01 August 2011

Gamma Radiation during Flight between Schiphol Amsterdam - Tokyo Narita

Radiation level at sea level in Tokyo is currently 0.09 uSv/h which is similar to the pre-March 11 level. At higher altitudes, however, radiation levels are much larger due to cosmic radiation. To see the impact of altitude on radiation levels, we measured the in-flight gamma radiation dose rates aboard a KLM plane flying from Amsterdam Schiphol Airport to Tokyo Narita Airport.

Measurement Conditions
  • Date: July 27, 2011
  • Flight: KL861, AMS-NRT
  • Seat: 12A
  • Flight Duration: 11h00m
  • Maximum Altitude: 33,000ft
  • Route: Netherlands, Sweden, South of Nova Zembla, Jakutsk, Chabarovsk, Niigata, Narita
  • Measurement Device: Polimaster PM1610
  • Type of Radiation Measured: gamma
  • Measurement Interval: 10m
Measurements
The graph below shows the dose rates measured. The vertical axis shows dose rate (uSv/h) and the horizontal axis time (hh:mm).

The total dose during the flight was 25 uSv. The flight started at 0:50 and ended at 12:10. Soon after taking off, radiation levels started to rise to 2 uSv/h. Three distinct radiation levels were recorded, each indicating a different altitude during the flight. A peak value of 3.1 uSv/h was reached close to Nova Zembla which was the most northern position during the flight. When the plane navigated southwards, we saw radiation levels gradually decreasing. Because incoming cosmic radiation particles are deflected by the Earth's magnetic field, the intensity of in-flight radiation is a function of altitude. In general, radiation shielding by the geomagnetic field is greatest at the equator and decreases as one goes north or south.

The top dose rate measured during the flight was about 30 times higher than the current levels in Tokyo. Does this mean that flying is dangerous? No, the accumulated radiation dose per year for five round trip flights between Europe and Japan add sea-level exposure would be approximately 1 mSv. This is well below any internationally alarm threshold levels.



03 July 2011

Volunteering in Ishinomaki, Miyagi-ken

Ishinomaki, 50 km north-east of Sendai, is the worst hit city by the tsunami in terms of casualties and destroyed houses. On a population of 160,000 almost 6,000 people are reported dead or missing, and 28,000 houses are fully or partly destroyed.

End of June 2011, I volunteered a week in Ishinomaki helping with cleaning and other relief work. The volunteering organizations, like the Peace Boat NPO, have setup an excellent and impressive infrastructure. Many volunteers I met have quit their jobs and moved to the tsunami hit regions for help. The volunteering center HQ runs from the Ishinomaki Senshu University Campus that also provides free camping facilities and basic sanitary facilities. Once you register as a volunteer, you are enrolled into an insurance scheme.

The volunteering HQ gathers needs from local residents. Volunteers are grouped and dispatched to locations. The first day, I worked in a group to remove sludge from gardens, houses and shops. In the late afternoon, we were asked to help searching for a 400kg safes. After some digging, we fortunately found it and could pull it on a mini-van. The 80 year old owner was very happy and offered us presents which we kindly refused.

After one day, I decided to join another relief work group called 'Amore Ishinomaki'. This group is lead by Yutaro - a Japanese body painter who went in March 2011 to the Sendai region by bicycle from Tokyo to start rescue work. His group works in a different way than the larger NPOs. In several districts in Ishinomaki City, one assigned local resident is responsible for prioritizing the works. Every morning, the group of volunteers goes to the house of this resident to get instructions and pick up tools. Our local 'mama-san' even prepared a delicious lunch for our group.

The district where I worked is located about 1km from the sea side. Most of the houses are two stories of which the ground floor was completely destroyed. Residents often live on the second floor but are unable to do the cleaning by themselves.











In our team we had three professional carpenters who removed the damaged walls, floors and kitchens. Water levels had been up to the ceiling of the first floor of the house. After opening the floors and walls, we could take the mud from the basement. A tough job to remove the 20cm thick slime layer.











The Jieitai, the Japanese Self-Defense Forces, have setup public baths for local residents and volunteers. After a day of hard work, one can refresh in these free bathing facilities. Usually the water comes from a nearby river which is filtered and sanitized. We were lucky that onsen water from Yamagata Prefecture arrived that day.

More than three months after 311, the needs are still high while the number of volunteers has dramatically dropped. The volunteer center in Ishinomaki has announced on their web site that individual volunteers from outside the region cannot register anymore. Smaller organizations like Amore Ishinomaki will continue their relief work, though.

For those we want to volunteer, please check the volunteering organization's web site for the latest updates. Here is a map of Ishinomaki with the main spots described in this post.

Stay tuned.