Following the Fukushima nuclear disaster in March 11, 2011, a group of friends in the United States and Japan started a dialog to discuss what they could to help the friends and family in Japan. Since monitoring for radioactivity was very important following the disaster, the availability of Geiger counters was a critical issue. Seeing that conventional sources of Geiger counters sold out quickly after the disaster, the conversation turned to the possibility of building and distributing Geiger counter. People who had expertise in particular relevant areas were invited to join the conversation.
Work began to aggregate and display radiation readings on an online map. As readings began to come in and were added to the map, areas with no readings were noted and it became a priority to get Geiger counters into those areas.
An annual event in Japan for hardware hobbyists was converted into a conference on responses to the nuclear disaster following the Fukushima earthquake and tsunami. Some of the people working on the project met for the first time at the conference on April 1, 2012. One outcome of the conference was the design of a new Geiger counter which would come to be called bGeigi. It would incorporate a GPS which would allow it to be moved around to take radiation readings. It was decided that a organization would be created to focus on aggregating and displaying radiation data. The name Safecast was chosen for this new organization.
Safecast proceeded to obtain funding from Kickstarter and private individuals. Hundreds of volunteers were recruited and Safecast became the organization to publish more information on radiation levels in Japan than any other institution.
The main Geiger counter designed by Safecast and manufactured by International Medcom is called the Inspector Alert (IA). It is based around a 2” diameter pancake Geiger-Müller tube. This tube has excellent sensitivity for alpha, beta and gamma radiation. The IA is handheld and easy to use with a digital display. The units cost $700 each and forty have been built and deployed.
The CRM 100 has a design similar to the IA but it employs a smaller and cheaper Geiger-Müller tube called the LND 712. It is smaller, cheaper, less sensitive and takes a little longer to register than the 2” tube in the IA. It is the device primarily distributed to volunteers who want to take individual readings around their homes and neighborhoods. It costs $450 and thirty units have been built and deployed.
The bGeigie is basically a IA combined with a GPS and electronics which takes a reading every five seconds with a GPS tag and stores it to an SD care. The bGeigie is placed in a weatherproof box and attached to a car so it can be moved around and automatically take readings over a wide area. Wifi has been added to the most recent design to allow readings to be uploaded in real time. It costs $1000 and twenty five have been built and distributed.
The nGeigie has the 2” Geiger-Müller tube and is intended to be set up at a fixed location to take repeated readings. Wifi and wireless versions will be available as installation requirements dictate. Safecast is establishing a fixed sensor network based on the nGeigie. It costs $500 and twenty have been built and distributed.
The iGeigie is a design concept that is intended to work with a mobile device such as an iPhone. It is still in the prototype stage. When manufactured, it will cost $200.
The Safecast map displays over two million data points, primarily over Japan. There is a Fusion map that has been created which uses Google Fusion table to display data on Google maps. An Interpolation map has been create which attempts to uses shading to filling in the estimated radiation between collection points. An Aggregate Feed map combines and displays radiation data from the Japanese government, several non-governmental organization as well as Safecast submissions. Safecast Drive maps display individual maps for each measurement drive by a Safecast volunteer. Yahoo! Japan has built a Yahoo map that shows data from fixed location Safecast sensors. In addition to these maps, Yahoo also uses the same data as the Yahoo map to show graphs of radiation.
Safecast map:
