Section of the Accelerator that goes between RFQ and DTL

ESS Bilbao is responsible for the design and fabrication of the ESS MEBT as an In-Kind contribution. In the Medium Energy Beam Transport (MEBT) section the transverse and longitudinal beam characteristics are diagnosed and optimised for further acceleration in the Drift Tube Linac (DTL).

courtesy of ESS

The MEBT operates with a proton beam of 3.6 MeV and currents of 62.5 mA and nominal pulses of 2.8 ms. The MEBT is 3.81 m length for the integration of the different components. The MEBT components are installed on their dedicated vacuum vessels, which are placed over the support rafts.

A set of 11 quadrupoles is used to match the transversal beam characteristics and three RF buncher cavities to fulfil the longitudinal parameters. The beam pulse is shaped using a stripline fast chopper with rise times of less than 10 ns. The beam characterization is done with a complete set of diagnostics: wire scanner , Emittance Meter Unit, Faraday Cup, BPMs, BCMs…).



To match the RFQ output beam characteristics to the DTL input both transversally using quadrupoles, longitudinally RF buncher cavities and pulse shaping with the Fast Chopper.


Beam characterization (beam current, pulse shape, size, emittance) using a comprehensive set of diagnostics.


Control development and integration in the ESS EPICS environment.


ESS Bilbao will deliver the complete MEBT for ESS in Lund
  • Quadrupole Magnets and their correspondent power supplies.
  • Radio-Frequency Buncher cavities.
  • Low Level Radio-Frequency system (LLRF).
  • High power RF amplifiers, and corresponding distribution for MEBT.
  • Fast Chopper and beam dump.
  • Beam Instrumentation.
  • Vacuum system.
  • Interlocks system.
  • Mechanical Support, rafts, pipe and vessels.


Simulation and Modelling

The MEBT components involve multiple fields of physics and engineering. Electromagnetic analysis by means of Comsol Multiphysics, thermomechanical with Ansys, mechanical design and integration with CATIA, particle tracing with GPT or Beam Dynamics using TraceWin.

Simulation Modeling

Beam dynamics


Experimental Characterization

For the characterization and acceptance of the MEBT components different mechanics, vacuum, motion and electric and electronics tests are performed. For the characterisation of electromagnetic performance (BPMs, Buncher, Fast Chopper) specific tests are developed using ESS-Bilbao equipment.




Electronics and Control Design & Development

The electronics of the MEBT, in particular related to data acquisition and amplification, are designed and developed by ESS-Bilbao. Altium Designer provides the capability to make simulations, schematics, PCB layouts and 3D Modelling for the electronic components required for the MEBT.

The control of the MEBT is integrated in the ESS EPICS Environment and engineering GUIs using CSS are developed.


Altium 3D modeling

Control GUI