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J-PARC News October 2025 (Issue#246)

■Press Release
(1) Amino Acids Evolved with Deuterium - Hydrogen Isotope "Deuterium" Creates UV-Resistant Amino Acids - (October 2)
In recent years, deuterated amino acids, in which the hydrogen atoms in amino acids are replaced with deuterium, are gaining attention.
In neutron experiments, deuteration of biological samples such as proteins and amino acids is an essential technique. In the pharmaceutical field as well, the development of deuterated compounds-known as deuterated drugs, which can reduce dosing frequency and side effects-has been steadily progressing.
However, conventional methods for amino acid deuteration have been costly and have faced challenges such as achieving high deuterium incorporation efficiency and separating optical isomers.
In this study, a direct hydrogen-deuterium exchange reaction using a platinum-group metal catalyst and 2-propanol was applied. This approach enabled efficient deuteration, including the side chains, for more than half of the amino acids that constitute proteins, and also established a technique for separating their optical isomers.
Furthermore, it was found that the deuterated form of tryptophan, a precursor of neurotransmitters, was found to be more resistant to degradation under ultraviolet light.
This new method provides a foundation for the stable supply of deuterated amino acids that are difficult to obtain commercially. In the future, this technology is expected to contribute to the development of UV-resistant materials and more advanced pharmaceutical products.
For more details (Japanese only), please visit the J-PARC website.
https://j-parc.jp/c/press-release/2025/10/02001618.html

(2) Revealing Interfacial Structures with Neutrons - "Strong Yet Removable" An Eco-Friendly Smart Adhesive - (October 6)
Adhesion is a fundamental technology that supports a wide range of industries and is indispensable in daily life. However, conventional adhesives are often "strong but not removable," making recycling and component replacement difficult. Adhesion based on molecular recognition via host-guest complexes (a "key-and-keyhole" mechanism) has attracted attention, but the mechanism that enables repeated attaching and detaching has not been fully understood.
In this study, researchers developed a novel molecular adhesive material that enables easy detachment upon external stimuli-while maintaining strong adhesion-by controlling the formation of host-guest complexes at polymer interfaces. Using neutron reflectometry with the SOFIA reflectometer at the Materials and Life Science Experimental Facility (MLF), the nanoscale interfacial structure of the adhesive was visualized. This allowed the team to clarify the origin of an apparently contradictory phenomenon: complex formation suppresses molecular diffusion while simultaneously strengthening adhesion.
The adhesive technology developed in this research is expected to contribute to a resource-circulating society by enabling on-demand debonding and repeated reuse. It may help improve manufacturing yield, enhance recycling efficiency, and reduce waste.
For more details (Japanese only), please visit the J-PARC website.
https://j-parc.jp/c/press-release/2025/10/06001619.html

■J-PARC Hello Science "Creating Ion Beams - The H^⁻ Ion Source" (September 26)
Dr. SHINTO Katsuhiro from the Accelerator Division introduced the ion source, which serves as the starting point for the proton beam used at J-PARC.
At J-PARC, more than 2.2 quadrillion protons per second must be stably delivered to the experimental facilities. The beam, however, does not begin as protons.
Instead, it starts as H^- ions-hydrogen atoms (one proton plus one electron) with an additional electron attached.
To efficiently produce H^- ions, hydrogen gas is turned into a plasma, and the ions are generated on a cesium-adsorbed electrode surface in the ion source chamber. Dr. SHINTO explained the principles and techniques involved in this process.
A life-size model of the ion source, created using a 3D printer, was displayed at the venue.
Many visitors were surprised that J-PARC's world-class high-intensity proton beam originates from such a compact device-small enough to be carried by hand.

■The 10th Humanities-Science Integration Symposium - Exploring History with Quantum Beams - New Horizons of Interdisciplinary Research Woven by Accelerators(October 10-11)
The 10th Humanities-Science Integration Symposium was held in the Lecture Hall of the Japan Gallery at the National Museum of Nature and Science (Ueno Main Building).
This symposium brings together researchers from the humanities and natural sciences who have been conducting cultural heritage studies using quantum beams-such as synchrotron radiation, neutrons, and muons-to explore new possibilities for interdisciplinary research.
The event is organized by the Institute of Materials Structure Science (IMSS) of KEK.
This year, the symposium welcomed 63 participants, and over the course of two days, 13 presentations were delivered on topics including traditional lacquerware and detector technologies, followed by lively discussions.
From the "Muon ni Kofun Club"-a collaborative project between J-PARC and Tokai Village-Dr. KUZUHA from Ibaraki University gave a presentation titled "Exploring the Interior of the Funatsuka No.2 Kofun with Elementary and Junior High School Students Using a Particle Detector," sharing the progress of their outreach activities and current measurement results.
Additionally, on the afternoon of Saturday the 11th, a public lecture was held for general audiences, attracting a total of 243 participants both onsite and online.
This year's program also featured speakers including an expert in traditional woodblock printing techniques and a researcher from The Cyprus Institute. The event introduced simultaneous interpretation for the first time, offering valuable insights into the current state of humanities-science integration research in Japan and abroad.

