X-rays and heat. The anode is angled so that the X-rays are emitted in a specific direction.
To create an image, you need a way to measure the amount of X-rays that travel through an object, which is why X-ray image receptors are placed behind the subject. Denser materials, like bone and metal, prevent X-rays from passing through while other materials, like skin, allow them to pass through fine.
In an airport scanner, the image receptor is equipped with a material that lights up when exposed to X-rays. So objects that block X-rays — such as your phone or laptop — will show up as dark on the image while everything else will be bright. An image intensifier is used to make the contrast even clearer.
Of course, the image doesn’t have to be plain black-and-white, which is probably what you’d expect from an X-ray image. In fact, most modern scanners have the ability to colorize the image based on density ranges to make certain objects easier to identify.
As for checked luggage, they actually go through a CT scanner instead, which is a whole different kettle of fish. X-rays are still involved, but they’re emitted from multiple points in a continuously rotating ring, which are then used to generate a 3D image that shows all of the contents from any angle without having to open it.
Can X-Rays Damage Electronics?
X-rays are a type of ionizing radiation, which means that the photons have enough energy to knock electrons out of the atoms they come into contact with, creating positively charged ions in the process.
In large doses, ionizing radiation can harm biological tissue by damaging cell DNA faster than it can be repaired. But electronics aren’t made of biological tissue and they don’t have any DNA to worry about. So can X-rays cause them damage? Not in any significant way, no.
Magnetic Data Storage
Magnetic data storage devices, such as hard drives and floppy disks, work by using mechanical arms that read and write to magnetic regions of rotating platters. The polarity of each region represents either a one or a zero, which are the binary values used to store data electronically.
While these devices are delicate around and sensitive to magnets, they’re impervious to all forms of light, including X-rays. You probably wouldn’t want to take a portable hard drive through a metal detector — and definitely nowhere near an MRI machine! — but it’s perfectly fine going through an airport scanner.
Flash Data Storage
How about your solid state drive, SD card, or USB thumb drive? Again, nothing to worry about here. These use transistors, which either allow electrical currents to pass through (representing a one) or prevent electrical currents from passing through (representing a zero), and that’s how data is stored.
X-rays can theoretically affect flash storage by turning a stored cell (representing a one) into an erased cell (representing a zero). If this happens to enough cells, it could cause data loss, but the intensity of the X-rays used in an airport scanner is so low that this never actually happens.
Computers & Tablets
Computers and tablets don’t have any components in them that are photosensitive, either to visible light or to X-rays. You don’t have to worry about putting your laptop in the X-ray machine.
Airport security will ask you to remove any laptops from your bag, but not because it needs to be treated any differently from the rest of your luggage. Rather, laptops tend to contain dense circuitry which can obscure everything else in your bag.
TSA-approved bags, which allow you to leave your laptop inside the bag, work because they have special laptop compartments that prevent the laptops from interfering with all of the other contents in the bag.
Mobile Phones & Media Players
Like computers and tablets, mobile phones — smart or otherwise — don’t use any photosensitive materials in their construction, so they won’t be damaged by X-rays. Because they’re much smaller, you also don’t need to worry about them obscuring much of your carry-on luggage, so they can stay in your bag.
Cameras & Camcorders
So far we’ve been talking about photosensitive materials, so you might be thinking, “What about cameras and camcorders? Their sensors are photosensitive — that’s how they work!”
While yes, these sensors are sensitive to electromagnetic radiation, they’re protected by shutters and the device enclosures. You might have some trouble trying to capture a long exposure of the inside of the X-ray machine (seriously, don’t do this), but if your device is not actively capturing light, there’s no problem.
Undeveloped film is the one thing that you might have to worry about when going through an airport scanner. The higher-energy X-rays are able to pass through the plastic film container and could ruin your images.
However, you only really need to worry about this if you’ve been shooting with very high speed film (that is, film with a very high ISO that is particularly photosensitive). Regular film most likely won’t be affected. Having said that, if you have photos on film that are absolutely critical to keep, you should probably try to have them processed before you get on a plane.
Let’s Put It All in Perspective
The main reason you shouldn’t worry about your electronics being damaged by airport scanners is that they’ll actually be exposed to more background radiation while in-flight than they’ll receive while passing through the scanner.
The Earth is constantly bathed in all kinds of radiation, most of which comes from the sun. The atmosphere does a great job of soaking most of it up, but the higher your altitude, the more radiation is around you.
So when you’re flying at 36,000 feet from New York to Los Angeles, you — and your gadgets — will receive the same amount of radiation as you would get from having two chest X-rays done. This is not a dangerous amount of radiation, but it does put things into perspective.
Have you ever had any electronics damaged in an airport security scanner? Find out whether TSA are allowed to take your phone.
Image Credit: Milkovasa via Shutterstock