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Government Lab Uses Smartphones To Measure Gamma Ray Exposure

Posted by samzenpus on from the hulk-phone-is-strongest-there-is dept.

KentuckyFC writes "Back in 2008, Slashdot reported that researchers were developing ways of turning cellphones into radiation detectors. Since then a few apps have even appeared that claim to do this. However, convincing evidence that they work as advertised is hard to come by. Now government researchers at Idaho National Labs have created their own app that uses an ordinary smartphone as a gamma ray detector, put it through its paces in the lab and published the results. The pixels in smartphone cameras can detect gamma rays in the same way as they pick up visible light. So when the lens is covered, the image should reveal evidence of gamma ray exposure once other noise has been removed, such as that from heat and current leakage. These guys have tested several types of Android smartphone with a variety of gamma ray sources at various different doses. The researchers say the phones give a reasonable measure of radiation dose, can detect the direction of source (by comparing the measurements from the front and back cameras) and can even measure the energy of the gamma rays by measuring the length of the tracks that appear in the image. While the results do not match the quality of bespoke detectors, that may not matter since in many circumstances cellphones are likely to be the only sensors that are available. That could be useful for emergency services, air travelers wanting to monitor their extra radiation dose on routes over the arctic and people who live in areas with a higher than average background radiation level."

23 of 105 comments (clear)

  1. My iPhone is getting Angry! by jellomizer · · Score: 4, Funny

    You don't want my iPhone getting Angry!

    --
    If something is so important that you feel the need to post it on the internet... It probably isn't that important.
    1. Re:My iPhone is getting Angry! by amRadioHed · · Score: 2

      I don't think there was ever any question that phones generate radiation, that is what the antennas are for. But this is for gamma rays, if your phone is generating any of them then something is horribly wrong.

      --
      We hope your rules and wisdom choke you / Now we are one in everlasting peace
  2. Two words by cold+fjord · · Score: 2

    HULK SMASH!!

    Does sound like a neat idea. I'm hoping there won't be much call for it outside of labs though. I'm not a big fan of excessive radiation.

    --
    much of left-wing thought is a kind of playing with fire by people who don't even know that fire is hot - George Orwell
    1. Re:Two words by i+kan+reed · · Score: 2

      You don't like the sun?

    2. Re:Two words by cold+fjord · · Score: 2

      From what I hear gamma radiation come from more sources than just the sun, sometimes in dangerous dose rates.

      But I'm intrigued, are you suggesting that solar radiation never poses a risk under any circumstances?

      --
      much of left-wing thought is a kind of playing with fire by people who don't even know that fire is hot - George Orwell
    3. Re:Two words by NatasRevol · · Score: 2

      Holy shit that's bad reading on your part

      GGP - "I'm not a big fan of excessive radiation"
      GP - "You don't like the sun?"
      You - "are you suggesting that solar radiation never poses a risk under any circumstances?"
      Me - WTF are you reading?

      --
      There are two types of people in the world: Those who crave closure
  3. Digital camera elements by i+kan+reed · · Score: 3, Interesting

    I've always wondered why we can't do simple infrared or ultraviolet examinations of things with our smart phones.

    I have a sneaky suspicion it's because not all clothing is opaque in those spectra, but I like neat science toys, and wish my phone was a little more tricorderish.

    1. Re:Digital camera elements by cold+fjord · · Score: 2

      The sensing elements used in the cameras are designed for their purpose. They will generally have a limited range of sensitivity in terms of the wavelengths they detect. Different materials and sensor element designs may be needed depending on the wavelength, required sensitivity, and other aspects of the intended use and environment. Something that works well for infrared may not work well for UV detection and measurement. Doing it all uncooled adds other challenges.

      --
      much of left-wing thought is a kind of playing with fire by people who don't even know that fire is hot - George Orwell
    2. Re:Digital camera elements by Lehk228 · · Score: 3, Interesting

      infrared and ultraviolet are intentionally excluded from cameras with filters so that the image recorded looks like it should, I suppose filters could be applied on a per pixel basis in order to make a 5 or more element R,G,B,IR,UV sensor, but the cost would be .... considerable

      --
      Snowden and Manning are heroes.
    3. Re:Digital camera elements by i+kan+reed · · Score: 2

      Would it really be that much more than an RGB filter?

