Perform your own accuracy test regularly to check the accuracy of the measuring instrument

At the “data site for everyone”, we emphasize the accuracy (accuracy) of the data we publish.
Therefore, in order to confirm the measurement accuracy of each participating measurement room in advance, we carry out an independently established accuracy test.

For each measuring instrument, measure 4 types of standard brown rice samples, which are priced at approximately 3 to 100 Bq / kg in fine, low, medium and high concentrations.
The measurement result is compared with the attenuation correction value of the reference brown rice sample on the measurement date to see if it falls within the evaluation range.
If all four types of samples fall within the range, it is judged that there is sufficient accuracy, and it becomes possible to participate in everyone's data site.

In addition, measurement rooms share information about measurement technology, such as sharing experiences, to improve measurement accuracy, and if necessary, perform cross checks etc. Each measurement room further improves measurement technology and knowledge, and measurement By maintaining accuracy, I would like to back up to be a reliable citizen measurement room.

This site will be a familiar tool that can be used by any one person to easily check the radioactivity measurement, and will be a bridge between people's radioactivity measurement stations and people in various places, and the activities of each measurement station will be boosted I hope that it will be one opportunity to

"Standard brown rice sample" kit

Exchange of information between test stations and sample exchange (cross check)

On the mailing list, we exchange information on a daily basis, share and verify technical questions, and share activities. The measuring instrument may have features or specific defects depending on the manufacturer or model. Such information is known only after it has been shared and accumulated in the data site of everyone where many measurement rooms gather. We have been working on the road carrying data, such as working with measuring instrument manufacturers for software improvement. Also, sometimes we check the measurement accuracy of each other's measuring instruments through cross-checking, etc. where the same sample is circulated and measured in multiple measurement rooms. When the General Assembly is held once a year, it is used as a forum for active exchange of information, such as technical exchanges and discussions.

Confirmation after data upgrade

The individual data are from the measurement room where the data was measured and entered into the data site. The secretariat also regularly checks if there are any errors in the data even after the site upgrade, and strives to detect input errors etc.

Efforts to raise measurement accuracy in soil measurement

In the soil, there is a problem that it is difficult to distinguish it from the measurement data of natural nuclides (bismuth, lead etc.), especially in the measurement of soils with low concentration of cesium and abundant natural nuclides There was a problem of difficulty depending on
In addition, in the case of high-concentration cesium samples, there is the problem of diffusion and exposure due to the movement of cesium, so there is a problem that it is necessary to perform accurate measurement with a small amount rather than a large amount.

Therefore, in addition to the accuracy check using the previous standard brown rice, a subsidy from the Takagi Jinsaburo Citizen Science Foundation was obtained in 2016, and a verification project was conducted. As a result, it has been found that there is something like "the habit" of measurement result calculation by software.
As a result of this research, it has become possible to correct the measurement data so far and publish it as data closer to the actual value.
* In the measurement results (details) of the soil project, it is the correction data that is described as “corrected”.
* It is not a correction of a large value so that the color of the map changes.