ZHAW Participates in World's Strongest Neutron Source in Sweden

The European Spallation Source is utilized for examining material properties and processes at the atomic level in fields such as medicine, renewable energy, or quantum computing. Researchers from ZHAW developed protective systems for this globally unique neutron source in Sweden.

In Lund, Sweden, the European Spallation Source (ESS) is being constructed, which will house the world's most powerful neutron source. The ZHAW School of Engineering played a significant role in developing the machine protection and personnel safety systems for this facility. By 2025, the large-scale research facility is slated to generate spallation neutrons for the first time. Researchers anticipate that the very intense and pulsed neutron beam will enable more efficient exploration of material properties. Applications span from optimizing hard drives to investigating structures in quantum computing and advancing solar cell technology, as well as elucidating molecular structures. "Neutron physics is highly intriguing for studying material structures. Neutrons penetrate denser materials better than, for example, X-rays. This enables the examination of the internal structures of objects," explains ZHAW researcher Christian Hilbes.

Proton Beam Must Halt Within Shortest Time Possible

The 600-meter-long proton accelerator, along with the adjoining rotating neutron source, was specifically developed for the European Spallation Source. Many of the accelerator's components are meticulously crafted bespoke items. Any significant changes in the proton beam could accelerate component aging or even result in damage. "Potential damages could lead to a prolonged shutdown of the facility, which should be avoided at all costs," explains Christian Hilbes. The machine protection system is designed to respond before any damage occurs. To achieve this, the system monitors numerous parameters measured along the entire length of the accelerator. If these parameters exceed predefined tolerances, a beam shutdown is swiftly executed. "Our task at the European Spallation Source was to develop concepts for the machine protection system and to implement specific subsystems. Additionally, we provided support in developing various personnel safety systems," says Hilbes.

Machine Protection System Enables Swift Shutdown

The accelerator must react extremely quickly to certain events. "The challenge was that there was no commercially available machine protection system for this purpose; instead, we had to develop it from scratch," says Christian Hilbes. Therefore, the ZHAW team developed the so-called Fast Beam Interlock System (FBIS) consisting of nearly 600 hardware units along with corresponding software. "The Fast Beam Interlock System must react within a few tens to hundreds of microseconds and operate 24 hours a day, ideally without causing false shutdowns," explains Martin Rejzek from the ZHAW School of Engineering. "The developed system comes into play, for example, when a beam current monitor detects unexpected beam intensity. It then has to decide whether to shut down the beam or not." Since the beam current monitors were developed with a focus on beam optimization rather than machine protection, several hundred signals from various systems, some of which are very different, had to be integrated into the Fast Beam Interlock System.

Involvement in Personnel Protection System

The ZHAW team was significantly involved in the design, implementation, and verification of various personnel protection systems for the European Spallation Source. "Given that it concerns personnel protection, primarily protection against radiation, very strict requirements must be adhered to in this area," explains ZHAW researcher Joanna Weng. This includes regulations regarding when a person may be present in a specific area.

European Spallation Source (ESS)

In 2014, construction commenced on the European Spallation Source (ESS) in Lund, Sweden. This research facility is a European Research Infrastructure Consortium (ERIC), comprising Sweden, Switzerland, and eleven other European countries. Alongside ZHAW, the Paul Scherrer Institute (PSI) from Switzerland also plays a significant role in the development of the ESS. The facility is currently undergoing commissioning. By 2025, it is expected to generate spallation neutrons for the first time. Scientists from various research fields anticipate more efficient exploration of material properties due to the highly intense and pulsed neutron beam.

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