    4. Re:Digital camera elements by Bite+The+Pillow · · Score: 2

      People use cameras to take pictures of visible light, so the demand for other spectra just isn't there. The simple digital devices have a filter film that can be removed, or replaced for night vision. They are not optimized for night vision so sensitivity is an issue. But it works.
      Depending on where you got your camera parts, they may have a filter, or its possible to do math instead. But a film is cheaper as long as it stays in place
      If you have one, replace it with thin black paper or other things.
      As for why, smartphones are not designed to be user serviceable. But if you're a geek, anything's serviceable.

    5. Re:Digital camera elements by Immerman · · Score: 4, Informative

      Actually most digital cameras are far more sensitive to infrared than to visible light - they actually come equipped standard with infrared blocking filters so that the visible spectrum isn't totally drowned out, and they *still* can usually see the wimpy blinking light on your IR remote. I think they're usually less sensitive to UV though.

      --
      --- Most topics have many sides worth arguing, allow me to take one opposite you.
    6. Re:Digital camera elements by Obfuscant · · Score: 2

      A filter removes a portion of something. You filter out things. Phone cameras don't use an RGB filter.

      Actually, they do. The standard single-chip image color image sensor uses what is called a Bayer filter array of red, green, and blue color filters in a regular pattern, one filter per pixel. From this data, a color image is reconstructed by combining the color data from that pixel with the colors from the neighboring pixels. The dirty secret is that the resolution of a "megapixel" camera is thus much less because a nine by nine array of pixels is used to create the color data for each color output pixel.

      Color sensitivity is often reported in the datasheet for the sensor. This is a datasheet for a typical CMOS sensor, and the color sensitivity is shown on page 11. The individual sensitivity is due to the filters, the MONO data is for the sensor sans filter. CCD spectral curves are quite similar. The Sony ICX285AQ is an example. If you compare data sheets, you'll notice that the ICX285AL is identical to the AQ with the exception of the color filters, and the AL version is the monochrome sensor.

      It would be interesting and not that expensive to create a different color filter pattern on the sensor to include IR and UV filters, but the use would be limited. Those who want IR images typically use the monochrome sensor and external IR pass filters, and UV is usually excluded by normal users by the use of a skylight or other UV cut filter. The dyes in the RGB filters are sensitive to the UV and will decompose over time, changing the color capability of the camera.

    7. Re:Digital camera elements by hubie · · Score: 3, Insightful

      Digital cameras are very insensitive to the IR. Silicon, which is what all commercial camera sensors are made of, loses its sensitivity around 1000 nm, so photons with a longer wavelength than that generally pass through undetected (they are most sensitive around 600-ish nm, which is something like orange light). On the other hand, if you look at the spectrum of light coming from the Sun, you get the most photons around that same 600 nm wavelength (how's that for coincidence?), but you also still have a whole lot of photons flying around with wavelengths of 1000 nm and less. Camera makers put IR-blocking filters on because the optics for the cameras are optimized for visible wavelengths, so IR wavelengths will not come to a nice focus. These IR wavelengths add image blur. Some people want to pop their IR filters off because it will make their camera more sensitive, which technically is true, but you'll make your pictures look blurry unless you do something else (i.e., filters) to restrict the wavelengths of light through your optics.

      You also have to be careful when you talk about the IR that these cameras can detect. What you're really talking about is very deep red, or the first parts of the NIR (near infrared) region. Most people, when they hear IR, think heat signatures, but that is not what you're dealing with here. The thermal IR is much longer wavelengths, and you'll never see that with a silicon-based camera. In fact, pure silicon is very useful as a window material for IR sensors because it is very transparent to photons at those wavelengths.

    8. Re:Digital camera elements by hubie · · Score: 2

      I agree that most lenses will have no problem focusing 1000 nm. The problem is trying to focus across that whole wavelength range. Decent multi-element lenses are designed to operate best in the visible, and you will not get the same kind of performance near the NIR. I learned the hard way years ago after spending the effort to optimize the focus of a camera (using a decent-quality Schneider lens), I then put a NIR long-pass filter on and, until I finally had that forehead-slapping "duh" moment", I couldn't figure out how my focus got so crappy. Fortunately, the fix for me was to just re-focus the lens and the image looked fine. As you say, a crappy lens is a crappy lens, so the effect will be less noticeable with cheaper lenses.

