One of the youngest accelerators at DESY has impressively demonstrated its function: Yesterday in the early evening hours, the ARES operating team was able to operate the facility at its design energy of 155 mega-electronvolts (MeV) for the first time. The linear accelerator ARES (Accelerator Research Experiment at SINBAD) is an essential component of the new, long-term accelerator research facility SINBAD (Short Innovative Bunches and Accelerators at DESY) in the heart of DESY´s Hamburg campus in the former DORIS ring. The accelerator test facility is intended to enable accelerator research with ultra-short electron pulses, the development of new acceleration methods and beam manipulation using dielectric structures, among other things.

ARES, as a conventional S-band electron linac, will produce and accelerate ultra-short electron bunches to up to 155 MeV. Their arrival time at the end of the accelerator remains almost constant - it varies less than 10 femtoseconds for the individual particle bunches. While the design is optimized for low-charge (picocoulomb, pC) ultra-short (sub-/single femtosecond) bunches, bunch charges with several tens of pC can also be accelerated at the cost of longer bunch duration.

End of 2019 a team of young DESY scientists detected the first electrons from the ARES photoinjector. These electron bunches were characterized before they were sent to the next accelerating structure – a linear accelerator consisting of 2 travelling wave structures that accelerate the bunches up to their design energy. This goal was reached on 28th October 2020 with 155 MeV and a charge of 1.5 pC. “This success was made possible by six years of hard work by DESY scientists, doctoral students and the support from the technical groups in the M division,” says machine coordinator Florian Burkart. The ARES linac is now hardware commissioned and the period of beam characterization, optimization and preparation for the first experiments (accelerator on a chip program) will start.

“It is exciting that after the dismounting of the DORIS storage ring, now fast electrons are back in the accelerator tunnel,” says DESY leading scientist and responsible group leader Ralph Aßmann.

In 2021 the ARES linac will be further upgraded with a magnetic bunch compressor and the PolariX XBand transverse deflecting structure, a beam instrumentation device, to produce and characterize the ultra-short pulses.

“Developing new capabilities and tools for enabling forefront research is part of DESY’s DNA,” emphasizes Wim Leemans, the Director of DESY’s Accelerator Division, and adds: “It is exciting to see ARES starting to work!”