66% or better

Geigers on a plane

[Thomas] took a Geiger counter he built on a plane. Why? Because he can, much to the chagrin of airport security.

[Thomas]‘ Geiger counter is built around an old Russian SBT-10A detector containing ten separate Geiger tubes. This tube was connected to a circuit containing a LiPo battery, a few high-voltage components, and an audio jack connected to the tubes themselves. When alpha, beta, or gamma radiation hits one of the Geiger tubes, an enormous click is sent to the audio jack and into the microphone jack of a small netbook.

Right after boarding a plane in Dublin, [Thomas] booted up his computer, started recording in Audacity, plugged in his Geiger counter, and stored his experiment safely in the overhead compartment. After landing in Prague a few hours later, [Thomas] saved the 247 MB .WAV file and began working on a way to convert clicks in an audio track into usable data.

The audio output on the Geiger counter overloaded the mic input on his netbook, making ‘event detection’ very easy with a small C app. After plotting all the data (seen above), [Thomas] had a complete record of the radiation on his 2-hour flight.

Because there was far less atmosphere to absorb cosmic radiation, [Thomas]‘ radiation dose was 9.1 microsieverts. Much more than at sea level, but nothing even air crews need to worry about.

Comments

  1. Love this. Scientists are my fave.

  2. Luke Weston says:

    A bit of not-that-well-known trivia:

    Professional airline crews and pilots have by far the highest occupational ionising radiation dose of any people employed in any industry of any kind.

    Yes, higher than nuclear engineers and nuclear power workers medical radiologists and industrial radiologists nuclear medicine technologists and physicists and anyone else in any kind of industry.

    Even though people working in those kinds of industries deal with health physics and radiation safety controls and personal dosimetry and RWPs and all that sort of stuff all the time, in most cases those sort of health physics controls are completely non existent for airline crews.

  3. Treehouse Projects says:

    Awesome, awesome experiment. I absolutely love stuff like this.

  4. Oh gosh, imagine losing the file after the flight *shudder*. I would create a script to record and save at intervals, although with my luck that would crash more than audacity would.

    • Shaddack says:

      Very valid comment. The decision to do the experiment was done on the way to Ireland, so the datalogging had to be done with only the gear I carried with me. Hence its highly improvised nature and taking the risk you described.

  5. NewCommentor1283 says:

    the name of the article reminds me of snakes…

    but seriously, great data!

  6. kris says:

    How did you get it past airport security?

  7. Anonymous coward says:

    “[Thomas] took a Geiger counter he built on a plane.”

    Why did he build it on a plane to begin with? ;)

  8. macona says:

    If you use scintillation detectors instead of geiger tubes you can get meaningful data. Not so much with geigers. You will just get CPM.

    There are a couple software solutions for dealing with the audio,

    PRA will handle gamma spectrscopy on a PC, http://www.physics.usyd.edu.au/~marek/pra/index.html

    Geiger Bot will do a similar thing on a iOS device: http://itunes.apple.com/us/app/geiger-bot/id427728355?mt=8

    I have not had much luck with the software. Pulse shaping is very important. I have been told it has a lot to do with the ADCs in the sound cards. They are capacitive based and not the optimal kind for this signal.

    • Shaddack says:

      I’d say that CPM counts as meaningful data. (Of course, scintillation detector gives way more meaningful data, you’re right with that.)

      Thought re AC (instead of DC) coupling of the detector via a soundcard… what about superimposing a higher-frequency signal (use the detector signal to amplitude-modulate a carrier with suitably high frequency way above what the baseband signal bandwidth, then demodulate it in software once digitized? There are some USB soundcards that go up to 192 kHz samplerate at 24 bits stereo, that’s quite a lot of wiggle room for data acquisition.

      As of a scintillator-photomultiplier probe, I would not mind one. However, after Fuckupshima the prices of everything related to radiation sensing went through the ceiling like an SL-1 control rod. :( Even just a NaI:Tl crystal would be helpful, a drop of silicone oil can be used as a decent optical coupling.

      • macona says:

        Sure, CPM counts are good but you really dont get to know what you are getting hit with.

        I have a NaI(Tl) scintillator and PMT I put together. I have not gotten anything useful out of it with the PRA software. Last week I got a NIM Bin and some modules so I am hoping to clean up the signal and try it again.

        The pulses are very short coming out of a PMT. Higher bit depth does not help and an increased sample rate only helps so much. You are just stuck with the wrong ADC for the job.

        There is the Gamma Spectacular, a USB interface for scintillation and proportional counters. http://www.beejewel.com.au/research/Bee_Research/gamma_spectacular.html

    • Whatnot says:

      Why not some simple pre-processing if the signal is such an issue? Geez it’s like we are tech illiterate here.

      • macona says:

        You can process the signal externally, thats what NIM modules do. Discriminators, shapers, and the like. My experience taking a signal straight from a PMT on a Scintillator into a sound card has not been good. A lot of echoing due to the cheap ADC.

  9. steffen says:

    oh my god dont you know you have to turn off all electronic equipment for start and landing!!! oh my god oh my god oh my god you could have died!!!

    • mur1010 says:

      I think you are being silly here. Geiger counters can’t produce any kind of electromagnetic radiation that would interfer on the plane’s mechanics or radio system. Neither the netbook, ’cause it complies with the FCC rules.
      Actually I carry powered on equipment when I fly.

      The only equipments that can cause real bad interference on the mechanics or radios of a plane are cellphones, radio tranmitters and EMP. But because these kind of equipment are intended to generate electromagnetic radiation.

      And why a plane would crash because of this interference only when they are taking off or landing? This is just silly. So, no, they couldn’t have died.

