The feasibility of Random Forests, one of machine learning methods was examined for the classification of radioactive waste drums. It was carried out using 954 γ-ray spectra of drums which were already classified to natural or reprocessed uranium. After 300 spectra were selected at random to reassemble training datasets, the percentages of correct classification by Random Forests were evaluated with another 654 spectra. When the counts of spectra were reprocessed as the difference of their logarithm, Random Forests accurately classified 654 drums.
“Zuiki” is the stem of a taro plant containing natural radioactive potassium-40. Several zuiki stems were peeled, dried, and micronized; then, the compression and formation method was used to make ten disk-shaped sources. These sources were measured as to their weight, thickness, diameter, and radiation count (using a GM-survey meter). The counted radiation was mainly attributed to β-rays from 40K. The averages (SD’s) of the weight, thickness, diameter, and radiation count were 15.1(0.03) g, 9.98(0.1) mm, 35.2(0.01) mm and 163.4(10.5) cpm, respectively. The usability of the sources for educational purposes was examined in three tests on the dependence of the radiation count versus time, distance, and shielding. Furthermore, the statistical fluctuation of the radiation counts was examined by making 50 measurements. It was concluded that the zuiki radiation sources were useful for demonstrating the three principles of radiation protection and the statistical fluctuation of radiation counts.
A survey of personal dose equivalent for children using optically stimulated luminescent dosemeters has been carried out in the southern Miyagi Prefecture. The survey results for approximately one year from April or May 2013 are summarised in this report. The survey covered Marumori-cho, Shiroishi, Kakuda, and Oogawara-cho. The difference in the exposure dose among areas was not seen. No one who received annual doses in excess of 1 mSv was observed for 99 children, who had kept well wearing the dosemeter for the whole year. Maximum annual dose was evaluated to be 1.10 mSv, including the external radiation from natural radiation. Findings of indoor and outdoor staying time (home and school) for children were also reported. As for Kakuda and Oogawara-cho, school children stay at the inside of their houses and school 20.8 h a day in a total, so nursery children do 20.5 h. This results are much the same as those obtained for Marumori-cho and Shiroishi children in the first report.
Radiation doses in air at 7 points in Saitama Prefecture were measured by thermoluminescence dosimeter from 2008 to 2013. Annual radiation doses at 7 points in 2008 and 2009 were 0.40～0.69 mGy/y and 0.40～0.68 mGy/y, respectively. These values were similar to those before 2007. However, annual radiation doses in air at all points, except 1 point where the measurement place was changed, increased after 2010. And the value in 2011 was the highest. It was thought that the cause of radiation doses increase was Fukushima Dai-ichi Nuclear Power Plant Accident occurred on Mar. 11, 2011.
The Higgs Boson was discovered at LHC (Large Hadron Collider) in 2012 and Theorists proposed BEH mechanize won the Novel Prize of Physics in 2013. Why the Higgs boson is so important? The Higgs boson is not ordinary elementary particles such as electron or photon, (composite matter or mediate force). The Higgs boson is a clear evidence that our vacuum is fulfilled with a strange filed with weak charge. This filed works as “the origin of mass” and “origin of evolution of our Universe”. Spontaneous change of the field makes phase transition of our Universe, In this article, I introduce “how to produce and detect the Higgs boson?” and also give the short introduction of Supersymmetry, which is the next main target of LHC.