Around 50 experts from around the world met at CERN from 26 to 29 March for the second ALEGRO workshop to discuss advanced linear-collider concepts at the energy frontier.
ALEGRO, the Advanced Linear Collider Study Group, was formed as an outcome of an ICFA workshop on advanced accelerators held at CERN in 2017 (CERN Courier December 2017 p31). Its purpose is to unite the accelerator community behind a > 10 TeV electron–positron collider based on advanced and novel accelerators (ANAs), which use wakefields driven by intense laser pulses or relativistic particle bunches in plasma, dielectric or metallic structures to reach gradients as high as 1 GeV/m. The proposed Advanced Linear International Collider – ALIC for short – would be shorter than linear colliders based on more conventional acceleration technologies such as CLIC and ILC, and would reach higher energies.
The main research topics ALEGRO identified are the preservation of beam quality, the development of stable and efficient drivers (in particular laser systems), wall-plug-to-beam-power efficiency, operation at high-repetition rates, tolerance studies, the staging of two structures and the development of suitable numerical tools to allow for the simulation of the accelerator as a whole.
The next ALEGRO workshop will be held in March 2020 in Germany.