A ring for the circular economy
Mottainai is the Japanese phrase for “what a waste!” which environmentalists use to describe the needless discard of resources, food, or materials. In recent years, it has become a buzzword for the sustainability movement of Japan, but also on an international level. The Japanese culture has always given more weight to the benefit of society than to the individual compared to Western countries. As such, Japan’s new strive for sustainable technologies and materials is not surprising, given the technological leadership of the country in industry segments like electronics and material design. The new 3GeV synchrotron radiation facility is a consequence of that effort: Designed as “a low-cost brother” of the big SPring-8, one of the top 5 synchrotrons of the world located in the center of Japan, it strengthens the density of research infrastructure in the eastern part of the country. It reflects the high demand from Japanese companies to get more access to synchrotron radiation.
Synchrotrons are highly sophisticated vacuum facilities in which electrons are accelerated and guided on a large diameter circle to emit specific radiation. The 3GeV facility has a circumference of 349m. It focuses on the soft X-Ray spectrum which is very interesting to investigate organic functional materials, magnetic materials as well as carbon-based molecules for drug, food, and medical applications. These are the main materials and core technologies for a sustainable economy. For example, functional organic molecules, e.g., biodegradable plastics or novel solar cell materials, promise to enter the circular sustainable economy on a large scale. Furthermore, the research on magnetic spintronic devices aims to replace silicon-based chips by improving speed and energy efficiency. This tackles a major problem of the digitization era with an increasing share of IT systems in the world’s power consumption.
To create synchrotron radiation, an ultra-high vacuum inside a ring made of tubes needs to be established and maintained. Time-effective maintenance is an important factor for the 3GeV facility since the project aims to deliver synchrotron radiation to private industrial companies, usually working on tight project plans.
Comforting electrons on their train ride in the storage ring
As an expert in tailored vacuum valve solutions VAT, has already manufactured vacuum valves and components for the 3GeV-facility’s big brother, the SPring-8. One strategy in the management of large vacuum systems is to segment them into different vacuum zones by all-metal RF-sector valves. In case of leakage or maintenance requirements in one zone, the other zones can be held under vacuum, while only the leaking or maintained section can be vented and serviced. This solution also limits contamination by leakage through the penetration of ambient air to the affected section.
In addition, the experimental end stations also need to be vented regularly for setting up new experiments and therefore separated by gate valves as well. These valves have a small footprint, reliable long-term performance, and have an optimized particle performance.
In general, sector valves in synchrotron storage rings are among the more complex components within the vacuum system because the electron beam passes through them. Each valve is an interruption of the high-frequency guidance, which keeps the electrons in the synchrotron ring running. If these interruptions are not compensated, this leads to attenuation or intensity loss of the synchrotron radiation and reduces the lifetime of the beam.
“This is our core business, and we are probably the only company in the world who can design and manufacture RF all-metal sector valves that can bridge the RF-guidance with the required accuracy,” explains Takaki Kobayashi, Senior Sales Manager at VAT. The series 47 XHV RF all-metal gate valve is VAT’s workhorse for the segmentation of almost every synchrotron storage ring in the world. The valves can hermetically seal the vacuum. Their reproducible closure is tested to more than 10.000 open/close cycles. Achieving this with only metallic components is a challenge, but it is required to ensure durability within the harsh irradiation environments up to 108 Gray encountered in synchrotrons as well as to support low vacuum pressures in the storage ring. “Yet, the main difficulty is the design of the RF bridge aperture requiring individual adaption to each synchrotron”. The RF bridge maintains radiofrequency guidance as well as electrical contact through the valve. It ensures that the valves match the RF properties of the ring, thus keeping the electrons in orbit and on speed.
For this reason, the engineers of the 3GeV facility contacted VAT already in the very early planning phase to ask for customized sector valves. After discussing the details directly with the engineers in Switzerland, requirements were specified, and VAT delivered a prototype for tests, the valve performance has been excellent. However, there is more VAT technology installed in the 3GeV facility: “Our fast-closing shutters protect the main vacuum system of the ring against malfunctioning experimental end stations breaking the vacuum. This is a very important function in synchrotrons operated as multi-user environment”, elaborates Takaki Kobayashi. In less than ten milliseconds, the shutter separates the leaking experimental station from the vacuum system of the storage ring, giving the front-end valve time to hermetically seal the station.
A circle evolving to a path toward sustainability
The 3GeV synchrotron ring is now in its final phase of construction. In the end, it will contain more than 800 valves and components from VAT. The launch is anticipated for 2023, and many Japanese private-public partnerships are already preparing for the first experiments. “It is great to be part of such a complex project and to foster our country’s ambitions for technology-driven sustainability. VAT’s technical know-how in synchrotron design is very much appreciated in Japan,” knows Takaki Kobayashi. But much more, VAT acknowledges Japan’s pioneering role in technological solutions for a sustainable future. Keep going!