Been long time away from Britain...makes me forget many simple words. For instance, this morning I could not recall what to say about a thing to stop water from running away from a bath tub. Cap? No. Shut? NO, No.
It is a plug! My Longman dictionary says "He pulled out the plug and let the water drain away" as an exmaple... My god, I should rather say "I pulled out the plug and let my memory drain away from my brain."
Perhaps, I should start writing something in English regularly here again so as to plug in my brain.
Tuesday, October 18, 2011
Friday, October 14, 2011
High radiation reading in Tokyo
At first, I could not believe it. I mean the radiation reading of "2.7 micro sievert per hour (uSv/h)" in the middle of Tokyo. This is because even in the city of Fukushima (about 50km away from the exploded nuclear plant) the radiation level (in air) is far less than 2 uSv/h.
The day before yesterday (12/Oct in JST), there was a report that a resident in Tsurumaki, Setagaya District, Tokyo claimed that she found a "hotspot" (a locally radiation contaminated area) with her Geiger Muller counter in the middle of the rich residential area in Tokyo. The "Borough" council had been quite reluctant to confirm it for long, but finally they did it. With a more accurate NaI scintillation counter, the council found the radiation level in the hotspot was more than 2.7 uSv/h! It was 3.5 uSv/h in fact. This number is much higher than the one in the peripheral of the exclusion zone... Tokyo is more than 250km away from the Fukushima No.1 nuclear power plant. It is hard to believe that such a place is more contaminated by radioactive Ce-137 than the city of Fukushima.
I went to the hotspot by myself in the morning to measure by myself. Simply because I could not believe the measurement done by others. The area is close to Baji-koen (a park where a horse riding competition was held in the Tokyo Olympic Games in 1960s'), which means that it is the area for rich and super rich people. Checking the place of the hotspot in Google Streetview, it is facing a large house with a big garage for multiple cars. I can see at least a Mercedes and a BMW in the picture.
I know quite a lot of people may be in the place, so I decided to drive through the place to "spy" at first. It was about 10 o'clock in the morning. Cloudy. After going down the road from the Baji-koen along the moderate down slope, I entered a narrow street sandwitched by big and nice houses. Checked a kindergarten I saw in the google, which meant the place is quite close. Then, I could see a bunch of people gathering in the street. Some of them parked their cars along this narrow street. Several motorbikes were parked in the pedestrian road. TV crews with a large videocamera. The people from the council wearing uniform with a NaI detector. Housewives living nearby. Various kinds of people were there. The park I planned to measure, which is next to the hotspot was already occupied by such many people. So, I gave up and run through the place.
From this place, Baji-koen is just 5min away by car. If the area is contaminated uniformly, Baji-koen should be also heavily contaminated. If not, the hotspot is quite local and something must be there. With a 10mins measurement, I recorded 20 data in Baji-koen. Then, took the average. The result is 0.14 uSv/h. My GM counter has a tendency to overestimate. A corrected value should be about 0.10 uSv/h. Before the Fukushima accident, I guess the natural radioactivity level in this area is around 0.05 uSv/h. This means the area is surely contaminated (mainly by Ce-137 and Ce-134), but the contamination level is not so severe. People living in many European cities such as Madrid, Moscow and Zurich have higher doses than this in their everyday lives.
Late in the evening on that day, there was a new report about this Setagaya hotspot. The cause of the high radioactivity comes from the house next to the street. The house is empty, but with a permission from the owner, the borough council investigated the house and found an old wooden box under the ground floor. Opening the box, they found several glass tubes containing some material. Pointing a NaI scintillator to the tubes, the detector read 30 uSv/h! It is the source of the radioactivity. Removing this box from the house, the environmental radioactive level dropped sharply down. The material was identified to be Ra-226, which was used to flash fluorescence/luminescence painting until 60 years ago. The owner of the house is a widow of a man who died 10 years ago, and she does not know why the box and the material was in her house, which were built about 50-60 years ago.
This incident was very entertaining. I enjoyed indeed. A kind of Sherlock Holmes type story, if the reason for the presence of Ra-226 is known.
The day before yesterday (12/Oct in JST), there was a report that a resident in Tsurumaki, Setagaya District, Tokyo claimed that she found a "hotspot" (a locally radiation contaminated area) with her Geiger Muller counter in the middle of the rich residential area in Tokyo. The "Borough" council had been quite reluctant to confirm it for long, but finally they did it. With a more accurate NaI scintillation counter, the council found the radiation level in the hotspot was more than 2.7 uSv/h! It was 3.5 uSv/h in fact. This number is much higher than the one in the peripheral of the exclusion zone... Tokyo is more than 250km away from the Fukushima No.1 nuclear power plant. It is hard to believe that such a place is more contaminated by radioactive Ce-137 than the city of Fukushima.
I went to the hotspot by myself in the morning to measure by myself. Simply because I could not believe the measurement done by others. The area is close to Baji-koen (a park where a horse riding competition was held in the Tokyo Olympic Games in 1960s'), which means that it is the area for rich and super rich people. Checking the place of the hotspot in Google Streetview, it is facing a large house with a big garage for multiple cars. I can see at least a Mercedes and a BMW in the picture.
I know quite a lot of people may be in the place, so I decided to drive through the place to "spy" at first. It was about 10 o'clock in the morning. Cloudy. After going down the road from the Baji-koen along the moderate down slope, I entered a narrow street sandwitched by big and nice houses. Checked a kindergarten I saw in the google, which meant the place is quite close. Then, I could see a bunch of people gathering in the street. Some of them parked their cars along this narrow street. Several motorbikes were parked in the pedestrian road. TV crews with a large videocamera. The people from the council wearing uniform with a NaI detector. Housewives living nearby. Various kinds of people were there. The park I planned to measure, which is next to the hotspot was already occupied by such many people. So, I gave up and run through the place.
From this place, Baji-koen is just 5min away by car. If the area is contaminated uniformly, Baji-koen should be also heavily contaminated. If not, the hotspot is quite local and something must be there. With a 10mins measurement, I recorded 20 data in Baji-koen. Then, took the average. The result is 0.14 uSv/h. My GM counter has a tendency to overestimate. A corrected value should be about 0.10 uSv/h. Before the Fukushima accident, I guess the natural radioactivity level in this area is around 0.05 uSv/h. This means the area is surely contaminated (mainly by Ce-137 and Ce-134), but the contamination level is not so severe. People living in many European cities such as Madrid, Moscow and Zurich have higher doses than this in their everyday lives.
Late in the evening on that day, there was a new report about this Setagaya hotspot. The cause of the high radioactivity comes from the house next to the street. The house is empty, but with a permission from the owner, the borough council investigated the house and found an old wooden box under the ground floor. Opening the box, they found several glass tubes containing some material. Pointing a NaI scintillator to the tubes, the detector read 30 uSv/h! It is the source of the radioactivity. Removing this box from the house, the environmental radioactive level dropped sharply down. The material was identified to be Ra-226, which was used to flash fluorescence/luminescence painting until 60 years ago. The owner of the house is a widow of a man who died 10 years ago, and she does not know why the box and the material was in her house, which were built about 50-60 years ago.
This incident was very entertaining. I enjoyed indeed. A kind of Sherlock Holmes type story, if the reason for the presence of Ra-226 is known.
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