First unit in Japan measures low background radioactivity

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The unit shipped to Japan finally went online yesterday. For now it is connected indoors. The unit measured an average of 0.12uSv/h in Timisoara, Romania during a few hours of tests.

Surprisingly the values dropped to 0.07uSv/h when the first measurements started at its current location, in Japan. The first half of the graph shows recordings from June, during its initial tests, while the second half contains the measurements from July, recorded in Japan.

Here are the values in CPM, as recorded by the SI-29BG Geiger tube contained in this detector, illustrating the same decreasing trend:

The integration was set to one hour, meaning that for each number plotted on the X axis, 60 distinct measurements recorded 1 minute apart were averaged to give a better indication on the real values. The unit’s other parameters indicates everything is functioning in normal parameters. Here is a chart showing the voltage on the Geiger tube, following a constant level of the preconfigured 380V:

And here is the internal temperature:

The real time data is available here. For those of you interested in getting one of these units to monitor the radiation levels in your area, remember there is one currently available on Ebay for a very low price, to cover just the materials used: http://www.ebay.com/itm/131253996906