Sad, off-topic: Martin Perl died: a Stanford Nobel prize winner for the tau lepton discovery...
If you detect this pattern, then FBI is trying to irradiate you by lethal radiation. You may only find out if NSA hasn't hacked your smartphone's camera, however. ;-) More seriously, the app detects both cosmic rays and radioactivity from the environment.
If you have an Android device, you are invited to download an app by Justin Vandenbroucke who is junior faculty in Wisconsin:
Univ. at Madison: press releaseYou may need to change your Android settings to allow the installation of APK packages from outside Google Play – you must think twice whether you trust apps linked to from a wisc.edu page.
Their astroparticle center about DECO
App part 1 (data logger), app part 2 (DECO app)
Both parts of the app are smaller than 1 megabyte.
Your Android camera normally detects visible light but it's sensitive to other things, too. In particular, if you cover it so that it should be black, it is still not black.
Instead, it will still detect some noise and that includes the cosmic rays. And the app, after it records the signal each second or so, may analyze what it sees by methods that are not too different from the methods employed by astroparticle experimenters.
The author of the app hopes that this app or its future cousins will energize some kind of "citizen science". You may imagine millions of people who are detecting cosmic rays all over the Earth. You could use such Android users instead of detectors in particle accelerators, too. You save $1 billion and just ask the 3,000 ATLAS employees with their Android smartphones to stand somewhere at the collision point. ;-)
A typical screenshot of the DECO app.
If a new Higgs boson or a supersymmetric particle decides to escape from CERN, not die in time, and create a signal in your Android device, let me know! ;-) Just kidding.
The iOS version is work in progress.
P.S.: the second part of the DECO app just crash for me all the time, won't start on my tablet. At least, there may be some Geiger-Müller counters on the Play Store and perhaps some of them are even serious. ;-) I suspect that this app shows rubbish numbers unless you actually connect a special gadget using the microphone cable.