Update from Werner Tornow, who is working at KamLAND in Japan

Wednesday, March 23, 2011

Tuesday, March 22, 2011 - email update from Prof. Werner Tornow I arrived in Tokyo on Monday, March 14, three days after Friday's devastating earthquake and ensuing tsunami. During my 10 years plus travel to Japan I never went through immigration and customs at Tokyo-Narita airport as fast as this time, because there were only a handful of non-Japanese on my Delta flight from Atlanta. However, for the first time I had to wait much longer than usual to get on a bus to Tokyo's Haneda airport. Due to the rolling blackouts in Tokyo, train service is restricted and bus service is on high demand. Nevertheless, I made my connection to Toyama (located on the west side of the island, i.e., opposite side of Tokyo) and I arrived in the Japanese Alps at Mozumi (Gifu Prefecture) the same night. Mozumi is the little village where the control centers of the KamLAND and Superkamiokande (SK) detectors are located. Both the KamLAND and SK Collaborations have dormitories in Mozumi. On the next morning I was driven to the mine (a ~3 mile drive) where the KamLAND detector (our TUNL group built the so-called veto detector of KamLAND more than 10 years ago) is located at the center of a mountain with about 1 km overburden, and started my two-week KamLAND shift service as planned. Data-acquisition is of course done automatically, but there are other things the shifter has to do. Most parts of the detector (it's a 1 kilo-ton liquid scintillator viewed by about 2000 photomultiplier tubes and surrounded by our water-Cherencov veto detector) can be monitored from off-site and many features can be checked or changed remotely, but certain parts (some by law) have to be checked by person on a daily basis. This is basically the only reason to go into the mine, if everything is working normally. It takes about two hours to do these checks. In addition, important parameters are being recorded hourly. This is done remotely by the on-site shift person (me) and remotely by Japanese graduate students, post docs and faculty in Sendai and during the Japanese night by scientists in the U.S. (where it is daytime). Did I notice any difference compared to the Fall of 2010, when I was there the last time? Yes, there was hardly anyone in the KamLAND building at Mozumi. The scientists and graduate students normally stationed at Mozumi were busy transporting food and gasoline to Sendai, which was hard hit by the earthquake. Tohoku University in Sendai manages the KamLAND experiment. Therefore, all my Japanese KamLAND faculty colleagues are from Sendai. Luckily, they are all o.k., I was told. Most of Sendai is on high ground, therefore the tsunami has destroyed only small parts of the city. However, many buildings, including buildings on the University Campus are heavily damaged by the earthquake. Currently, the University is closed for students, but faculty and staff can enter certain buildings (with hard hat) until 5 p.m. Since Wednesday of last week (March 16) we have again email connection to the Tohoku University Research Center for Neutrino Science (RCNS) in Sendai, i.e., power has been restored and today, almost one week later we even had a video conference between KamLAND and RCNS. However there has been a real shortage of basic supplies in Sendai. Therefore, until two days ago, the Japanese KamLAND people here at Mozumi were still making those 7-hour (one-way) trips to Sendai to deliver food and gasoline. As a result, for many days, including the long weekend (Monday, March 21, was a holiday) I basically was the only KamLAND person on site. My U.S. KamLAND collaborators (there are about a total of 50 U.S. scientists in the KamLAND Collaboration) monitored the detector remotely in between my shifts, i.e., it allowed our Japanese colleagues to take care of their much more important business. Ironically, the main purpose of the KamLAND experiment was to study specific properties of so-called anti-neutrinos, which are produced in nuclear reactors. The 55 Japanese nuclear reactors have been a powerful source of anti-neutrinos and it was KamLAND that showed for the first time with high precision that neutrinos oscillate from one species to another, which is only possible if neutrinos have a finite mass. Because the neutrino oscillation experiments don't provide information on the actual neutrino or anti-neutrino mass, the KamLAND detector is scheduled to be converted into a double-beta decay detector during the coming months. Preparations have been underway for more than one year, and I wanted to contribute to this effort during my stay at KamLAND. Yesterday, Monday, just after returning from the mine, I was about to sit down in front of a computer in the KamLAND Control Center when the ground started shaking. It was one of those fairly weak earthquakes (4.7 magnitude with epicenter not far away from us) which became so common after the big one of March 11. Today, most of the Japanese KamLAND people reported back to work. Work continues as normal. They are not talking about the earthquake and the tsunami, and some of them are disappointed that the Japanese nuclear power industry doesn't seem to be in a position to get the damaged reactors at the Fukushima-Daiishi plant under control. A note on the rolling power outages in Tokyo: Due to historical reasons, the Japanese power system uses both 50 Hz and 60 Hz. 50 Hz is used in eastern Japan, including Tokyo, and 60 HZ is used in western Japan, where KamLAND is located. With some of its reactors shut down or destroyed, the Tokyo Electric Power Company is capable of generating about 30 GW, while the weekday demand is about 40 GW, therefore causing the rolling power outages. Western Japan's power companies have plenty of capacity to cover this 10 GW shortage. However, a frequency conversion is necessary. Unfortunately, the existing conversion facilities seem to be able to handle only about 1 GW. We here on the west side of Japan have no power problems, whatsoever. Do I feel safe?  Absolutely. A tsunami is not going to make it up the mountains. The region here has experienced many small, but never a really strong earthquake. It's too far away from north-eastern or south-eastern Japan. The distance argument also holds for the nuclear reactor crisis. In case something really bad is going to happen at the Fukushima-Daiischi nuclear power plant, we are here too far away, and it is more than unlikely that the wind will blow in our direction. In addition, as a nuclear physicist I understand the hazards associated with radiation and should be able to respond appropriately. Furthermore, considering my age, I am much more likely to die of other reasons than of an overexposure to radiation. It just takes too long for "even medium" radiation levels to do much harm to the human body. Of course, I saw Roger Wendell. On Sunday we shared a ride up to the mine, where he is working on SK.