Interview by Photographic Museum of Humanity

 Autoradiograph was interviewed by Simon Hall in PMH (Photographic Museum of Humanity) that is introducing contemporary art photography on internet. You can see how the autoradiographs were taken so far. It will be a guide to autoradiography for future photographers in countries where nuclear disaster would unfortunately happend.


 Thanks Simon Hall for interviewing and writing the admirable article.

All text is below.

In the years following the 2011 Fukushima nuclear disaster, photographer Masamichi Kagaya has been exploring the invisible yet deadly radioactive material that remains hidden in animals, plants and everyday objects inside the Exclusion Zone along Japan’s eastern coast. In collaboration with Dr Satoshi Mori, a professor from the University of Tokyo, the Japanese artist has produced a stunning series of autoradiographs that present unique visual evidence of the longevity of radioactive decay. Kagaya spoke to PMH about his work, offering detailed insights into the processes by which these extraordinary images are created.

PMH – Your series Autoradiographs explores the invisible effects of nuclear disaster. When did you develop an interest in the subjects of nuclear power and invisible radiation?

MK – We traditionally see radiographic images in a hospital environment, yet I thought it would be interesting to make image of radiation. I was inspired after seeing a radiographic image in a book about Chernobyl that was taken from a human lung.

Whether in Tokyo, in Fukushima Prefecture, or even standing in front of the nuclear reactor buildings whose cores melted down – and that were severely damaged by hydrogen explosions – we are unaware of the presence of radiation: it is too small to see; it cannot be heard; and it is odorless. Therefore, despite living in regions contaminated with radioactive particles, to this day, we are not consciously aware of the radiation. Using NaI(TI) scintillation detectors and germanium semiconductor detectors, the amount of radioactive contamination in soil, food, and water is measured in units called Becquerels (Bq). Radioactivity is further measured in Sieverts (Sv), which is an index of the effects of radioactive levels in the air, exposure doses, etc. on the body. Nevertheless, from such values, we cannot know how the radioactive particles are distributed or where they are concentrating in our cities, lakes, forests, and in living creatures. These values do not enable us to “see” the radioactivity. Thus, I believe that the radioactive contamination has to be perceived visibly and with the cooperation of Satoshi Mori, Professor emeritus, Tokyo University, I am using autoradiography to make radioactive contamination visible.

PMH – What is an autoradiograph? Can you tell us more about the process involved and how these striking visual depictions of radiation are constructed?

MK – The radiographic images were created by a method called “autoradiography.” Major universities and research facilities in Japan and throughout the world have autoradiography equipment, which is commonly used in biological, biochemical, and microbiological research to quickly view, with high sensitivity, the distribution of radioactive substances in a sample. These images are frequently used in research papers and in conference presentations. The radiation-sensitive imaging plate was developed in 1987 by Fuji Film Industries and Kasei Optics is approximately 100 to 1000 times more sensitive than x-ray film.

The imaging process involves placing a radioactive sample on the imaging plate for a given period, after which the imaging plate is read by a device called a BAS. The contrast of the read image is carefully adjusted, whereby the distribution of radioactive substances gradually becomes apparent. Radiation emitted by radioactive particles appears as black portions in the radiographic image. The darker the portion is, the stronger the radioactive contamination. An autoradiographic image exhibits the same phenomenon as an x-ray image taken at a hospital, where bones, which block radiation, appear white and portions through which the radiation passes without being blocked appear black.

When viewing a radiographic image, one point to keep in mind is that since each image is individually adjusted for contrast, the images cannot be compared with one another to determine which indicates greater contamination. In this series of images, records concerning specimens indicate β radiation levels in both “cpm” measured using a survey meter in the sampling of each specimen and in “becquerels” (Bq/kg) obtained by a gerimanium semiconductor detector. Concerning the measurement value “cpm” of the survey meter, for example, radioactive contamination is determined for an area if a value twice the usual background level is detected. The background level where measurement by a survey meter was performed is 25 to 40 cpm. Further, as a reference for measurements in becquerels, naturally occurring radioactive potassium K40 is on the order of 33Bq/kg for white rice, 1600Bq/kg for dried kelp, and 66Bq/kg (dry weight, excluding water content: 165Bq/kg) for the human body. Therefore, when comparing the measured values with these reference values, I think that you will come to appreciate the extent to which the specimens on display have been contaminated by radioactive particles.

PMH – The objects you photographed were collected from the area surrounding Fukushima. How did you gain access to the Exclusion Zone? Tell us about your experiences working within such a hazardous environment?

MK – Photographers and journalists are now afforded permission to enter the restricted area from the town. It had been forbidden for a certain period, but today a select few people are allowed to go inside the Exclusion Zone.

The radiation levels are dangerously high even now, particularly in the forest. Everything looks completely normal however, because we cannot see the radiation at all. The abandoned area is vast; ghost towns and deserted villages only 250 – 300 km from Tokyo. The journalists have too all but deserted these regions; press photographers cannot capture images of radiation and journalists have nobody to question – there are no stories for them.

PMH – What is the general attitude towards nuclear power in Japan three years on from the disaster?

MK – It is surprising. 140,000 people were forced to evacuate from Fukushima Prefecture and the people of Tokyo were also subjected to small doses of radiation fallout. Yet the Japanese people seem to have forgotten about the restricted area, and the residents in Fukushima don’t bother wearing masks to protect themselves. Furthermore the government, in conjunction with an electric power company in Japan, has promised to reopen Fukushima. The citizens of Japan have just voted into power the party that stated they would resume operations at the plant.

PMH – Do you have any future plans for this project?

MK – Yes, I have a few ideas. I cannot say with any real certainty, but there are many samples that I have yet to touch. I think it is a critical time because the level of fluent radiation (soluble caesium) is decreasing in nature year after year. All radiation has a half-life and the decontamination is progressing in urban areas.

PMH – What messages do you hope to convey through this series?

MK – Although what I can do is limited, I have succeeded in recording the radioactivity by making the invisible radioactivity visible. The history of senseless nuclear accidents caused by the United States, the Soviet Union (Russia), and Japan still has the potential to repeat itself somewhere else in the world, but I hope that future generations will break this cycle. With this exhibition, it is my hope that future generations will leave behind our nuclear power dependent society and be free from the dangers of nuclear accidents and nuclear waste.


(Masamichi Kagaya)

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