Member #656653

Member Since: March 3, 2015

Country: United States

  • I feel compelled to add to this blog since there seems to be a lot of confusion about this sensor and several of the negative reviews are not justified in my opinion.

    This product (Pocket Geiger Radiation Sensor - Type 5) is built around the X100-7 ionizing radiation detector from First Sensor AG. The X100-7 is a high-quality and very stable solid state PIN diode detector with a large surface area. Similar versions of this detector have been used in several of NASA's x-ray telescopes.

    The great thing about this detector is that its response does not depend on a carefully-regulated high voltage potential the way that a Gieger-Muller tube does. On the other hand, the X100-7 has an approximately 2 minute response time, so radiation detection IS NOT INSTANTANEOUS as it is with Gieger-Muller tubes. This later fact leads to many misunderstandings. This is not the sensor you want to use if you are prospecting for uranium because the response time is too slow. But if you want to accurately measure how much cesium-137 has contaminated the environment after a reactor accident, for example, then this is exactly the sensor you want. That's why thousands of these same sensors are in use in Japan today.

    This sensor can detect gamma radiation and, if the included copper shield plates are removed, beta radiation. It cannot detect alpha radiation, since alpha is easily blocked by something as thin as a sheet of paper and it cannot penetrate the thin copper foil that is integral to the sensor. The X100-7 is quite sensitive; I have used mine to detect the decay of naturally occurring potassium-40 in bananas.

No public wish lists :(