      Anyway, interesting article HaD. I’m going to be a pilot so this is one interesting thing for me. I’ll try to carry radiation dosimeters every time I go to a plane from now =)

      • angus says:

        > why a plane would crash because of this interference only when they are taking off or landing?

        Because it’s easier to crash when you’re near the ground. That’s when most air crashes happen. If something went wrong with electronics/navigation/communication at higher altitude, they’d have more time to understand the problem and work around it.

    • draeath says:

      Lets be fair. I turned on my kindle once while it was laying on my radio’s antenna (yes, ON it.). I heard a little bit of digital noise for a short moment. Keeping in mind that signal strength decreases with the square of the distance traveled…

      I also had it in dual VFO mode, so it was (in that configuration) especially vulnerable to noise.

      Therefore anecdotal your chances of causing any meaningful interference: stupidly tiny

  10. harviecz says:

    Nice project! Right now i am working on recording my movements during sleep using PIR sensor to study ma sleeping habbits. I am going to use similar technique involving soundcard… Maybe i can reuse some of those scripts… But i think that i will rather make some script to detect events on the fly and store them using RRD tool or something similar…

  11. cde says:

    This title was deceiving. There was not one grotesque penis monster at all. (read: Giger on a plane)

  12. Destate9 says:

    “Right after boarding a plane in Dublin, [Thomas] booted up his computer…”

    Well of course he detected radiation, because someone was using electronics during the takeoff, the plane wasn’t able to initialize its energy shields. Because he didn’t shut down his devices, he endangered everyone on that plane by exposing them to mutating, tail-creating, hulkifying radiation!

    Am I the only one who pays attention to the in flight safety videos!?

  13. Jc says:

    Sorry to say you’re not entirely accurate here. As a practicing EMC engineer in the aviation industry I can site a few examples that demonstrate this is not the case. Recently a fault on a 737 affecting the navigation equipment was traced to a hand held gps receiver someone was using in the cabin. Aerospace EMC rules are a lot tighter than FCC rules so the fact that that something complies wit a commercial requirement means nothing. As for the plane crashing instruments giving false readings can cause air crashes, if your altimeter told you you were at 1000ft when you were only at 900 in the dark and fog whilst coming in to land… Have a look at the EMC Journal’s Banana Skins Column for more nasty EMC stories.

    mur1010 says:
    July 29, 2012 at 4:05 pm
    I think you are being silly here. Geiger counters can’t produce any kind of electromagnetic radiation that would interfer on the plane’s mechanics or radio system. Neither the netbook, ’cause it complies with the FCC rules.
    Actually I carry powered on equipment when I fly.

    The only equipments that can cause real bad interference on the mechanics or radios of a plane are cellphones, radio tranmitters and EMP. But because these kind of equipment are intended to generate electromagnetic radiation.

    And why a plane would crash because of this interference only when they are taking off or landing? This is just silly. So, no, they couldn’t have died.

    Anyway, interesting article HaD. I’m going to be a pilot so this is one interesting thing for me. I’ll try to carry radiation dosimeters every time I go to a plane from now =)

    Reply Report comment
    angus says:
    July 29, 2012 at 4:44 pm
    > why a plane would crash because of this interference only when they are taking off or landing?

    Because it’s easier to crash when you’re near the ground. That’s when most air crashes happen. If something went wrong with electronics/navigation/communication at higher altitude, they’d have more time to understand the problem and work around it.

  14. LiveProtoplasm says:

    That’s quite the little “don’t worry, be happy” (effectively pro-nuke) zinger the editor slipped in there on the last line; 9 uS is not something that “air crews need[n't] worry about.” Flying professionally does carry a statistically increased cancer risk.
    What level of risk is considered “safe” may be a matter of individual perception, but there is no level of radiation exposure that is risk-free. A great deal of PR and misinformation is prevalent (“blah, blah…small leak…but no risk to the public”), encouraged and promoted by the nuclear establishment. Don’t fall for it (especially if you are, or might be, pregnant.)

    • Shaddack says:

      Given the lack of conclusive proof of the impact of the low doses, and therefore the validity of dose-response rate at the minimal-to-low doses, I wouldn’t worry so much. The linear no-threshold model is no gospel, as the fearmongers want us all to believe to push the anti-nuke agenda. If it would be so dangerous, its impact wouldn’t be cowardly hiding deep within the statistical error. There may be quite well a threshold for harmful dose/dose rates, or maybe even the radiation hormesis effect.

      There is a statistically significant increase of probability of certain cancers in flight crews. The studies so far however aren’t clear how much of it is because of cosmic rays, or lifestyle factors associated with flying (e.g. irregular circadian rhytm, having fewer children (for breast cancer), increased exposition to sun during leisure time (melanoma), etc.); so the jury is still out even here. See e.g. here:
      http://oem.bmj.com/content/60/11/805.full

      The small leaks from nuclear plants can quite well be of lower total magnitude than the continuing radioisotope contamination in the vicinity of coal power plants. In deaths per gigawatt-hour nuclear power fares pretty well in comparison with other energy sources.

      And even with the linear no-threshold model the risk at low exposures may be nonzero – but in comparison with other risks of life it doesn’t seem to be worth worrying about.

  15. You can also make sensors using pieces of Indiglo EL sheet biased with a small DC voltage of about 30V and placed over a CdS photoresistor or other photosensor.
    Best would be a large area silicon diode, what happens here is that the EL glows every time it breaks down and acts a bit like a scintillator.

    I found this out by accident when handling a used piece of EL and put it over an americium source, which made it flash brightly where the source was as its capacitance discharged.
    An alternative is to use a piece of X-ray cassette film and a CdS sensor biased at about 20V with a large series resistor, although these saturate easily they are fairly sensitive.

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