      Another thing working against the cell phone type camera as an IR detector is that the reason silicon is not very sensitive out in those wavelengths is that most photons with those wavelengths pass through and don't interact in the material. The way to make it more sensitive towards the IR is to have a thick detector substrate; however, especially with cell phone cameras, the design is to make them as thin as possible to cut down on detector noise.

  4. It's not a nuclear power plant by h00manist · · Score: 2

    Read again. It doesn't generate radiation. It's not a nuclear power plant.

    Though if someone writes an app to turn the phone into a safe nuclear power plant it might be popular.

    --
    Build your own energy sources from scratch. http://otherpower.com/
  5. Additional /. Story On CellRad by iinventstuff · · Score: 2

    Here's some more info from a prior /. posting on CellRad

    http://mobile.slashdot.org/story/13/05/17/2218226/cell-phones-as-a-radiological-dirty-bomb-detection-network

  6. SciFi movie swishing doors = no sex? by h00manist · · Score: 2

    I am not sure the lack of a connection between swooshing doors and sexual attraction is clear. Can you elaborate.

    --
    Build your own energy sources from scratch. http://otherpower.com/
  7. Re:Headline is ambiguous by Immerman · · Score: 3, Funny

    Really?
    Student uses yardstick to measure classroom. Dang, we gotta watch out for all those yardsticks creating extra distance.

    --
    --- Most topics have many sides worth arguing, allow me to take one opposite you.
  8. App (Android and iOS) by bammmmm · · Score: 2

    here is an app from 2011 doing exactly that: video (there are a few): http://www.youtube.com/watch?v=GAWQ-YT8BvE android: https://play.google.com/store/apps/details?id=com.rdklein.radioactivity&hl=en iOS: https://itunes.apple.com/us/app/radioactivitycounter/id464004677?mt=8

  9. A few apps exist already by mspohr · · Score: 4, Informative

    TFA states that the "may" release the app but there are already a few gamma radiation detectors on the Play Store for Android such as these:
    https://play.google.com/store/apps/details?id=eu.camdetector.radiationalarm&hl=en
    https://play.google.com/store/apps/details?id=com.rdklein.radioactivity&hl=en
    Basically you cover the lens with black tape to block light but of course gamma radiation can get through. The apps need to be calibrated to your individual phone since random noise in the sensor can give false readings. The apps provide a method to do that.
    As the article states... the best radiation detector is the one you have with you.

    --
    I don't read your sig. Why are you reading mine?
    1. Re:A few apps exist already by mspohr · · Score: 3, Informative

      Wikipedia has some good references here:
      "Shielding from gamma rays requires large amounts of mass, in contrast to alpha particles which can be blocked by paper or skin, and beta particles which can be shielded by foil. Gamma rays are better absorbed by materials with high atomic numbers and high density, although neither effect is important compared to the total mass per area in the path of the gamma ray.
      The higher the energy of the gamma rays, the thicker the shielding made from the same shielding material is required. Materials for shielding gamma rays are typically measured by the thickness required to reduce the intensity of the gamma rays by one half (the half value layer or HVL). For example gamma rays that require 1 cm (0.4) of lead to reduce their intensity by 50% will also have their intensity reduced in half by 4.1 cm of granite rock, 6 cm (2½) of concrete, or 9 cm (3½) of packed soil. "
      So, gamma rays can pass through black tape, plastic and glass lenses without much difficulty.

      --
      I don't read your sig. Why are you reading mine?
  10. Not for airline altitudes by celticryan · · Score: 2

    The majority of the dose at airline altitudes is from neutrons (55%), with only a small component from photons (gammas are photons) - 5%. This is, of course, on average. I do not think anywhere in the preprint they claim to be able to measure anything but photons. Therefore, a cell phone will not do a great job of monitoring your radiation dose at airline altitudes.

    However, there is a tool being developed by NASA which does a real-time calculation of your radiation dose along an airline trajectory. Check out NAIRAS

    References:
    Cosmic Radiation @ skybrary
    NAIRAS aircraft radiation model development, dose climatology, and initial validation