Safecasting Fukushima Live Report

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Today we are Safecasting from Tokyo to Minami Soma, Fukushima. Driving today are Joe and Kalin with self in the back seat handling communications (ahem)


Today’s goal is to measure a hotspot we recently found on our map in Minami Soma, take soil samples, cover a few roads not covered yet, and meet with volunteers in Koriyama in the evening. So far we have had heavy traffic due to rain and Golden Week holiday rush, and we hope to achieve as much as possible. Total distance 500km back and forth.

On board we have a lot of measurement equipment – 8 bGeigies, 14 various geiger counters and 1 spectrometer (SAM940 3″). We also have tools for taking soil samples.

Two of the bGeigies are for volunteers in Aizu and Koriyama. One of the volunteers is the Fukushima Kodomo no Momorokai volunteer group (Fukushima Save the Kids group), which is another grass roots volunteer group nation wide that has done much to educate and measure radiation in local communities. The 2 bGeigies are the now legendary bGeigie Mini’s with Ninja’s for remote monitoring. Most of the 3,000,000 measurement have been done with the Mini’s. Accidentally, today is also the exact birthdate of the bGeigie Mini system, which was built after the first 3 bGeigies, that were using a PC to control the sensors outside the car. The Mini eliminated the PC by using a Freakduino and special shield and made the bGeigie ready for crowd use.

Another 5 bGeigies are for Minami Soma city where we have received request from their city . These are the new bGeigie+, which have rechargeable battery and have a USB interface for charging and easy file reading.


For the bGeigie+ we developed a new Arduino shield that supports the new functionality. Together with Sugimura-san, Robin and Joe we have been busy working on many improvements to the bGeigie+ over the past months to improve reliability and manufactureablity. In our stress tests this week we were able to get between 10-11 hour non-stop operation on a fully charged system without any disruption in measurement (location, radiation, time). Tests included mounting the bGeigies on our bicycles to see how the system performs under extreme vibration and impact. To ensure we are able to recover from occasional system hangs, Akiba helped us to enable a function that will restart the system in case it stops responding. We hope with the deployment of the 5 bGeigie+ in Minami Soma we will see if the improvements have been effective and identify further opportunities for improvement. And of course the bGeigie+ come with Ninja wireless monitors and rugged Pelican cases.

Another area we have made much progress is to provide better tools for quickly viewing and analyzing raw measurement logs. Lionel and Rob made a utility that allows a drive log file to be emailed and returns a map in PDF format with drive analysis. It also supports output in KML format and reports can be generated in Japanese or English. As it runs through email, it ensures that it can be used in environments where public access to internet is limited or custom software can;t be easily installed (e.g. corporate networks that are behind a firewall)

“Never leave home without a geiger” mom used to say 🙂

Today we have a good variety of geiger counters and scintilators. Of course many are the Medcom Inspector, the work horse for most measurements we do at Safecast. We use them exclusively in our bGeigies and for surface measurements. We also have a scintilator from Thermo, that allows for fast gamma measurement and hot spot identification. The yellow device is a Thermo B20 surface contamination and gamma dose rate geiger counter. The other is a Mazur Instruments PRM-8000 with a LND712 geiger tube and recording capabilities that Kalin brought along. It’s similar to the german Gamma scout. It’s not a looker but is a well engineered device.

The blue device on the right is the Ninja – it shows the radiation level the bGeigie is measuring outside the car. It can show multiple bGeigies output, and provides visual and audio signals in case of loss of GPS signal, high radiation levels, and device failure. Robin did a great job recently rewriting the interface and the Ninja is a whole lot more intuitive in use!



We just finished measuring the areas in Ibaraki we had not covered yet and are now en route to Minami Soma.

To be continued …