The Front End Test Stand (FETS) is a high energy pulsed proton driver, a system which delivers high energy pulses of protons with potential use in next generation neutron spallation sources, neutrino factories, nuclear waste transmutation, muon accelerators and Accelerator Driven Subcritical Reactors (ADSRs).
The FETS is under construction at the Rutherford Appleton Laboratory (RAL) and involves institutions in the UK and Universidad del Pais Vasco and ESS-Bilbao in Spain. The FETS is the UKs contribution to research into next generation High Power Proton Accelerators (HPPAs) of which beam chopping will be an important feature. Beam chopping as the name suggests is ‘chopping’ the beam so that pulses or packets of particles leave the accelerator to be fed into a circular accelerator. The particles will need to be chopped at a frequency equal to the revolution frequency of the particles already in the accelerator which is one of the major challenges of the project to avoid beam loss.
The FETS will consist of an ion source which will ionize Hydrogen atoms ready for acceleration, a magnetic low energy beam transport (LEBT) which will focus the beam of ions, a Radio Frequency Quadrupole accelerator (RFQ) which will create bunches of particles and accelerate them, a medium energy beam transport and chopper line (MEBT) which will increase the separation of the bunches ready for injection into a larger circular accelerator.
Also required as part of the project are comprehensive diagnostics for the outgoing beam so that it is well understood what the beam looks like on exit, an understanding essential for potential applications requiring injection into a circular accelerator.