Online Radiation Monitoring Station

geiger-counter-build

This is a Geiger counter which charts its readings on a webpage. [Radu Motisan] put a lot of time into the build and it shows. This thing is packed with features and the hardware choices were the best combinations found through several iterations of development.

In addition to radiation levels the sensor unit takes several other measurements. These include temperature, humidity, luminosity, and barometric pressure. All of the sensor data is monitored and gathered by an ATmega168 which can be charted on a webpage with the help of an ENC28J60 Ethernet chip. The collection and display of this data is detailed at the post linked above.

For those interested in the hardware development, [Radu] published many updates along the way. These are available in his forums posts, as well as his build log. He doesn’t have any videos of his recent work, but way back in May he did publish a clip (found after the break) which shows the testing of different Geiger tubes.

 

10 thoughts on “Online Radiation Monitoring Station

  1. Yes, the tube is made in USSR, but the SBM-19 is one of the best Geiger tubes currently available. Some are still available online, but are rather expensive. I’m also considering adding a few more such tubes in parallel for increased sensitivity. Would help identify even smaller variations.

    1. Even in a “neutral” environment there could be changes in the reading, for example from radon washout after rain, or due to increased cosmic ray flux.

      Nevertheless, monitoring radiation with a geiger tube is one thing, interpreting the results is another. Geiger tubes only count the times “something” has ionized the gas in the tube, there is no way to tell what particle or ray at which energy caused a detection.

      If you depend on geiger tubes for gauging radiation, your measurements can be completely off. GM tubes are calibrated to give a certain amount of pulses per Sievert/Roentgen, but only for gamma rays of the specified nuclide, for example Co-60 or Cs-137.
      A standard metal wall GM tube will detect hard beta radiation best, but has low efficiency for gamma rays. If you want a relatively cheap all-round radiation detector, get a GM tube with a mica window (for example the Russian SBT-11A) which detects gamma, (soft) betas and alpha radiation.
      If you want superior gamma detection, get a scintillation detector. These are more expensive, but you’ll be surprised at the sensivity. For example, my geiger counter does not detect a lot outside of my box which holds spark gaps with Cs-137 and a radium clock, but my scintillation detector gets really active.

  2. Also I’ve since determined that adding a Zobel network to the tube consisting of two 10M resistors in series and a 0.1uF 400V poly capacitor seems to calm down temperamental counters when exposed to intense RF fields.
    Worked for mine anyway and it now doesen’t shriek like a banshee near my laptop.

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