High-Energy Astrophysics Researcher
Professor Jun Kataoka
Department of Applied Physics, School of Advanced Science and Engineering, Faculty of Science and Engineering
Making radiation common and safe
The Center for Research Strategy spoke with Professor Kataoka, who has made remarkable achievements in cutting-edge research in astrophysics, medical care, and in wake of the nuclear power plant accident, the environment.
(Interview date: December 21, 2016)
Applications in the environmental field
It is not that there were no cameras in the world to visualize gamma rays until now. Something that each manufacturer made existed, but they were used for specific and static purposes, such as monitoring nuclear facilities. These were heavy and had to be kept in place for 30 minutes to an hour to take one picture. Then, the Fukushima Daiichi Nuclear Power Plant accident occurred, causing radiation to spread across vast areas. In other words, radiation visualization became necessary at a more general level, but the previously mentioned devices were incapable to meet such need.
Hence, immediately after the accident, my team, in collaboration with Hamamatsu Photonics K. K., worked on making a more compact and sensitive camera with the ability to shoot radiation distribution images near real time. We began developing a compact Compton camera, taking advantage of the experience in space science as well as the medical field. The first product we made was roughly 1.9kg and about 15cm in size, visualizing gamma-ray distribution by combining visible images taken with a fisheye lens and images from a gamma-ray camera on a computer. When moving the gamma-ray source, the camera was sensitive enough to identify the position within tens of seconds after the movement.
Reducing weight and using drones
Though developing a high-performance compact camera was satisfying, there was still a problem here. About 70% of Fukushima Prefecture is a forested area. When the outlook of decontamination work in urban areas became clear and the discussion turned to how the remaining forest areas should be dealt with, our team initially thought that we could take the camera into the forest and shoot with a standing tripod. However, when actually visiting the site, it was quite tough to walk about the mountain paths even with a roughly 2kg weight, realizing the inefficiency in the task.
An idea I conceived then was to utilize a drone. Even commercially available drones can lift about 5kg. Our camera’s greatest strengths, its compactness and high sensitivity, were put to good use here. We installed a laptop computer and a Compton camera on a drone (DJI-manufactured S1000+: 4.4 kg) and photographed the area for about 10 minutes from a height of approximately 15m – 20m. In doing so, we were able to capture the distribution of radionuclides in direct-line range of around 70m in one shot. The images sent from the camera to the ground in real time showed where the hot spots were.
Since coming up with this setup, we have actually been conducting surveys at Namie Town in Fukushima Prefecture about once every two months. Though they are still trial flights, I would like to provide data useful for decontamination work. (For details, please refer to the news on September 16, 2016 “Imaging scattered radionuclides distribution in gamma-ray shooting, using a drone”
Pride as a researcher
The way my research results contribute to society, especially in space science, is not something that can be seen directly other than excite astronomy fans, making it difficult to assert. However, I believe that work, such as unraveling the profound mysteries of the universe, is related to the development of pure science, and in turn, to national prestige and dignity. Moreover, I take pride in developing various devices, intended for providing new knowledge to people all over the world 10 to 20 years from now. I strongly insist on this point as a researcher.
On the other hand, my feelings of wanting to give back to the world in a slightly shorter span are reflected in the practical application of my research to the medical and environmental fields. I would be happy if the technologies that we cultivated in different fields are put to practical use by manufacturers, even partially, and indirectly become more available in the world. Rather than having our technologies and innovations become decorations in laboratory shelves, firstly materializing them is important. That is why I never close off work just within the University, but actively collaborate with different universities, companies and organizations.
Mutual enhancement through stimulation
I only see advantages when it comes to cooperating with external research institutions and corporations. Because my previous laboratory did not have contracts with companies nor carry out research jointly, I was initially worried that it would hinder my research, but that was not the case at all. Companies we are currently working with have flexibility and the attitude of wanting to present good innovations to the world.
Not only limited to companies, I believe external cooperation is beneficial for also consciously positioning ourselves in the world. In that sense, participation in international conferences is also a task to objectively confirm your current progress. For example, even with the development of the Compton camera, we felt that we had made a breakthrough achievement at the time. However, when attending presentations at international conferences, I can feel the gradual rise of the quality of research in the world. This motivates us to make even greater innovations so as not to be defeated, thus increasing the importance of originality. Besides, giving good feedback for mutual enhancement is very valuable.
Research tends to become self-righteous, which should not be the case. Making output while always being aware of where you stand is important, and claiming that you were able to do something on your own is meaningless if the world does not recognize it. On the other hand, everyone will regard your innovations highly if you make something great. Producing something uncertain and rushed to achieve quick results is no good. Because I am a researcher, I cannot put out fabricated results, and it does not make sense to do so. On the other hand, if you work too slowly, there will be a number of times when other researchers will have already analyzed and presented the data which you had planned to publish a paper on, perhaps 2 to 3 days before your publication. In such cases, accepting your loss and how you will switch gears to think about the next thing will become important.
