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“Beam on”: Accelerator operation restarts, experimental time is being prepared


It’s a significant moment for the scientific work at GSI Helmholtzzentrum für Schwerionenforschung and the future accelerator center FAIR. Following a two-year break during which it underwent extensive modernization, the existing accelerator facility has been restarted very successfully and will soon be supplying researchers from around the world with a large variety of high-quality ion beams. This will mark the beginning of the experiment period scheduled for 2018, which also coincides with the start of the first stage of the FAIR experimental program, or “FAIR Phase 0.”

The modernized facility is to run at a significantly higher level of performance for the future FAIR operation and will already offer unique opportunities for the "FAIR Phase 0" experimental program that is now starting. In addition to the GSI accelerators UNILAC (linear accelerator), SIS18 (ring accelerator) and ESR (experimental storage ring) as well as the existing experimental structures and the Petawatt High-Energy Laser PHELIX, FAIR components can already be used also, such as the storage ring CRYRING and a number of detectors, measuring instruments and other pieces of high-tech equipment developed especially for FAIR.

“Back in operation,” the machine is running again, was the decisive statement of the accelerator experts: That thrilling and extremely successful moment, the restart of the system, was preceded by the longest shutdown phase in the history of GSI. Over the past two years, GSI circular accelerator facilities had already been significantly improved for their future role as a pre-accelerator for FAIR. The pre-injector will be further upgraded in the future for the FAIR operation.

It was a precision landing: The process schedules drawn up two and a half years ago for shutting down and recommissioning the machines could be kept exactly to the day. The key objectives for the various parts of the existing facility have been achieved. Among other things, these include machine upgrades, the new FAIR control systems and new measurement technology. The connection, scheduled for later on, of the GSI accelerator to FAIR was also prepared. In addition, the new transformer station at the north side of the FAIR complex is already in operation for the start of the experiment period and is ensuring a more powerful electricity supply.

The scientific program now starting is a major step toward the future research at FAIR. “FAIR Phase 0” offers outstanding opportunities for experimentation. The demand from the international scientific community for the use of beam time is correspondingly high, and it underscores how attractive the FAIR project already is. Last year, an overwhelming number of scientists (over 1,000) submitted applications for beam time for the start of the FAIR research program, asking for more than twice of the currently available beam time. This shows the importance of the experimental program and the enthusiasm that prevails in the global research communities with regard to FAIR.

The period of experiments was preceded by an established selection process. The proposals were examined by an international committee, and selections were made based on scientific relevance and feasibility. 118 experiments have been granted for this and next year. Therefore, the accelerator facility will run for about 110 days per year.

During the beam times, scientists from around the world travel to Darmstadt to carry out their investigations at the facility and use the beam for experiments in a variety of fields of research, including particle physics, nuclear physics, plasma physics, biophysics and materials research.

In the coming weeks, the accelerator experts will initially be working diligently on the commissioning with beam. After testing all basic functions with beam on the machines, the machine settings required for experimental operation are tested, scientific measuring instruments are fine-tuned and the beam quality is checked. After that, finally, it’s “beam on” for science and the FAIR research program. (BP)

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The control center
The modernized facility will offer unique opportunities for research, in the picture the SIS18 ring accelerator.
The components of the system are controlled in the main control room.
Photo: J. Hosan/GSI
Photo: G. Otto/GSI