EMMA

The first non-scaling fixed field alternating gradient (NS-FFAG) accelerator in the world (EMMA), located at STFC Daresbury Laboratory, achieved first acceleration on Thursday, 31st of March. The injected beam energy has been increased by 5 MeV.

The Libera LLRF system plays a fundamental role in delivering RF power to the nineteen accelerating cavities on EMMA from a single RF amplifier source. Having gained operational experience with the new control system, the Daresbury RF team have been able to rapidly hand it over to the EMMA physics team (within only a few shifts). Through the detailed monitoring functionality of the Libera LLRF, they have been able to optimally configure the RF system to control the cavity amplitude and phase to extremely tight stability tolerances. An unexpected benefit has been the sensitivity of the Libera LLRF to show small beam-loading effects that indicate to the operators when the cavities are in accelerating mode.

The latest physics shifts during April 2011 have seen a beam injected at 12.5MeV, subsequently accelerated and then extracted from the EMMA machine at 20MeV, with a +1 MHz frequency offset between EMMA and its injector, ALICE.

“Libera LLRF has proved to be an essential tool to setup and characterize the EMMA machine,” said Andrew Moss, Senior RF engineer at ASTeC.

The EMMA machine is a proof of concept accelerator that is paving the way toward new accelerator technology that can be used for various applications from treating cancer to powering safer nuclear reactors. The next steps will be to continue the detailed characterization of the EMMA accelerator with a variable frequency offset in order to completely demonstrate the unique capabilities of this machine.

We would like to congratulate the team for the very significant achievement!