Undiscovered treasures scattered about
As I often tell my students in the laboratory, being open-minded is what I value most when taking on research. For example, there are some students who only attend related sessions when participating in academic conferences. At times, some students only intently pay attention to presentations by their own seniors whom they regularly meet. I tell such students to attend presentations of unrelated fields for the next session if they have time. Precious discoveries lie in seemingly unrelated places. Genuinely new ideas emerge from places that nobody expects, so I believe that looking at completely different fields is essential for researchers.
Moreover, it is quite common that technologies difficult to use in certain fields are used often in others. If you look around other places, it will inspire you with new ideas and save you time from making extra detours. Having many interests as possible as well as talents to draw upon in an emergency are very helpful.
As a Waseda University researcher
I have been to various universities, but the physics and applied physics departments at Waseda University offer an excellent environment to do research. Each and every professor is independent yet loosely connected. The academic and research levels are high overall, and because there are many professors invited as lecturers to academic societies, I am influenced to work hard assiduously while conducting research in a great atmosphere.
In addition, students at Waseda University have a broad spectrum, just like light, and there are diverse students ranging from short to long wavelengths. As for me, I feel pleasure in bringing them together and leading the way so that we can produce good results. Moreover, there are many students who are sociable. Even students doing top level research in Japan, moreover the world, are, in a good way, not too proud but humble and very friendly. This is also a big selling point. Also, I feel that many students agree with my approach of having a go without becoming defensive in whatever you do. For me as well, being exposed to new ideas through interactions with students and combining them with my own experiences and know-how to sublimate towards new themes get research done in an ideal environment.
On the other hand, I do not necessarily want all my students to become a researcher, which is a limited and specialized profession. For example, if you are interested in medical equipment, you could get a job at a related manufacturer. There will be greater significance in a sense that you will feel much closer to society and the industry, a different appeal from research and development. Whatever path they decide to follow, I would like my students to find their own beliefs and convictions to demonstrate their strengths there. At first, it is okay to follow someone. However, speaking from my point of view, you must exhibit your originality to compete in the world after having gained experience to some extent. I would like students to have unique assets or skills that only they possess, even if it is just one, and compete along their own path.
Leading the future in radiation imaging
Waseda University’s standing in space science is extremely high, even from a global perspective. As you may know, we have ranked top 100 globally in this field before, so there are skills and potential. It is necessary to produce constant results from now on. To that end, increasing the University’s academic output, including myself, becomes fundamental.
Whether Japan is a radiation-exposed country or not, it is difficult for the word “radiation” to be accepted, and there is an atmosphere where establishing advanced medical treatments such as radiation therapy is difficult compared to other countries. Therefore, I would like to contribute my research to the world in a way that radiation becomes more common and used as something safe. Imaging technology can appeal to the general public in a straightforward manner, so I would be glad to cooperate as a part of this aim. It is my dream to see the devices I develop becomes useful in many aspects of society, whether it be space, medical care, or the environment.
Professor Kataoka graduated from the University of Tokyo’s Faculty of Science in 1995 and its Graduate School of Science in 2000 (Doctor of Science). He became an assistant at Tokyo Institute of Technology’s Graduate School of Science and Engineering in 2001 and later appointed as assistant professor in 2007. From 2009, he served as associate professor in the Graduate School of Advanced Science and Engineering at Waseda Research Institute for Science and Engineering. He has held his current position as professor of physics and applied physics since 2014.
Website: Kataoka Laboratory
- Inverse Compton X-ray Emissions from TeV Blazar Mrk421 during a Historical Low-flux State Observed with NuSTAR (The Astrophysical Journal, 2016, in press)
- Compton cameras for visualization of radioactive isotopes (KOGAKU,The Optical Society in Japan, 2016, in press)
- Global Structure of Isothermal Diffuse X-ray Emission along the Fermi Bubbles (The Astrophysical Journal, 2015, vol.807, p.77 (13 pages))
- Recent progress of MPPC-based scintillation detectors in high precision X-ray and gamma-ray imaging
(NIM-A, 2015, vol.784, p.248)
- Suzaku Observations of the Diffuse X-ray Emission across the Fermi Bubbles’ Edges
(The Astrophysical Journal, 2013, vol.779, p.57)
- Other publications available here
Awards and recognition:
2001 Cosmic-Ray Physics Achievement Award
2004 The Astronomical Society of Japan Young Astronomer Award
2009 NASA Group Achievement Award
2012 The Young Scientist’s Prize from the Minister of Education, Culture, Sports, Science and Technology
2013 Publications of the Astronomical Society of Japan Excellent Paper Award (Co-authored)
2014 Waseda Research Award (High-Impact Publication)
2016 Waseda University’s Core Researcher of the Next Generation