J-PARC News September 2020 (Issue #185)

■ J-PARC Online Open House 2020 ~Visit J-PARC Online This Year!~ 0.png

October 7 (Wed) 12pm, our event website opens! 

In addition to The Kids' Corner, we have lots of fun contents such as videos of 7 facilities including one shown to the public for the first time. For details, please refer to following article. (


■ Letter of Appreciation to Kashiyama Industries, Ltd. and Suzuki Shokan Co., Ltd. for Contributing to the Development of Highly Durable T0 Chopper (September 11, J-PARC)

J-PARC Director Naohito Saito presented a letter of appreciation to Kashiyama Industries, Ltd. and Suzuki Shokan Co., Ltd. for the efforts they have given for the successful development of a new highly durable T0 chopper. Prior to the presentation, a lecture "Development of Highly Durable T0 Chopper" was given. Mitsutaka Nakamura, a sub-leader of the Neutron Science Section (an instrument scientist of BL01 4SEASONS) explained the development and required specifications of the T0 chopper, and Mr. Matsumi Iwane of Kashiyama Industries, Ltd. talked about the journey to the successful development on behalf of both companies. The Materials and Life Science Experimental Facility (MLF) uses a T0 chopper to block gamma rays and fast neutrons generated at the moment that the pulsed protons strike the target, which are major factors of the background events in neutron experiments. However, durability issues such as vibration and bearing damage were problems for the reliable operation at high speeds. In addition, there had been a strong request to prolong the maintenance cycle (for high durability) due to the high dose of radiation it receives for being near the neutron beam extraction port. In the development of the T0 chopper, the companies had to overcome various technical issues such as stable operation at 100Hz with an asymmetric rotor structure, increased bearing rigidity while maintaining high-speed performance, and a high-efficiency air-cooling system without cooling water. The T0 chopper was completed in two short years since the start of the development, meeting all the required specifications given by researchers. The companies received compliments from the participants. The T0 chopper has already been used at BL01 since December 2019, and J-PARC would like both companies’ continued support on MLF's research activities.


■ J-PARC Safety Day

Lecture by Dr. Rieko Hojo, National Institute of Occupational Safety and Health, Japan (JNIOSH) Held Online ~"Invitation to Occupational Behavior Analysis"~ (September 9, J-PARC)

The J-PARC Center has established a "Safety Day" in every May, recognizing the radioactive material leak incident in May 2013, as an important safety issue. This year, due to the spread of the novel coronavirus, the event was held on September 9 in a remote live format. In the opening, Naohito Saito, Director of the J-PARC Center, gave a greeting, followed by commendation of the J-PARC Center's "Good Practices of FY 2019." Among many good practices nominated according to various safety patrols, a total of six good practices were chosen for the four awards: the Most Frequent Good Practices Award (Neutron Instrumentation Section and Accelerator Section I), Safety Consideration Award (Neutron Instrumentation Section), Creativity Award (Nuclear Transmutation Division and Accelerator Section II), and Sanitation Consideration Award (regarding novel coronavirus infection prevention measures practiced by everyone working at J-PARC). The center director handed a certificate of commendation to each winner.

Following the award ceremony, Dr. Rieko Hojo of JNIOSH gave a lecture "Invitation to Occupational Behavior Analysis." She is a member of the Mechanical System Safety Research Group of JNIOSH, and has been studying "occupational behavior analysis" that applies the concept of behavior analysis (one of the specialized fields of psychology) to safe behavior in the industrial field. She began her lecture, stating, "Human behavior is classified into three categories: unconditioned response, conditioned response, and observational learning, and human behavior is maintained by its consequences." She gave fascinating talks about human behavior and actions under various environments and conditions using case studies.

In addition, in regard to the accident on May 23, 2013, a video “J-PARC Radioactive Material Leak Incident -Focusing on Scientific Aspects-" was screened. This video was recently created in order to communicate to the non-specialists about the incident with a focus on the scientific aspect in an easy-to-understand manner. Finally, Tetsuro Ishii, Deputy Director of Safety of the J-PARC Center, gave the closing remarks, and that completed the "Safety Day" event.


■ J-PARC Hello Science "It's Over When It Stops- Exploring the Movement of Proteins with Neutrons" (August 21, Tokai Industry and Information Plaza “iVil”)

Hello Science in August featured a lecture by Dr. Satoru Fujiwara of the National Institutes for Quantum and Radiological Science and Technology, Institute for Quantum Life Science. The theme was "What do neutrons contribute to life sciences." It began with a talk on self-proliferation of living organisms and the mechanism of virus infection/proliferation, followed by a lecture on proteins. The lecture explained that proteins are essential for all living organisms to live and have various functions. Also, in order for these functions to work well, proteins' movements (fluctuations) are critical. Then, he introduced quasielastic neutron scattering, which is a technique for observing these fluctuations. He added that J-PARC has the instruments called DNA and AMATERAS, which are suitable for measuring the fluctuations of the proteins. These instruments help researchers understand the functions of proteins based on the data of the energy exchange between neutrons and the proteins, that occur when the proteins are irradiated with neutrons. Many answered in the participant questionnaires that they were satisfied with the lecture, which is closely related to our bodies.


■ Sanpo-michi #2 ~Go for a stroll around J-PARC~

-J-PARC Health Checkup-

Every year, J-PARC suspends operation and has a long vacation from July to September, which is the time when Japan experiences the highest electricity demand every year.

However, J-PARC staff are not taking a vacation during that time. It’s time for summer maintenance work. Staff can enter only during this period because radiation is coming out from passages of proton beams in accelerators during operation.

Photos show maintenance crews taking measurements (with 0.01mm precision) of positions of acceleration cavities and electromagnets of Linac, which is the first accelerator. If a device in which the proton beams travel is not aligned precisely within 0.1 mm, the proton beams do not travel in a correct orbit.

This annual precision survey is necessary because buildings are ever so slowly deforming. If deformation is detected, it is fixed by applying a correction to a magnetic field with the electromagnet or by moving a position of a magnet.

Even with this adjustment, accelerator positions cannot be fully maintained. There is also periodic fluctuation. The buildings deform slowly over several months due to seasonal temperature variation, and the earth itself is distorted every day by the gravity of the moon as well. Although it is not easy to adjust the position according to those factors, position data of the accelerators show that if it is currently high tide or low tide.

While the J-PARC's accelerators are substantial devices, they are also very delicate devices.