■J-PARC Photo Contest 2025 Held
The annual J-PARC Photo Contest marked its 12^th year this year. The Grand Prize was awarded to "Lover's Lane" by Dr. UOTA Masahiko of Accelerator Section V.
According to the judges' comments, "The tunnel-like composition and strong sense of depth draw viewers into the scene, making it a compelling work that captured the hearts of many judges."
A total of 12 prize-winning photographs-including the Grand Prize, Excellence Awards, and Honorable Mentions-will be featured in next year's J-PARC calendar and used as part of J-PARC's public relations activities.
Award-winning photos can be viewed here (J-PARC website):
https://www.j-parc.jp/c/en/public-relations/j-parc-photo-contest-2025.html

■Japan-Switzerland Muon and Neutron Technology Collaboration Workshop "BRIDGE 2025" (October 20-22)
A J-PARC workshop was held at the University of Tokyo and the J-PARC center. Twenty-seven researchers from Switzerland, mainly from the Paul Scherrer Institute (PSI), joined the event, bringing the total number of participants to 60. They engaged in exchanges on common technologies related to high-power proton accelerator facilities.
On October 21, the participants toured the MLF and the Hadron Experimental Facility, where experimental equipment and ongoing technical developments were introduced.
Furthermore, on October 23-24, early-career researchers and graduate students from both countries participated in the workshop gathered at the KEK Tsukuba Campus for an Early Career Research Event, providing an opportunity for networking and collaboration.

■J-PARC Outreach Lecture
(1) Sannomaru Elementary School, Mito City (September 30)
A special outreach class titled "Let's Take a Look at the Invisible Vacuum" was held, with Dr. KAMIYA Junichiro from the Accelerator Division serving as the lecturer.
The class was conducted as part of a "Parent-Child Interaction Activity" for fourth-grade students. Together with their parents sitting beside them, the children enjoyed learning about science by predicting what would happen to familiar objects-such as balloons and marshmallows-when placed in a vacuum.
At the end of the session, with the cooperation of the homeroom teacher, Dr. KAMIYA demonstrated a vacuum cannon. The moment a ping-pong ball pierced through a can with a loud bang, the room was filled with cheers of excitement.
In the post-event survey, students commented, "I want to learn more!" and "I want to try doing experiments myself using familiar things!" showing that the class successfully sparked their curiosity and interest in science.
It is hoped that this outreach class will inspire the students to discover the wonders of science hidden in everyday life and further nurture their curiosity for learning.

(2) National Institute of Technology, Sendai College (October 10)
At Sendai College, Dr. OTANI Masashi from the Accelerator Division gave a lecture titled "How Accelerators Reveal the Microscopic World."
In his talk, Dr. OTANI explained the principles of accelerators and introduced their wide-ranging applications in fields such as industry and medicine, as well as the latest developments in accelerator technology.
The lecture was attended by about 20 participants.

(3) Kujigawa San-iku Elementary School (October 14)
A science class titled "What Is the Universe Made Of? - The Mystery of Light -" for elementary school students from first to sixth grade was conducted by Dr. SHIBAZAKI Chie from the Materials and Life Science Division. During the session, Dr. SHIBAZAKI introduced the nature of light through quizzes such as "Can you touch light?" and "What is light made of?", as well as experiments using the three primary colors of light. She explained the wave properties of light in a way that was easy for children to understand.
After the lecture, the students enjoyed making their own kaleidoscopes. Looking through the kaleidoscopes, they were fascinated by the sparkling rainbow world created by light.
One student commented, "This is exactly the kind of science story I wanted to hear!"

■Muon ni Kofun Club - Installation Site for "History and Future Detector No.2" Decided (September 21, Funatsuka No.2 Kofun, Tokai Village)
Under the clear autumn sky, fifteen participants conducted a field survey to determine the best location for installing the second "History and Future Detector," which has been under development for the past six months since last autumn.
The survey began at the History and Future Exchange Center. There, Dr. FUJII from J-PARC explained the key points to consider when selecting an installation site.
Curator Dr. HAYASHI then presented the mission for the day: based on the location of the first detector, the possible sites for Detector No.2 had already been narrowed down to two, and participants were to evaluate which of two locations would be more suitable.
Next, the group moved to Funatsuka No.2 Kofun. Dr. KAZUHA from Ibaraki University explained the current analysis results, and Dr. OSAKI from Ibaraki University discussed the estimated location of the stone chamber.
Keeping these points in mind, participants walked around the mound and its surroundings, checking details that could not be understood from diagrams alone. Each group then discussed the candidate installation sites.
In the end, all groups independently selected the same location. Dr. FUJII supported this choice as well, and the installation site for Detector No.2 was officially decided.

■J-PARC Sanpo-michi :Experiences Offered by J-PARC
As part of the Energy-Up Project at the Nuclear Science Research Institute, a Mölkky tournament was held, with 57 participants forming 13 teams from J-PARC.
Mölkky is a game in which players throw a wooden stick at twelve numbered wooden pins, scoring points based on either the number of pins knocked down, or the numbers written on them. It is accessible to people of all ages, requiring very little physical strength or athletic ability-perfect for anyone who simply wants to enjoy the competition. Because the rules are simple, some teams even joined the event without any prior practice.
Once the matches began, however, everyone's expression turned serious, and players gripped the throwing stick with focused intent. Despite unusually hot weather for early October, the sun sat low even during the lunch break, casting faint shadows of the pins across the lawn.
The pleasant sound of the stick striking the pins echoed under the clear autumn sky. With a 20-minute time limit for each match, players simply stood at the designated spot and threw when it was their turn, rarely breaking a sweat. Even so, once you try the game, you quickly discover its depth-planning the order of target pins, adjusting throwing styles, and refining strategies. After the tournament ended, some teams were already discussing tactics for next time.